Exercise standards for testing and training: a scientific statement from the American Heart Association

Low chronotropic response in post-myocardial infarction exercise test predicts worse prognosis in patients with preserved or mildly reduced left ventricular ejection fraction

BACKGROUND

Chronotropic incompetence is prevalent in post-myocardial infarction (MI) patients and linked to reduced exercise capacity. However, its prognostic significance and the determination of threshold values for prognosis remain unclear.

METHODS

Ninety-six post-MI patients with left ventricular ejection fraction (LVEF) ≥ 40 % at four weeks post-event were assessed. All underwent combined exercise stress echocardiography and cardiopulmonary exercise testing (CPET-SE). The chronotropic response was expressed as a percentage of the maximal predicted heart rate (%MPHR) at peak exercise. The primary endpoint was a composite of all-cause mortality or unplanned hospitalization for coronary syndromes or heart failure.

RESULTS

Eighty-six patients completed follow-up (median: 4.0 years [IQR 2.0, 5.6]). The median age was 60 years (IQR 53, 65); 67 % were male, 86 % on beta-blockers. The median LVEF was 57 % (IQR 51, 62), and the median peak VO2 was 19 mL/kg/min (IQR 15, 22). Fifteen composite endpoint events, including three deaths, occurred. Multivariate Cox regression showed that %MPHR (HR 0.95, 95 % CI 0.92-0.98) and smoking history (HR 2.8, 95 % CI 1.1-7.4) were associated with the primary endpoint. A %MPHR threshold of 67 % best predicted the primary endpoint (AUC 73 %, PPV 29 %, NPV 95 %, sensitivity 87 %, specificity 55 %). Patients with %MPHR <67 % had significantly more composite endpoint events than those with %MPHR ≥67 % (p = 0.002).

CONCLUSIONS

A chronotropic response below 67 % of the maximal predicted heart rate is a negative prognostic marker in post-MI patients with preserved or mildly reduced LVEF. This threshold may help risk-stratify and guide management in this population.

Unveiling the limitations of non-metabolic thresholds in assessing maximal effort: The role of cardiopulmonary exercise testing

INTRODUCTION

Maximal effort, defined by a respiratory exchange ratio (RER) ≥ 1.10, is crucial for accurate interpretation of cardiopulmonary exercise testing (CPET). Standard tests rely on non-metabolic thresholds, such as peak predicted heart rate (ppHR) ≥ 85 %, double product (DP) ≥ 20,000 bpm*mmHg and peak metabolic equivalent of task (MET) ≥ 5.0. This study aimed to assess the effectiveness of non-metabolic thresholds in detecting maximal effort, compared with the RER ≥ 1.10 criterion.

METHODS

We retrospectively analyzed stable patients who underwent CPET from 2022 to 2023, regardless of test indication, history of heart failure (HF), or medication use. All patients also performed transthoracic echocardiography.

RESULTS

Among 239 middle-aged patients (53 ± 14 years, 67 % male), 86 % achieved a RER ≥ 1.10, and 65 % had a diagnosis of HF. Non-metabolic thresholds correctly identified maximal efforts (RER ≥ 1.10) in 75 % of the cases (AUC < 0.600). Misclassified cases were more likely to have a history of atrial fibrillation (AF), paced rhythm, HF, and beta-blockers or RAAS inhibitors use. These patients exhibited lower VO2 peak and higher VE/VCO2 slope. Multivariable analysis identified HF history (OR 4.8, CI 95 % 1.6-15.6, p: 0.005), low resting DP (≤ 7500 mmHg*bpm), and ramp protocol as independent predictors of discordant tests.

CONCLUSION

Non-metabolic thresholds misclassified up to 25 % of tests with RER ≥ 1.10 as non-maximal, potentially leading to inaccurate interpretation. In patients with HF, poor expected functional capacity and low DP, direct referral to CPET-equipped facilities may provide more accurate assessment than relying on non-metabolic thresholds.

Correlation between workload-indexed blood pressure response to exercise (SBP/MET slope) and clinical and echocardiographic parameters among normotensive Olympic athletes

INTRODUCTION

The workload-indexed systolic blood pressure response to exercise (SBP/MET slope) has been proposed as a novel parameter for evaluating abnormal blood pressure response to exercise (ABPR) and its potential risks. Aim of our study was to assess the association between SBP/MET slope and clinical and cardiac dimensional parameters in normotensive athletes.

METHODS

A cohort of 292 normotensive Olympic athletes (155 male, 53.1 %) underwent a pre-participation evaluation that included clinical, echocardiographic, and exercise-stress test parameters. The SBP/MET slope was calculated as the increase in systolic blood pressure indexed to metabolic equivalents achieved during maximal exercise. Athletes were stratified into quartiles based on their SBP/MET slope, and comparisons across quartiles were made.

RESULTS

Athletes in the highest SBP/MET slope quartile exhibited increased left ventricular wall thickness, i.e., interventricular septum (IVS) compared to those in lower quartiles (10.3 ± 0.9 vs. 9.5 ± 1.1, p = 0.014). Male athletes predominated in higher quartiles (p = 0.047), and endurance athletes were absent in the higher groups (p = 0.006). No differences were observed for systolic or diastolic function across quartiles. At multivariate analysis, SBP/MET slope was indipendently correlated to IVS (p = 0.040; R2 = 0.566, standardized beta coefficient = 0.368) and inversely correlated to W/Kg (p = 0.014; R2 = 0.566, standardized beta coefficient = -0.507). After a follow-up of 10.3 ± 2.6 years, 13.6 % of athletes in the highest quartile developed hypertension.

CONCLUSION

Athletes with higher SBP/MET slope exhibited increased wall thickness and lower exercise capacity and showed higher risk for late-onset hypertension. Long-term follow-up studies are warranted to further elucidate its prognostic implications.

Effects of Different Eccentric Cycling Intensities on Brachial Artery Endothelial Shear Stress and Blood Flow Patterns

Eccentric exercise has gained attention as a novel exercise modality that increases muscle performance at a lower metabolic demand. However, vascular responses to eccentric cycling (ECC) are unknown, thus gaining knowledge regarding endothelial shear stress (ESS) during ECC may be crucial for its application in patients. The purpose of this study was to explore ECC-induced blood flow patterns and ESS across three different intensities in ECC. Eighteen young, apparently healthy subjects were recruited for two laboratory visits. Maximum oxygen consumption, power output, and blood lactate (BLa) threshold were measured to determine workload intensities. Blood flow patterns in the brachial artery were measured via ultrasound imaging and Doppler on an eccentric ergometer during a 5 min workload steady exercise test at low (BLa of 0-2 mmol/L), moderate (BLa 2-4 mmol/L), and high intensity (BLa levels > 4 mmol/L). There was a significant increase in the antegrade ESS in an intensity-dependent manner (baseline: 44.2 ± 8.97; low: 55.6 ± 15.2; moderate: 56.0 ± 10.5; high: 70.7 ± 14.9, all dynes/cm2, all p values < 0.0002) with the exception between low and moderate and Re (AU) showed turbulent flow at all intensities. Regarding retrograde flow, ESS also increased in an intensity-dependent manner (baseline 9.72 ± 4.38; low: 12.5 ± 3.93; moderate: 15.8 ± 5.45; high: 15.7 ± 6.55, all dynes/cm2, all p values < 0.015) with the exception between high and moderate and Re (AU) showed laminar flow in all intensities. ECC produced exercise-induced blood flow patterns that are intensity-dependent. This suggests that ECC could be beneficial as a modulator of endothelial homeostasis.

Cardiopulmonary responses to acute exogenous ketosis at rest, and during submaximal and maximal exercise

Nutritional ketosis achieved through various methods in animals and humans has been shown to augment cardiac efficiency and function. However, this response during exercise has not been well characterized. Recreationally active adults (n = 12) completed a double blind, balanced, placebo-controlled, crossover study to examine the effects of bis-octanonyl (R)-1,3-butanediol (BO-BD) ingestion on cardiopulmonary function at rest and during a maximal oxygen consumption (V̇O2max) treadmill test (Bruce Protocol). Participants presented to the testing facility fasted. Capillary blood samples were obtained to measure glucose and beta-hydroxybutyrate (R-βHB) prior to consuming the BO-BD or a calorically matched placebo (PL) beverage. Metabolic and cardiovascular measures were collected every 15-30 min following beverage consumption. Participants began the V̇O2max test 120 min post-beverage ingestion. At rest, capillary R-βHB elevated rapidly after BO-BD ingestion and continued to steadily increase to 2.4 mM prior to the maximal exercise test. During the 120 min rest period, BO-BD increased resting heart rate (HR) (p = 0.001), ventilation (p < 0.001), and V̇O2 (p = 0.002) relative to PL. Although the total time to exhaustion was similar between conditions, V̇O2max was lower after BO-BD (p < 0.001). There were no differences in exercise lactate, RER, respiration, or rating of perceived exertion (RPE) between conditions. Compared to PL, BO-BD rapidly achieves nutritional ketosis, increases resting cardio-respiratory parameters, but somewhat paradoxically decreases peak aerobic exercise oxygen consumption despite achieving similar peak workloads.

Safety and feasibility of exhaustive exercise testing for people with epilepsy

People with epilepsy (PWE) are encouraged to participate in exercise and be physically active, but some PWE may report exercise-associated seizures (EAS). However, there is a lack of objective tools to inform individual recommendations for physical activity and exercise participation in PWE. This study investigated the feasibility and safety of exhaustive exercise testing in PWE. 29 patients underwent an objectively and subjectively exhaustive exercise test on a bicycle ergometer and resting state EEG was obtained before and after exercise. One patient with a history of EAS experienced a seizure immediately after exercising. In patients without EAS, an asymptomatic subclinical electrographic seizure was observed in one patient, and two patients revealed interictal epileptiform discharges only after exercise. All EEG changes occurred in the setting of non-REM sleep, while the respective pre-exercise EEG recordings revealed less sleep. No seizures or significant EEG changes after exercise were observed in any other patient. EEG investigations before and after exhaustive exercise were feasible in PWE, but safety protocols need to be established, especially in patients with EAS. Investigation of a higher number of PWE with and without EAS with repeat exercise-associated EEG may provide information about the clinical utility of exercise-associated EEGs when counseling PWE.

Influence of sex and aerobic fitness on blood pressure during maximal treadmill exercise in young healthy adults

Exaggerated exercise blood pressure (BP) is a predictor of future hypertension but commonly observed in athletes despite their reduced cardiovascular risk. Normalizing exercise BP to metabolic or mechanical work may provide better discrimination between physiological and pathological responses. This study investigated the effects of sex and aerobic fitness on peak systolic BP (SBP) and peak SBP per metabolic equivalent (SBP/MET slope). One hundred and eleven healthy adults (22 ± 5 years; 51 female) performed a graded maximal treadmill exercise test (modified Bruce protocol) with brachial BP measured using automated auscultation (Tango M2, SunTech Medical). Peak oxygen uptake rate (V̇o2peak) was assessed using indirect calorimetry. Males had a higher relative V̇o2peak (P < 0.01) but not V̇o2peak percentile (P = 0.16). Peak SBP was higher in males (208 ± 26 vs. 182 ± 23 mmHg, P < 0.01), while the SBP/MET slope did not differ between sexes (6.5 ± 2.4 vs. 6.3 ± 2.6 mmHg/MET, P = 0.60). Adjustment for differences in body mass index and V̇o2peak did not alter these results. The SBP-V̇o2peak regression slope did not differ between sexes (P = 0.92), with both slopes not different from zero (both, P > 0.47). The SBP/MET-V̇o2peak regression slope did not differ between sexes (P = 0.43), but both slopes were different from zero (both, P < 0.001). The present cohort demonstrated sex differences in peak SBP but not the SBP/MET slope. The SBP/MET slope was lower in individuals with higher aerobic fitness, but the influence of V̇o2peak did not differ between sexes. Using the SBP/MET slope in cross-sectional studies can reduce the confounding effects of sex on peak SBP, but differences in participant aerobic fitness should be considered.NEW & NOTEWORTHY Higher peak systolic blood pressure (SBP) during exercise is linked with an increased risk of developing hypertension. It has been suggested that exercise SBP should be normalized to mechanical or metabolic work to account for differences in aerobic fitness. We found that the influence of aerobic fitness on peak SBP or SBP per metabolic equivalent (SBP/MET slope) does not differ between sexes but that the SBP/MET slope is lower in participants with higher aerobic fitness.

Exercise capacity after long-term physical activity on prescription provided by physiotherapists

Background: Research has shown that physical activity on prescription (PAP), used in Swedish healthcare, increases patients' physical activity, but data are lacking regarding the long-term effects of PAP on exercise capacity. Therefor exercise capacity was evaluated in patients with metabolic risk factors, after 4.5 years of PAP treatment provided by physiotherapists in primary healthcare.

Method: This study included 98 patients (49% women; mean age, 56 years) with metabolic risk factors, who were still physically inactive after a previous 6-month PAP treatment. The patients received physiotherapist-provided PAP treatment for 4.5 years, including 11 follow-ups and 6 exercise capacity tests.

Results: After 4.5 years, 41 patients completed the final exercise capacity test (58% drop-out rate). Compared to baseline, the whole cohort exhibited a significantly increased exercise capacity (9.1 W, p = 0.014) with a small effect size (r = 0.27), with no significant differences associated with age or gender.

Conclusion: The increased exercise capacity may indicate positive effects on longevity, and consolidates previous findings that long-term behavior change is possible among physically inactive patients. It also demonstrates the feasibility of continuous exercise capacity testing with physiotherapist support in an ordinary primary care setting. The drop-out rate and lack of control group complicate the interpretation of the effects of PAP treatment on the increased exercise capacity. Further research should strive for an RCT study design.

Breaking up prolonged sedentary behavior to improve cardiometabolic health (BREAK2): protocol for a dose-finding adaptive randomization trial

BACKGROUND

Excessive sedentary behavior is highly prevalent in developed nations and is a risk factor for cardiovascular disease (CVD) morbidity and mortality. As such, health agencies have provided general recommendations to "sit less, move more" by interspersing brief periods of activity. However, a lack of empirical evidence describing how often (e.g. every 30 min, every 60 min) and for how long (e.g., 1 min activity bouts, 5 min activity bouts) sedentary time should be interrupted (a "sedentary break") to yield health benefit has precluded more quantitative, actionable guidelines. To date, rigorous and methodical dose escalation experiments have not been conducted to elucidate effective and tolerated sedentary break doses. The objective of the proposed study is to determine the minimally effective dose (e.g., the lowest dose) for two elements of a sedentary break (frequency and duration) that yields improvements in established CVD risk factors. The maximally tolerated dose (e.g. the highest dose that does not cause undue physical/psychological distress) for both frequency and duration of sedentary breaks will also be determined.

METHODS

This study is a randomized crossover trial conducted under laboratory conditions among 324 adults without chronic medical conditions. Participants complete two trial conditions (8 h each), a sedentary break (intervention) condition and an uninterrupted sitting (control) condition, in a randomized order. The sedentary break condition consists of 1 of 25 possible frequency/duration combinations (e.g. walk every 30 min for 5 min), selected according to a Bayesian adaptive randomization method. Primary outcomes used to inform the adaptive randomization are glucose and blood pressure serially assessed over each trial condition. Constructs of dose toxicity (tolerability, safety, physical exhaustion/fatigue, and affect) are also serially assessed.

DISCUSSION

This study will elucidate the minimally effective and maximally tolerated frequency and duration of a sedentary break that yields improvements in established CVD risk factors, information important for the development of quantitative sedentary behavior guidelines.

TRIAL REGISTRATION

This trial has been registered with the Clinical Trials Registry maintained by the National Library of Medicine at the National Institutes of Health on April 29, 2022. The registration ID is NCT05353322.

Fitness and Mortality Outcomes Associated With Supramaximal Peak Heart Rate on Treadmill Exercise Stress Testing

Inability to reach age-predicted peak heart rate (APPHR) on treadmill exercise testing (TMET) is associated with lower fitness and increased mortality. The significance of a "supramaximal" heart rate (≥105% of APPHR) is poorly understood; as such, we sought to investigate this relationship. We queried the Mayo Stress database from 1993 to 2010 for patients >30 years old without cardiovascular disease and not on antichronotropic therapy. Patients were stratified into groups based on APPHR: <75%, 75% to 84%, 85% to 94%, 95% to 104%, and ≥105%, with 105% to 114% and ≥115% subgroups. Functional aerobic capacity (FAC) was assessed by ANOVA and all-cause mortality by cox hazard regression; we adjusted for confounders. In total, 18,961 patients were included; 1150 (6.1%) died. 2,144 (11.3%) of patients achieved submaximal APPHR (<85%), 2,917 achieved supramaximal APPHR (≥105%). Patients with submaximal APPHR had significantly lower FAC: 76.4% (p <0.0001) [<75%], 83.5% (p <0.0001) [≥75% to <85%]. Those with supramaximal APPHR had significantly higher FAC: 102.0% (p <0.0001). Patients with submaximal APPHR had significantly higher mortality risks: <75% (adjusted HR 2.36 [1.83 to 3.04], p <0.0001) and ≥75 to <85% (adjusted HR 1.93 [1.62 to 2.31], p <0.0001). Those with supramaximal APPHR, after adjustment for cardiac risk factors and resting heart rate, had significantly lower mortality risk (adjusted HR 0.83 [0.70 to 0.99], p = 0.0414). In conclusion, supramaximal heart rate on TMET was associated with significantly higher FAC and lower all-cause mortality risk.

Predicting the sport level in elite male motorcycle speedway riders based on physical profile and experience

The main objective of this research was to analyze the physical profile and experience of elite male motorcycle speedway riders, in order to develop a mathematical model to predict their level of sport performance. One hundred and eleven male professional motorcycle speedway riders in the top Polish motorcycle speedway league participated in this study (age: 25.04 ± 6.03 years, height: 172.28 ± 4.76 cm, weight: 65.60 ± 4.66 kg). The riders were divided by the k-means clustering method into three groups of sport level: high (n1 = 31), medium (n2 = 30), low (n3 = 50). To define sport level, several parameters were normalized and aggregated into a new conceptual metric of sport level called 'Indicator of Sport Level' (ISL). Body composition assessment, Wingate Anaerobic Test on a cycloergometer, and analysis of acute cardiorespiratory and biochemical responses were performed. One-way ANOVA tests were performed for independent samples, and Pearson's r linear correlation was calculated between clusters of riders. Multiple linear regression (MLR) was performed to predict the ISL. The elite male motorcycle speedway athletes were characterized by average age (25.10 ± 5.80 years) and years of experience (9.16 ± 5.62 years), which made them different from other clusters (p < 0.05). Also, they were 1.99% taller (173.02 ± 4.91 cm) than low sport level riders (p = 0.003). The strongest predictive variable of sport level in the regression model (R2 = 0.28) was body height (p = 0.043) and sport experience (p < 0.001). The results of this study present the optimal range of physical attributes, body height, sports experience, age, and body surface area of the best motorcycle speedway riders and indicate that body height and experience are the most predictive parameters in the model to estimate the sport level of riders.

Multimodal Web-Based Telerehabilitation for Patients With Post-COVID-19 Condition: Protocol for a Randomized Controlled Trial

BACKGROUND

Patients with post-COVID-19 condition (PCC) experience persistent, long-term health consequences following SARS-CoV-2 infection, including fatigue, hyperventilation, cognitive impairment, and limitations in daily activities. There is emerging evidence suggesting that exercise and respiratory therapy-based telerehabilitation is safe and could potentially improve physical capacity while reducing health care costs.

OBJECTIVE

This study aims to evaluate the superiority of a multimodal, symptom-titrated telerehabilitation program over standard care in patients with PCC who are severely affected, using the highest oxygen uptake rate (VO2peak [mL/min/kg]) achieved during the cardiopulmonary exercise test (CPET) and minute ventilation/carbon dioxide production slope (VE/VCO2 [full slope]) as primary outcomes. In addition, this study seeks to provide novel insights into the clinical and physiological adaptations associated with PCC, informing future rehabilitation strategies.

METHODS

This prospective, randomized, waitlist-controlled trial was approved by the Rhineland-Palatinate Medical Association ethics committee. All procedures comply with the Declaration of Helsinki. This study comprises 3 examination time points, which include patient-reported outcomes, clinical assessments, and a CPET. It is structured into an 8-week intervention phase followed by an 8-week follow-up phase. Following baseline assessment, patients will be randomly assigned to either the intervention group (IG) or the control group (CG). During the intervention phase, IG participants will receive a web-based, multimodal, symptom-titrated telerehabilitation program consisting of sports medicine consultations, weekly teleconsultations, a structured pacing approach, and exercise and respiratory therapy. In contrast, CG participants will receive treatment as usual, which includes a single sports medicine consultation on healthy habits and a self-directed pacing approach for managing symptoms and daily activities. During the follow-up phase, IG participants will continue training independently without teleconsultations, whereas CG participants will undergo the same telerehabilitation intervention as the IG. A follow-up assessment will be conducted for both groups to evaluate long-term effects. This study adheres to the SPIRIT (Standard Protocol Items: Recommendations for Interventional Trials) guidelines and follows the Consensus on Exercise Reporting Template.

RESULTS

Recruitment began in August 2023 and was extended until March 2025. As of March 2025, 80 participants have been recruited, and data analysis is ongoing. Final results are expected by December 2025, with a cross-sectional analysis of baseline data anticipated by July 2025.

CONCLUSIONS

This study is the first randomized controlled trial investigating the effectiveness of multimodal and symptom-titrated telerehabilitation in patients with PCC who are severely affected. The integration of various objective diagnostic systems will provide valuable insights into emerging postviral fatigue syndromes, supporting the development of CPET-based diagnostics, personalized rehabilitation strategies, and future research on long-term telerehabilitation effectiveness. The findings will be disseminated through peer-reviewed publications, professional networks, and patient advocacy groups to ensure scientific, clinical, and public impact.

TRIAL REGISTRATION

German Clinical Trials Register (DRKS) DRKS00032394; https://drks.de/search/de/trial/DRKS00032394.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/65044.

The content of physical fitness training and the changes in physical fitness and functioning in orthopedic geriatric rehabilitation: an explorative observational study

PURPOSE

This explorative study investigates the content of physical fitness training and changes in physical fitness and functioning in the current practice of orthopedic geriatric rehabilitation (GR) in the Netherlands.

MATERIALS AND METHODS

The content of physical fitness training was analyzed in 48 patients from 11 orthopedic GR wards, comparing it to general guidelines for older adults. Endurance, muscle strength, and functioning were measured at admission and discharge. Correlations between training volume and change in endurance, knee-extensor muscle strength, and physical functioning were assessed.

RESULTS

Training characteristics varied substantially among individuals. Compared to guidelines, endurance time and intensity were low, and muscle strength training volume was low to moderate. Significant improvements (17.7-41.4%) in muscle strength and all measures of physical functioning were observed. Pain highly affected endurance outcomes in the majority of the patients. Patients not limited by pain showed no change in endurance. Only resistance training volume of the affected leg moderately correlated with change in muscle strength.

CONCLUSIONS

Physical fitness training content varied and was generally low in intensity compared to guidelines. Its relation to fitness and functioning was limited. Future efforts should focus on improving training strategies and developing a valid measure of endurance.

Breaking prolonged sitting with high-intensity interval training to improve cognitive and brain health in middle-aged and older adults: a protocol for the pilot feasibility HIIT2SITLess trial

INTRODUCTION

Excessive sedentary time (ST) is linked to dementia risk, poorer attentional control and episodic memory. These cognitive decrements have been associated with decreased functional connectivity (FC) in the frontoparietal network (FPN) and default mode networks (DMN) with ageing. Physical activity (PA) interventions can enhance FC in these networks, but these interventions are not designed to decrease ST among older adults. Prolonged sitting (ie, sitting continuously for ≥20 min) can acutely reduce frontoparietal brain function and attentional control, while a single PA bout lasting at least 20 min can enhance them. It has been theorised that stimulation of the cerebral norepinephrine release through peripheral increase in catecholamines may explain this effect. In contrast, the effects of shorter (<10 min) PA bouts used to interrupt prolonged sitting on neurocognitive functions remain poorly understood. This pilot randomised crossover feasibility trial capitalises on PA intensity as the major limiting factor in peripheral catecholamine increase and tests the effects of interrupting prolonged sitting every 30 min with 6 min high-intensity interval training (HIIT) compared with low-intensity interval training (LIIT) bouts. The study will address three aims: (1) to assess feasibility, acceptability, fidelity and safety of HIIT breaks to improve neurocognitive function in middle-aged and older adults; (2) to quantify the differences between conditions in the change in the amplitude and latency of the P3b component of event-related potentials (a marker for frontoparietal function) and (3) to explore the differences between conditions in attentional control, episodic memory and FC of the FPN and DMN in middle-aged and older adults.

METHODS AND ANALYSIS

54 healthy adults, aged 40-75 years, will be recruited from the local community and randomly assigned to a condition sequence (HIIT, LIIT vs LIIT and HIIT). Each HIIT bout comprises a 1 min warm-up, 2 min at 90% of the maximum heart rate (HRmax), 1 min passive rest and 2 min at 90% HRmax. During 2 min intervals in LIIT, participants exercise at 57%-60% of HRmax. The primary outcomes include the feasibility (recruitment and retention rates, percentage of valid electroencephalogram data), acceptability of time commitment, HIIT bouts and neurocognitive assessments, fidelity (the intensity of HIIT breaks, percentage of time spent sitting) and the amplitude and the latency of the P3b component of event-related brain potentials measured during the modified Eriksen flanker task at pretests, after the first and the third PA bout and at post-test. General linear mixed-effects models will be used to test the effects of the intervention on the P3b component.

ETHICS AND DISSEMINATION

The Institutional Review Board at the University of Illinois Urbana-Champaign provided the ethical approval for the study. Findings will be disseminated in peer-reviewed journals and at scientific conferences.

TRIAL REGISTRATION NUMBER

NCT06243016.

Exercise-based cardiac rehabilitation for heart failure: effects on echocardiographic parameters and functional capacity: a randomized clinical trial

Introduction

Multiple comorbidities and physiological changes play a role in a range of heart failure (HF) conditions and influence the most effective approach to exercise-based rehabilitation. This research aimed to examine and compare the outcomes of concurrent exercise training, focusing on echocardiographic parameters and functional capacity of patients with heart failure with reduced ejection fraction (HFrEF).

Methods

In this randomized control trial, a total of 76 patients (average age: 68.2 ± 4.8 years) with HFrEF were randomly allocated into two groups: intervention group (IG, N = 38) and control group (CG, N = 38) that IG performed an 8-week concurrent exercise training (three aerobic and two resistance exercise sessions/week) and daily breathing exercises. Echocardiographic parameters (left ventricular ejection fraction, left ventricular end-diastolic dimension, left ventricular end-systolic dimension, and functional capacity (6-minute walking test) were assessed before and the end of the study.

Results

The comparison of CG and IG showed that 6-min walking test (204.2 ± 28.72 vs. 273 ± 38.37) and ejection fraction (EF) (28.28 ± 4.39 vs. 37.23 ± 6.54) had increased, and left ventricle end-diastolic dimension (53.89 ± 4.73 vs. 46.71 ± 5.35) and left ventricle end-systolic dimension (45.55 ± 4.8 vs. 39 ± 5.26) had decreased after 8 weeks, respectively (P < 0/05).

Conclusion

In summary, this study provides compelling evidence that exercise-based cardiac rehabilitation can lead to meaningful improvements in echocardiographic parameters and functional capacity among older adults with HF, advocating for its broader implementation in clinical settings.

Wearable Devices for Exercise Prescription and Physical Activity Monitoring in Patients with Various Cardiovascular Conditions

As wearable technologies have become increasingly affordable, accessible, and practical, an increasing number of people with cardiovascular disease are beginning to use consumer-grade devices. Common health and wellness metrics reported by wearable devices include heart rate, heart rhythm, and step count, which may afford opportunities to assess cardiovascular conditions, prescribe more personalized exercise for enhanced engagement, and monitor physical activity adherence in patients with cardiovascular disease. This narrative review discusses the application of wearable devices in patients with coronary artery disease, heart failure, atrial fibrillation (AF), cardiac implantable electric devices, and peripheral artery disease in different cardiovascular rehabilitation settings (eg, supervised and home-based). Available literature suggests that, when combined with telemonitoring, wearable devices can increase physical activity participation, thereby improving peak oxygen consumption (V ˙ O2peak) and quality of life (QoL) in patients with coronary artery disease, enhancing physical function and QoL in patients with heart failure, and increasing walking capacity andV ˙ O2peak in patients with peripheral artery disease. Wearable devices can also detect AF vs sinus rhythm, guide exercise timing in patients with AF, and monitor safe exercise intensity in patients equipped with cardiac implantable electric devices. Healthcare professionals can promote physical activity by incorporating wearable devices, which can help motivate device users by providing real-time feedback on their behaviours. Commercially available wearable devices have the potential to enhance engagement in physical activity, thereby augmenting the established effects of exercise programs onV ˙ O2peak, functional capacity, and QoL in patients with various cardiovascular conditions.

Neuromuscular Electrical Stimulation to Maximize Hip Abductor Strength and Reduce Fall Risk in Older Veterans: Protocol for a Randomized Controlled Trial

BACKGROUND

Nearly half of all veterans are 65 years and older, and they have a higher prevalence of functional disabilities compared to the nonveteran population. Balance impairments resulting in injurious falls are a leading cause of morbidity and mortality in older adults. Instability or fear of falling can significantly reduce physical activity and social participation, even in the absence of falls. Dysmobility is a leading factor in long-care admissions, and therefore, maintenance of mobility throughout aging is crucial. Recent evidence indicates lower extremity muscle weakness as a key risk factor for falls, with lower limb muscle strength and quality being critical for balance recovery. The primary hip abductors, the gluteus maximus, medius, and minimus, are particularly essential for balance recovery.

OBJECTIVE

This study aims to test the hypothesis that adding neuromuscular electrical stimulation (NMES) to a multimodality balance intervention (MMBI) will yield greater reductions in fall risk and improvements in muscle and mobility function compared with MMBI alone.

METHODS

This randomized controlled trial will enroll 80 veterans aged 55 years and older at risk for falls (defined by a four-square step test [FSST] time >12 seconds, history of falls, or fear of falling). Participants will be randomized to receive either NMES + MMBI or MMBI alone. The 12-week outpatient center-based intervention will include 3 sessions per week, focusing on hip abductor strength, balance, and mobility. Assessments will occur at baseline, postintervention, and at 6- and 12-month follow-ups. Primary outcomes include fall risk and dynamic balance, measured by FSST and hip abductor strength using a Biodex dynamometer. Secondary outcomes will examine muscle composition through computed tomography (CT) scans and assess gait variability parameters.

RESULTS

This study was funded on January 1, 2022, with a data collection period from April 1, 2022, to December 31, 2026. As of March 2025, we have screened 100 potential participants and excluded 38. Out of the 61 participants enrolled to date, 21 have completed the 12-month follow-up, 32 have completed the 6-month follow-up, and 41 have completed the posttesting. A total of 4 participants are currently in the intervention phase; 1 has just completed the baseline testing, while 15 have been dropped from the study.

CONCLUSIONS

This trial will be the first large, randomized controlled trial to evaluate NMES as an adjunct to an MMBI for fall prevention in older veterans. If successful, NMES combined with hip abductor strengthening and balance training could provide a low-cost, scalable solution to reduce falls, improve balance and mobility, and decrease health care costs related to falls in older adults. This study will address a critical gap in knowledge about the effectiveness of NMES in enhancing rehabilitation outcomes for fall prevention.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04969094; https://clinicaltrials.gov/study/NCT04969094.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/68082.

Cardiorespiratory Fitness in Spanish Youth: The Roles of Sex, Age, Body Composition, and Healthy Lifestyle Habits in Cor-School Study

Background/Objectives: Cardiorespiratory fitness (CRF) is a key indicator of current and future health in children and adolescents, and is influenced by both physiological and behavioral factors. This study examined the associations between CRF, body composition, and health-related habits in 685 children and adolescents (aged 8-16 years) who regularly participated in extracurricular sports programs in northeastern Spain. Methods: Participants underwent anthropometric assessments, completed a 20 m shuttle run test to evaluate CRF, and filled out validated questionnaires on physical activity levels, sleep quality, and adherence to the Mediterranean diet. Results: Significant sex differences were observed, with boys achieving higher CRF performance (p < 0.001), primarily associated with greater muscle mass (p < 0.001) and lower body fat percentage (p < 0.001). Age positively correlated with improved CRF (p < 0.001), whereas higher body mass index (p = 0.003) and fat mass (p = 0.020) negatively impacted fitness outcomes. Conclusions: These findings underscore the critical role of physical activity and optimal body composition in promoting cardiorespiratory fitness among youth, emphasizing the importance of targeted interventions to foster healthy behaviors from early childhood. Future research should adopt longitudinal designs to better elucidate the dynamic interactions between lifestyle factors, body composition, and physical fitness throughout childhood and adolescence.

Altered cardiac contractility and aerobic muscular capacity markers during exercise in patients with obesity and DMT II

BACKGROUND

Impaired exercise capacity influences obesity and diabetes disease progression and vice versa. The primary objective of this prospective, observational, real-world study was to characterize exercise capacity in patients with obesity or type II diabetes mellitus and healthy controls by cardiac capacity (cardiac output (CO), cardiac power output (CPO)) and peripheral muscle capacity (peak power output (Pmax) and arterio-venous oxygen difference (avDO2)). The effects of an exercise and lifestyle intervention on these cardiac and peripheral muscular markers in obese and diabetic patient groups were additionally evaluated.

METHODS

At a university sports medicine outpatient clinic, 24 obese (OB) and 38 diabetes mellitus type II (DM) patients and 20 healthy controls (HE) were investigated in a cross-sectional analysis. OB and DM were reexamined after a standard of care exercise intervention. Parameters were assessed at rest and during a cardiopulmonary exercise test (CPET). Blood pressure, impedance cardiography, and respiratory gas analysis were continuously recorded during CPET.

RESULTS

At Pmax, CO and CPO were lower in DM compared to obese (CO 16.26 l/min vs. 18.13 l/min, p < 0.04; CPO 5.67 W vs. 4.81 W, p < 0.01). HE did not differ in CO (18.19 l/min)) or CPO (5.27 W) from OB and DM. Maximum CPO in OB and DM was based on higher stroke volume and blood pressure, while HE had higher heart rates. Pmax was higher (p < 0.01) in HE (268 W) compared to OB (108 W) and DM (89 W), mainly caused by a higher (p < 0.01) avDO2 (HE 18.22 ml/dl, OB 10.45 ml/dl, DM 9.65 ml/dl). Exercise intervention improved Pmax in both groups of patients (+ 16 W in OB, + 12 W in DM), which was attributed to increased avDO2, but not to cardiac parameters.

CONCLUSIONS

Obese patients had higher cardiac power outputs and were primarily limited by muscular performance, while diabetic patients showed both muscular and cardiac limitations. Healthy subjects had comparable cardiac power outputs with significantly lower pressure-volume loads. Resistance training improved the alteration of our patient groups in exercise capacity. Future research is needed to interpret our findings regarding clinical endpoints, such as mortality and hospitalization.

TRIAL REGISTRATION

The study was retrograde registered in the German Clinical Trial Register (DRKS00032545, 24.08.2023).

Comparison of inspiratory muscle strength and aerobic exercise training and detraining on blood pressure in hypertensive patients

Background

This study evaluated the effectiveness of inspiratory muscle strength training (IMST) as a time-efficient alternative to widely recommended aerobic exercise (AE) for reducing and maintaining blood pressure in hypertensive patients.

Methods

Twenty-eight hypertensive patients (aged 61 ± 7 years) were randomly assigned to IMST (n = 14) and AE (n = 14) groups. The IMST performed 30 breaths/session at 75% of maximal inspiratory pressure (PImax), totaling about 8 minutes, 5 days/week. The AE group exercised at 70% of heart rate reserve for 30 minutes/session, 5 days/week. Both supervised interventions lasted 8 weeks, followed by a 4-week detraining period. Brachial and central systolic blood pressure (SBP) were taken at baseline, 8-week post-intervention, and post-detraining.

Results

The mean (standard deviation) change in brachial SBP from baseline to 8 week post-intervention significantly decreased in both the IMST group [-9.1 (12.1) mmHg, P = 0.01] and the AE group [-6.2 (7.2) mmHg, P = 0.01], with no significant difference between groups (P = 0.46). Central SBP also significantly reduced in the IMST group [-9.0 (11.9) mmHg, P = 0.01] and in the AE group [-5.7 (6.2) mmHg, P = 0.01], with no significant difference between groups (P = 0.37). However, the IMST group did not show significant persistence in SBP reduction, whereas the AE group did.

Conclusions

Both IMST and AE effectively reduced brachial and central BP after 8-week interventions in hypertensive patients. While IMST presents a time-efficient adjunctive option to AE, its long-term effectiveness remains uncertain.

Advanced Liver Fibrosis Impairs Cardiorespiratory Fitness in Patients with Metabolic Dysfunction-Associated Steatotic Liver Disease

BACKGROUND

MASLD is a leading reason for liver transplant waitlisting. The relationship between cardiorespiratory fitness (CRF) and liver fibrosis in patients with MASLD remains unclear. This study aims to provide further evidence supporting the relationship between liver fibrosis and CRF.

METHODS

Participants with MASLD across various fibrosis stages, including those with cirrhosis awaiting liver transplantation from three U.S. transplant centers, underwent cardiopulmonary exercise testing (CPX). We compared participants based on fibrosis stage (F0-F1, F2-F3, and F4) and CPX parameters such as VO2peak, respiratory exchange ratio (RER), ventilatory efficiency (VE/VCO2), double product (DP) and chronotropic incompetence (CI). Multivariable models were then built to evaluate factors associated with these parameters.

RESULTS

Sixty-one participants underwent CPX testing across three centers. Participants with F4 had lower VO2peak (11.8 mL/kg/min) compared to F0-F1 (22.2 mL/kg/min) and F2-F3 (22.9 mL/kg/min), p < 0.001. Participants with F4 had higher RER (median 1.25) compared to F0-F1 (1.08) and F2-F3 (1.05), p = 0.001. Similarly, F4 participants exhibited higher VE/VCO2 (median 36.5) compared to F0-F1 (31) and F2-F3 (30), p < 0.001. Additionally, F4 participants had lower DP values (median 17,696) compared to F0-F1 (25,460) and F2-F3 (25,372), and higher prevalence of CI (90%) compared to F0-F1 (39%) and F2-F3 (25%), both p =  < 0.001. Multivariable modeling confirmed advanced fibrosis (F > 3) as an independent predictor of low CRF.

CONCLUSIONS

In MASLD patients, advanced liver fibrosis, particularly cirrhosis, is associated with reduced CRF and poorer hemodynamic performance during CPX. Prioritizing exercise training for those in earlier stages (F3) may prevent fitness decline, which could hinder physical training and liver transplantation candidacy.

Preoperative Cardiac Assessment for Coronary Artery Disease: From Symptoms to Angiography

Although cardiovascular anesthesiologists play a role in the multidisciplinary heart team, they are generally not involved prior to the diagnosis of coronary artery disease. This work was designed to broadly cover the factors influencing decision-making when proceeding with coronary angiography in a patient with suspected coronary artery disease. The authors cover the principles, rationale, benefits, and downsides of common tests involved.

A reference equation for peak oxygen uptake for cycle ergometry in Chinese adult participants

Accurately quantifying cardiorespiratory fitness (CRF) through cardiopulmonary exercise testing (CPET) is increasingly important for improving risk assessment and guiding clinical decisions. However, research on V̇O2peak reference values and predictive equations for the Chinese population remains limited. This study aimed to establish a V̇O2peak predictive equation for Chinese adults. This study analyzed healthy participants who underwent CPET at Peking University Third Hospital (PUTH) from September 1, 2017, to September 1, 2023. Data from September 1, 2017, and August 31, 2021 were used as the derivation cohort, and September 1, 2021, to September 1, 2023 were utilized as an external validation cohort for temporal validation. The derivation cohort underwent backward multivariate regression analysis to generate the V̇O2peak prediction equation, which was compared with the widely-used Wasserman, FRIEND and Xiangya equations. The PUTH derivation cohort (N = 4531, mean age: 50.7 years, 18-88 years) and validation cohort (N = 4624, mean age: 46.1 years, 18-89 years) included 48.8 and 48.5% men, respectively. With increasing age, both men and women V̇O2peak exhibited a general decline. The predictive equation for V̇O2peak was established based on the derivation cohort: V̇O2peak (mL·min-1) =  -24364.9 - 621.3 × Sex (Women = 1, Men = 2) -10.7 × Age + 0.2 × Height2 (cm) + 6464.7 × Log(BMI) -24997.2 × Log(BSA) +12388.6 × Log(LBM) (adjusted R2 = 0.624, p < 0.001). It demonstrated higher consistency between measured and predicted results compared to Xiangya, Wasserman, and FRIEND equations. This study presents the PUTH equation, a new V̇O2peak prediction equation for Chinese adults. Compared to existing equations, the PUTH equation shows reduced bias and improved accuracy, providing a more reliable tool for assessing CRF and guiding clinical interventions in the Chinese population.

Effect of heart rate, correlated colour temperature and illuminance on human visual perception under LED lighting environments

Lighting environments with different correlated colour temperatures (CCTs) and illuminance levels not only give different subjective perceptions but also affect physiological parameters. However, previous studies have rarely considered the interaction between participants' physiological state and psychological feelings under different lighting environments. To address this gap, this study aimed to investigate the impact of different CCTs (6500 K and 3000 K) and illuminances (300 lx and 900 lx) on participants' visual perception, considering heart rate changes as a key variable. Through physiological and psychological questionnaire assessments, it was found that changes in heart rate significantly influenced participants' subjective evaluations. Heart rate variations affected participants' physiological perception of the lighting environment, such as respiration and thermal sensation. The results of this study can be used as a reference for future indoor lighting design, providing a scientific basis for creating a more comfortable and efficient lighting environment.

The effects of eccentric cycling on vascular reactivity

Purpose

Eccentric cycling has gained attention as a novel exercise modality that increases muscle performance at lower metabolic demand, which could enhance cardiovascular rehabilitation. However, endothelial function response to eccentric cycling (ECC) has yielded contradictory results. Therefore, the purpose of this study was to determine the effect of 30 min of moderate-intensity cycling ECC on endothelial function.

Methods

A total of 15 (9 females, 6 males) young, apparently healthy participants were recruited for two laboratory visits. First, a maximum oxygen consumption (VO2max) and blood lactate (BLa) threshold were measured to determine moderate workload intensity, followed by a familiarization stage on an ECC ergometer. During the second visit, a 30-min of moderate ECC was performed 72 h after the first visit. Endothelial function was measured via Flow-Mediated Dilation (FMD) pre- and post-exercise bout. FMD was calculated following traditional recommendations and adjusting for exercise-induced endothelial shear stress (ESS), utilizing the same pre-exercise baseline artery diameter for post-exercise FMD calculations.

Results

There was a significant increase in endothelial function (p = 0.037) when adjusting pre-exercise baseline diameter to adjust for ESS, but when utilizing the traditional method no change in endothelial function was observed.

Conclusion

30-min of moderate ECC showed a significant improvement in endothelial function when accounting for exercise-induced ESS. These results support the use of the pre-exercise baseline diameter when calculating post-exercise FMD to avoid the exercise-induced ESS or muscle metabolites effects on post-exercise artery diameter.

Deep learning analysis of exercise stress electrocardiography for identification of significant coronary artery disease

Background

The diagnostic power of exercise stress electrocardiography (ExECG) remains limited. We aimed to construct an artificial intelligence (AI)-based method to enhance ExECG performance to identify patients with significant coronary artery disease (CAD).

Methods

We retrospectively collected 818 patients who underwent both ExECG and coronary angiography (CAG) within 6 months. The mean age was 57.0 ± 10.1 years, and 614 (75%) were male patients. Significant coronary artery disease was seen in 369 (43.8%) CAG reports. We also included 197 individuals with normal ExECG and low risk of CAD. A convolutional recurrent neural network algorithm, integrating electrocardiographic (ECG) signals and features from ExECG reports, was developed to predict the risk of significant CAD. We also investigated the optimal number of inputted ECG signal slices and features and the weighting of features for model performance.

Results

Using the data of patients undergoing CAG for training and test sets, our algorithm had an area under the curve, sensitivity, and specificity of 0.74, 0.86, and 0.47, respectively, which increased to 0.83, 0.89, and 0.60, respectively, after enrolling 197 subjects with low risk of CAD. Three ECG signal slices and 12 features yielded optimal performance metrics. The principal predictive feature variables were sex, maximum heart rate, and ST/HR index. Our model generated results within one minute after completing ExECG.

Conclusion

The multimodal AI algorithm, leveraging deep learning techniques, efficiently and accurately identifies patients with significant CAD using ExECG data, aiding clinical screening in both symptomatic and asymptomatic patients. Nevertheless, the specificity remains moderate (0.60), suggesting a potential for false positives and highlighting the need for further investigation.

Cardiopulmonary exercise capacity markers and their link to symptom burden in patients at risk for heart failure with non-reduced ejection fraction

The American Heart Association (AHA) guidelines assess heart failure (HF) via comorbidities, laboratory markers, and echocardiography, while the New York Heart Association (NYHA) classification evaluates functional capacity. The primary objective of this study was to investigate the correlation between objectified HF-related symptoms and cardiac and muscular exercise capacity in Stage B HF patients with non-reduced ejection fraction. As secondary endpoints, we stratified this analysis for subgroups of NYHA classes to evaluate the primary endpoint for different levels of impairment and for sex to address for differences between men and women. Sixty-two Stage B HF patients with non-reduced EF were screened from an HF-risk cohort. Assessments included medical history, HF-related symptoms (Kansas City Cardiomyopathy Questionnaire, KCCQ), physical examination, laboratory tests, echocardiography, and cardiopulmonary exercise testing (CPET) with cardiac output monitoring. Correlations were analyzed between KCCQ score and exercise capacity markers: maximal oxygen uptake (VO2max), arterio-venous oxygen difference (avDO2), cardiac power output (CPO), mean arterial pressure (MAP), and respiratory efficiency (Ve/VO2). Subgroup analyses were performed by sex and NYHA class determined by VO2max or KCCQ functional scores. Our HF patient cohort showed reduced KCCQ scores (78.3) and VO₂max (22.9 ml/kg/min), and a progressed reduction in avDO₂. In the total cohort, KCCQ scores showed moderate correlations with Ve/VO₂ (r = -0.39) and MAP (r = 0.27). NYHA stratification by VO₂max revealed differences in avDO₂ and cardiac output but not KCCQ scores, while KCCQ-functional stratification only showed differences in Ve/VO₂. Sex-specific analysis showed KCCQ scores correlated with CPO in men (r = 0.65) and Ve/VO2 in women (r = -0.68). Our identified Stage B HFpEF cohort showed already alterations in total, cardiac and muscular exercise limitation. The HF symptom severity was weakly associated to the higher blood pressure and ventilatory inefficiency and, but moderately to strongly correlated CPO in men and Ve/VO2 in women in sex-specific analyses.

Blood pressure changes during different methods of resistance training in normotensive and stage 1 hypertensive individuals: a repeated measures cross-sectional study

BACKGROUND

Stage 1 hypertension influences acute cardiovascular responses to resistance exercises and post-exercise recovery. We examined whether the order of exercises, particularly in agonist-antagonist pairings, can alter these cardiovascular responses. This study compares systolic and diastolic blood pressure responses during agonist and agonist-antagonist paired sets of upper and lower-body resistance exercises with a load of 75% repetition maximum in individuals with normotension and stage 1 hypertension.

METHODS

A cross-sectional study enrolled 47 participants with sedentary jobs, comprising 30 normotensive individuals (47.8 ± 5.9 years, height 174.8 ± 10.2 cm, weight 77.7 ± 15.4 kg, BMI 25.3 ± 3.6 kg/m2) and 17 hypertensive individuals (54.3 ± 6.0 years, 177.6 ± 11.3 cm, 89.8 ± 16.4 kg, BMI 28.5 ± 4,5 kg/m2). Acute cardiovascular parameters were measured using an arteriograph, a non-invasive device designed to assess vascular stiffness and cardiovascular health, after each set of resistance training.

RESULTS

No significant differences in systolic blood pressure changes were found between the resistance training methods and aerobic exercise when comparing normotensive and hypertensive individuals. However, significant increases in systolic blood pressure were observed during lower-body exercises (11.3-24.7 mmHg for normotensives and 11.7-24.1 mmHg for hypertensives, p < 0.05). Hypertensive individuals showed slightly higher increases during lower-body supersets (p < 0.05). Regarding diastolic blood pressure, significant decreases were noted during upper-body resistance training for both groups, especially for normotensives (-10.6 to -13.7 mmHg, p < 0.05).

CONCLUSIONS

Agonist and agonist-antagonist paired set resistance training for both lower and upper-body exercises resulted in similar blood pressure changes in individuals with normotension and stage 1 hypertension. These findings suggest that both methods may have comparable cardiovascular effects across blood pressure.

TRIAL REGISTRATION

The study was registered on ClinicalTrials.gov (NCT06047678). Registration date: 31 August 2023.

Mechanisms of exercise intolerance in heart failure with preserved ejection fraction (HFpEF)

Exercise intolerance is a well-established symptom of heart failure with preserved ejection fraction (HFpEF) and is associated with impaired quality of life and worse clinical outcomes. Historically attributed to diastolic dysfunction of the left ventricle, exercise intolerance in HFpEF is now known to result not only from diastolic dysfunction, but also from impairments in left ventricular systolic function, left atrial pathology, right ventricular dysfunction, and valvular disease. Disorders of heart rate and rhythm such as chronotropic incompetence and atrial fibrillation have also been implicated in exercise intolerance in this population. Pathologic changes to extra-cardiac organ systems including the respiratory, vascular, hormonal, and skeletal muscle systems are also thought to play a role in exercise impairment. Finally, comorbidities such as obesity, inflammation, and anemia are common and likely contributory in many cases. The role of each of these factors is discussed in this review of exercise intolerance in patients with HFpEF.

Can Infrared Thermal Imaging Reflect Exercise Load? An Incremental Cycling Exercise Study

Monitoring the training load is crucial in sports science research, as it provides scientific evidence for assessing training effects, optimizing athletic performance, and preventing overtraining by quantifying both external and internal loads. Although traditional monitoring methods have made significant progress, infrared thermography (IRT) technology, with its non-contact, real-time, and non-invasive characteristics, is gradually emerging as an effective tool for evaluating the relationship between the training load and physiological responses. This study evaluated 31 healthy male adults (age 21.9 ± 2.7 years, weight 75 ± 8.26 kg, and training duration 240 ± 65 min/week) performing incremental exhaustive exercise on a cycle ergometer (with a 60W starting load, increasing by 20W per minute). Entropy analysis was used to quantitatively assess the surface radiation patterns of regions of interest (forehead, chest, and abdomen) obtained through thermal imaging. Compared to baseline, significant differences in the surface radiation patterns of the regions of interest were observed at the point of exhaustion (p ≤ 0.01). Correlation analysis revealed strong associations between the external load, oxygen consumption, and chest temperature entropy (r = 0.973 and 0.980). Cluster analysis of the chest entropy, external load, and oxygen consumption showed a non-linear increasing trend in their inter-relationships. Further individual analysis demonstrated positive correlations between the percentage increase in the chest entropy and both the external load (r = 0.70-0.98) and oxygen consumption (r = 0.65-0.97). Entropy analysis offers a new approach for quantitatively assessing surface radiation patterns from infrared thermography, and reveals the coupling relationship between thermoregulation and metabolic responses during exercise.

Patterns of systolic blood pressure response at the end of exercise and mortality and morbidity in patients referred for exercise testing

OBJECTIVES

Peak exercise systolic blood pressure (SBP) is associated with future cardiovascular disease (CVD) and mortality. We aimed to evaluate the predictive value of different SBP patterns at the end of exercise with these outcomes.

METHODS

We studied 6329 adults (45% women) referred for exercise testing, with test duration of 6-14 min, maximal effort and valid SBP measurements at the end of exercise. The two last SBPs were indexed to work rate (mmHg/Watt), defining responses as: drop (negative change), plateau (no change), slow (lower tertile of increase), intermediate (middle tertile) and steep (upper tertile). Data were cross-linked with nationwide disease and mortality registries. Associations with all-cause mortality and incident CVD were analysed using Cox proportional hazards regression (hazard ratio (HR), 95% confidence interval), using slow SBP increase as reference, adjusted for sex, age, body mass index, baseline CVD (mortality analysis only), beta-blockers and exercise capacity (peak Watt).

RESULTS

The prevalence of SBP responses at the end of exercise were drop (1.1%), plateau (15.0%), slow (30.4%), intermediate (25.2%) and steep increase (28.3%). Follow-up was 8.8±3.4 years. Compared with a slow increase, the adjusted all-cause mortality risks were not statistically different for a drop (HR 1.16 (0.50-2.65)), plateau (HR 1.19 (0.85-1.66)), intermediate (HR 1.24 (0.93-1.66)) or steep SBP increase (HR 1.16 (0.89-1.52)). CVD risk was increased in those with a SBP drop (HR 3.10 (1.85-5.19), but not significantly for plateau (HR 1.17 (0.92-1.48)), intermediate or steep SBP increases (HRs 0.99-1.00).

CONCLUSION

Subjects with a slow SBP increase at the end of exercise tended to have the lowest mortality risk, although no SBP response pattern predicted all-cause mortality independently. CVD risk was strongly increased in patients with a drop in SBP and tended to be increased (non-significantly) also in patients with a plateau in SBP at the end of exercise, in comparison with increasing SBP.

Combined arm-leg endurance training vs. leg endurance training in patients with an implantable cardioverter defibrillator: A randomized controlled study

BACKGROUND

There is a lack of evidence regarding the effect of combining arm and leg training on arm exercise capacity, upper extremity functionality and safety in patients with implantable cardioverter-defibrillators (ICDs).

OBJECTIVE

The aim of this study was to compare the effects of combined arm-leg endurance training (ETarm+leg) with leg endurance training (ETleg) alone on arm exercise capacity, cardiorespiratory fitness, and safety issues in patients with ICDs.

METHODS

In this prospective randomized controlled study, 24 caucasian patients with an ICD (NYHA class II-III, mean age: 59.38±11.54 years, 20 male, 4 female) underwent cardiopulmonary exercise testing (CPET) and arm ergometry. The ETleg intervention consisted of cycle ergometer training for 40 min at workload of 70-80 % of peak oxygen consumption (VO2peak). The ETarm+leg intervention also included arm ergometer training for 20 min at 60 % peak workload (Wpeak). Both exercise programs were performed for a total of 30 sessions (5 days for 6 weeks). Quade's non-parametric covariance analysis was performed for changes between groups by adjusting before treatment.

RESULTS

Significant increases in time to reach VO2peak (min), VO2peak (L), VO2peak/kg (L/kg/min), VO2peak (%), Wpeak, and test duration during arm ergometry were observed in the ETarm+leg group (p < 0.05). No shocks or ventricular tachycardia/fibrillation episodes were recorded.

CONCLUSIONS

ETarm+leg had a more pronounced effect on cardiopulmonary exercise capacity and arm exercise capacity in patients with ICDs. Arm exercise training is safe in terms of ICD parameters and should be incorporated into cardiac rehabilitation for patients with ICDs.

A cardiac rehabilitation programme based on neuromuscular training improves the functional capacity of patients with acute coronary syndrome: a preliminary randomised controlled trial

OBJECTIVES

To evaluate the effects of a cardiac rehabilitation programme based on neuromuscular training (NMT) compared with classic rehabilitation strength training (CRST) in patients diagnosed with acute coronary syndrome (ACS).

DESIGN

Preliminary randomised, double-blinded, parallel clinical trial.

SETTING

University health clinic in Valencia, Spain.

PARTICIPANTS

Thirty patients with ACS.

INTERVENTIONS

Patients were assigned to one of two groups at random: the NMT group (n = 15) and the CRST group (n = 15). All patients attended the 20 sessions of the exercise programme.

MAIN OUTCOME MEASURES

The primary outcome was the Incremental Shuttle Walk Test (ISWT). The secondary outcomes were the Chester Step Test (CST), the 30-Second Chair Stand Test (30CST), and hip flexor dynamometry. Assessments were made at baseline, immediately post-treatment, and at 6-month follow-up.

RESULTS

The NMT group showed a greater improvement in the ISWT than the CRST group, both at post-treatment {mean 648 [standard deviation (SD) 197] vs 493 (SD 219), mean difference 155, 95% confidence interval (CI) -1 to 310} and at follow-up [732 (SD 183) vs 518 (SD 222), mean difference 214, 95% CI 61 to 367]. The secondary outcomes showed significant between-group differences in favour of the NMT group at 6-month follow-up, except for the 30CST.

CONCLUSIONS

These preliminary findings indicate that a cardiac rehabilitation programme based on NMT may improve functional capacity in terms of patient performance, cardiorespiratory fitness and muscle strength. Moreover, the improvements were maintained at medium-term follow-up. This could help improve the design of rehabilitation sessions, considering factors associated with performing everyday activities in patients affected by ACS.

CLINICAL TRIAL REGISTRATION NUMBER

NCT04246008. CONTRIBUTION OF THE PAPER.

Significance of Coronary Artery Calcifications and Ischemic Electrocardiographic Changes Among Patients Undergoing Myocardial Perfusion Imaging

BACKGROUND

Estimation of coronary artery calcification (CAC) can provide important prognostic information in patients with suspected coronary artery disease.

OBJECTIVES

The authors aimed to investigate whether CAC evaluation offers additional insight into the association of stress electrocardiographic (ECG) changes with adverse outcomes in patients undergoing myocardial perfusion imaging (MPI).

METHODS

A total of 12,265 patients (47% female, median: 64 (56-73) years, body mass index: 29 ± 7 kg/m2) who underwent exercise treadmill or regadenoson single-photon emission computed tomography/computed tomography (CT) MPI during June 2016 to May 2022 at a large academic center were retrospectively studied.

RESULTS

During the median follow-up of 1.6 (IQR: 0.5-3.0) years, the primary outcome (3-year composite of death, myocardial infarction, or coronary revascularization, major adverse cardiac event [MACE]) occurred in 1,422 patients. Within participants with normal perfusion, MACE rate was the highest in patients with CAC with or without ischemic stress ECG (9.6% and 7%, respectively), and low event rates were observed in patients without CAC with or without ischemic stress ECG (0.5% and 1.9% respectively). In a subgroup analysis, all CAC grades (mild, moderate, severe) were independently associated with worse 3-year composite endpoint rates. In multivariable analysis, the presence of CAC was associated with MACE independent of ischemic ECG changes in both the overall cohort (P < 0.001) and when restricting the analysis to patients with normal perfusion (P < 0.05).

CONCLUSIONS

In patients with normal single-photon emission computed tomography/CT MPI, CAC is strongly associated with adverse outcomes independent of ischemic ECG changes with low event rates in patients without CAC on attenuation CT irrespective of ischemic stress ECG changes.

Heart Rate Index-An Alternative Exercise-Based Equation for Estimating Peak VO 2

PURPOSE

Heart rate (HR)-derived variables (HR reserve [HR peak  - HR rest ], chronotropic indices [attenuated HR response to exercise], HR recovery [attenuated HR response to exercise recovery], and peak HR index [HR peak /HR rest ]) together with peak oxygen uptake (VO 2peak ) are potential prognostic variables for cardiovascular and all-cause mortality. However, heart rate index (HRI) has not been established as a surrogate for VO 2peak , whether measured (Meas) or estimated (Est), during cycle ergometry (CE) and/or treadmill testing (TT).

METHODS

HR-derived prognostic variables to assess cardiovascular outcomes were identified from 150 studies obtained from MEDLINE and Google Scholar searches. The Meas CE/TT-VO 2peak was reported in 81 studies (21 773 participants) and Est CE/TT-VO 2peak in 69 studies (331 435 participants). Using the HRI equation with metabolic equivalent (METs) = 6 × HRI - 5 (where HRI = peak HR/resting HR), HRI-VO 2peak was calculated from HR data reported in the 150 studies. The HRI-VO 2peak was then compared against group mean data for both Meas CE/TT-VO 2peak and Est CE/TT-VO 2peak .

RESULTS

The difference between Meas CE/TT-VO 2peak and HRI-VO 2peak was 1% (7.15 ± 3.25 METs vs 7.08 ± 3.02 METs [ P = .833], respectively). By comparison, the difference between Est CE/TT-VO 2peak and HRI-VO 2peak was 25.6% (8.94 ± 2.36 METs vs 7.12 ± 2.27 METs [ P < .001], respectively). Moreover, HRI equation estimation of VO 2peak showed greater overprediction for TT, 26.6%, than for CE, 11.9%.

CONCLUSIONS

The Meas-VO 2peak and HRI-VO 2peak agreed closely. When compared with HRI-VO 2peak , Est-VO 2peak from currently used exercise-based equations shows significant overprediction. Use of HRI and/or Fitness Registry and the Importance of Exercise National Database (FRIEND) registry equations warrant consideration for more accurately estimating VO 2peak .

Effect of physical exercise training on neural activity during working memory in major depressive disorder

BACKGROUND

Deficits in working memory (WM) are common in patients with Major Depression Disorder (MDD). Previous research mainly in healthy adults indicated that physical exercise training may improve cognitive functions by stimulating neuronal plasticity particularly in hippocampal structures. Thus, the goal of this functional Magnetic Resonance Imaging (fMRI) study was to examine alterations in neuronal activity during a WM task and to investigate changes in brain volume and functioning following a physical exercise training in patients with MDD with a specific focus on hippocampal structures.

METHODS

86 (39 female) MDD outpatients (average age 37.3), diagnosed by clinical psychologists, were randomly assigned to one of three groups for a 12-week intervention: High intensity exercise training (HEX), low intensity exercise training (LEX) or waiting list control group (WL). An n-back task (with WM loads of 0, 1, 2, and 3) during fMRI was conducted before and after interventions/waiting period.

RESULTS

Both exercise groups showed better performance and shorter reaction times at higher WM loads after 12-weeks of physical exercise training. Specifically in the HEX, we found an improvement in physical fitness and an increase in neural activation in the left hippocampus as compared to the WL following the exercise training. Training-related structural volume changes in gray matter or hippocampus were not detected.

CONCLUSIONS

Our results partly support the hypothesis that physical exercise training positively affects WM functions by improving neuronal plasticity in hippocampal regions. Exercise training seems to be a promising intervention to improve deficient WM performance in patients with MDD.

CLINICAL TRIALS REGISTRATION NAME

Neurobiological correlates and mechanisms of the augmentation of psychotherapy with endurance exercise in mild to moderate depression - SPeED, http://apps.who.int/trialsearch/Trial2.aspx?TrialID=DRKS00008869, DRKS00008869.

Effects of 6 months of endurance exercise on motor function, exercise capacity, and autonomic function based on presence of autonomic dysfunction in individuals with early Parkinson's disease

BackgroundEndurance exercise improves aerobic capacity (VO2peak) and motor symptoms in people with early Parkinson's disease (PD). Some people with PD exhibit signs of chronotropic incompetence (CI), which may impact exercise-induced benefits.ObjectiveWe investigated whether CI in people with early PD influences the change in motor signs, VO2peak, and peak heart rate (HR) following 6 months of endurance exercise.MethodsWe performed secondary analyses of the Study in Parkinson's Disease of Exercise (SPARX), which randomized people with early PD into a high-intensity endurance exercise [80-85% of peak HR], moderate-intensity endurance exercise [60-65% of peak HR], or usual care group. MDS-UDPRS Part 3 score, VO2peak, and heart rate (HR) response to maximal cardiopulmonary exercise testing (CPET) were analyzed at baseline and following 6 months of exercise. Participants were divided into three groups: 1) normal chronotropic response at baseline, 2) CI at baseline, and 3) taking medications with a known negative chronotropic effect regardless of CI status.ResultsData from 119 individuals (64.0 ± 9.0 years, 57.1% male, 0.3 years since diagnosis [median]) were analyzed. There were no differences among the groups in change in MDS-UPDRS motor score (p = 0.953), VO2peak (p = 0.965), or peak HR (p = 0.388). People randomized into the high-intensity group improved VO2peak compared to usual care (p < 0.001adj) regardless of CI status.ConclusionsBaseline CI did not alter responses to endurance exercise in those with early PD, suggesting that the beneficial effects of endurance exercise on disease progression and VO2peak in people with early PD apply equally to people with CI.

Comparison of Traditional and Intensive Cardiac Rehabilitation on Dietary Behavior and Clinical Risk Factor Outcomes: Secondary Analysis Research

PURPOSE

The objective of this study was to assess differences in dietary behavior and clinical risk factor outcomes and explore predictors of change among patients participating in traditional and Pritikin intensive cardiac rehabilitation (CR).

METHODS

This secondary analysis of cardiac registry data from 2015 to 2021 included patients participating in traditional CR (n = 420) or Pritikin intensive CR (n = 1005) at a single hospital site. Dietary behavior outcomes included the Rate Your Plate measure, while clinical risk factor outcomes included fasting lipids, blood pressure, anthropometrics, functional outcomes, and psychosocial assessment. Analysis of covariance examined a difference in Rate Your Plate scores between CR groups. Multivariate analysis of covariance was used to determine differences in clinical risk factor variables between CR groups. Predictors of change in dietary behavior and clinical risk factors were determined through multiple bivariate linear regression models within each CR group.

RESULTS

Both CR programs led to significant improvements though more change was observed among Pritikin intensive CR participants in dietary behavior, anthropometrics, and fasting lipids. Status as a current or recent smoker was not a significant predictor of dietary behavior. Male sex, status as a current or recent smoker, beta-blockers, and angiotensin-converting enzyme inhibitors prescribed were not significant predictors of total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, or non-high-density lipoprotein cholesterol for traditional and Pritikin intensive CR groups. There were not significant predictors of blood pressure, body mass, or waist circumference.

CONCLUSION

Although participation in either CR program yielded cardiometabolic benefits, Pritikin intensive CR patients exhibited significantly greater improvements in dietary behavior and clinical risk factors.

The effect of resistance training on blood pressure and resting heart rate in type 2 diabetes: A systematic review and meta-analysis of randomized controlled trials

This meta-analysis assessed the impacts of resistance training on hemodynamic outcomes, including blood pressure and heart rate, in patients with type 2 diabetes (T2D). Four databases were searched following PRISMA guidelines. Randomized controlled trials (RCTs) comparing resistance training to usual care were included if they evaluated systolic and diastolic blood pressure (SBP and DBP), heart rate, and maximum oxygen uptake (VO2max) in adults with T2D. Random-effects models were used to calculate mean differences, with corresponding 95 % confidence intervals (CIs). Twenty-six RCTs were included. Resistance training significantly reduced SBP by -4.13 mmHg (95 % CI: -6.40, -1.85; p = 0.0004) and DBP by -2.03 mmHg (95 % CI: -3.69, -0.38; p = 0.02), with greater reductions in interventions lasting over 12 weeks. Resting heart rate decreased by -3.17 bpm (95 % CI: -6.33, -0.01; p = 0.05) and VO2max improved by 0.27 ml/kg/min (95 % CI: 0.02, 0.53; p = 0.04). Meta-regression revealed that intervention duration, session frequency, and study quality did not significantly explain the observed heterogeneity. Resistance training effectively improves hemodynamic outcomes T2D patients, but high heterogeneity in blood pressure outcomes and limited subgroup data on specific subgroups (e.g., women) restrict generalizability. Further research should explore heterogeneity sources and optimize resistance training protocols.

Psychometric properties of the Spanish Multidimensional Fatigue Inventory in people with heart diseases

BACKGROUND

Fatigue is one of the most limiting symptoms in individuals with heart disease (HD). However, valid and reliable instruments for assessing fatigue in clinical practice still need to be improved.

OBJECTIVE

To assess the dimensional structure of the self-reported Spanish Multidimensional Fatigue Inventory (MFI) and analyze its psychometric properties in individuals with HD.

METHODS

A longitudinal observational study included 247 participants (age 57.71 years; 23.9 % women; 89.9 % Caucasian). Test-retest reliability was assessed 10-14 days after the first evaluation. Measures evaluating fatigue, health-related quality of life (HRQoL), and functional capacity were collected to assess convergent validity. Acceptability, practicality, construct validity, floor/ceiling effects, internal consistency, and measurement error were also calculated.

RESULTS

Confirmatory factor analysis supported the 4-factor structure of the MFI and the deletion of 3 items for its application in individuals with HD. The 17-item version showed no floor-ceiling effects and exhibited excellent internal consistency (Cronbach's α = 0.90) and test-retest reliability (Intraclass Correlation Coefficient (ICC) = 0.94). While all subscales demonstrated adequate internal consistency (Cronbach's α > 0.70) and good to excellent test-retest reliability (ICC, 0.75 - 0.91), the reduced motivation subscale showed slightly lower internal consistency. The minimal detectable change was 9.5 points for the total score. Convergent validity was established through moderate-strong correlations with fatigue, HRQoL, and functional capacity measures (r = |0.320-0.729|).

CONCLUSIONS

The shortened version of the Spanish MFI (MFI-17) is a valid and reliable tool for quantifying fatigue in individuals with HD, supporting its clinical and research applicability.

Effects of high-intensity interval training on cardiorespiratory function in coronary artery disease: An overview of systematic reviews

BACKGROUND

Exercise-based cardiac rehabilitation has been identified as a crucial component in mitigating all-cause mortality among individuals diagnosed with coronary artery disease (CAD). Nevertheless, the optimal exercise prescription remains elusive.

OBJECTIVE

The purpose of this overview is to conduct a systematic evaluation and synthesis of the evidence derived from systematic reviews/meta-analyses (SRs/MAs) regarding the effects on cardiorespiratory fitness and safety of high-intensity interval training (HIIT) compared to moderate-intensity continuous training (MICT) for CAD.

METHODS

SRs/MAs were searched across 5 databases from inception until March 22, 2023. We assessed methodological quality using the Assessing the Methodological Quality of Systematic Reviews 2 (AMSTAR-2). The risk of bias, reporting, and evidence were evaluated using the Risk of Bias in Systematic Reviews (ROBIS) tool, the Preferred Reporting Item for Systematic Review and Meta-analysis (PRISMA) 2020, and the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system, respectively.

RESULTS

In total, 9 SRs/MAs were included. Based on the AMSTAR-2 criteria, 4 and 5 studies were considered low- and critically-low quality, respectively. None of the studies reported all 27 items outlined in the PRISMA 2020 checklist. Regarding the ROBIS evaluation, 4 reviews were rated as low risk, 4 as high risk, and 1 as unclear risk. The GRADE evaluation indicated 3 high-level evidence, 20 moderate-level evidence, 28 low-level evidence, and 34 very low-level evidence studies based on 85 indicators. Moderate- to high-quality evidence supported that HIIT is superior to MICT in improving VO2peak for CAD.

CONCLUSION

The efficacy and time cost of developing cardiorespiratory fitness support HIIT as an adjunct or alternative to MICT. The evidence does not permit a definitive decision regarding the adverse effects of HIIT compared to MICT. Because of the insufficient quality of the evidence, future studies should focus more on the quality of randomized controlled trials and evidence for SRs/MAs to provide scientific and robust evidence for conclusions.

TRIAL REGISTRATION

The review was registered at PROSPERO: CRD42023420015.

Feasibility and acceptance of transdermal auricular vagus nerve stimulation using a TENS device in females suffering from long COVID fatigue

BACKGROUND

The COVID-19 pandemic has led to significant health challenges, with some individuals developing long COVID characterized by persistent symptoms such as fatigue, dyspnea and cognitive difficulties lasting weeks or months after infection. This condition predominantly affects women and may involve prolonged inflammation and autonomic nervous system dysfunction. Current treatments focus on symptom relief and vagus nerve stimulation (VNS) is being investigated for its potential therapeutic benefits.

METHODS

This pilot study was a prospective, blinded, randomized controlled trial involving 36 female long COVID patients aged 18-70 years. Participants were assigned to three groups receiving VNS at frequencies of 10 Hz, 25 Hz, or a control of 2 Hz for 3 months. Outcomes were assessed at baseline, after 4 and 12 weeks.

RESULTS

The study revealed that all VNS treatment groups experienced reduction in symptoms associated with long COVID, particularly in fatigue and dyspnea, after 12 weeks. Participants across all frequencies reported an improvement in health-related quality of life. Heart rate variability remained stable throughout the trial, and no significant changes in morning salivary cortisol levels were seen across groups.

DISCUSSION

Vagus nerve stimulation may offer therapeutic benefits for women with long COVID, particularly in reducing fatigue and dyspnea. The treatment was found to be safe, with no significant side effects reported; however, further research with larger study groups is needed to confirm these findings and examine the long-term effects of VNS on autonomic nervous system function.

Independent influence of type 2 diabetes on reduced cardiopulmonary fitness in patients after percutaneous coronary intervention: a cross-sectional study

Previous studies have found a significant association between type 2 diabetes (T2DM) and impaired cardiopulmonary fitness (CRF); however, little evidence was shown in patients after percutaneous coronary intervention (PCI). This study aimed to evaluate the independent effects of T2DM on CRF in patients who have undergone successful percutaneous coronary intervention (PCI) and received guideline-directed medical therapy. Additionally, we explored whether this association is influenced by factors such as demographic features, physical activity level, duration of diabetes, time from index PCI, and history of occlusion myocardial infarction. We retrospectively analyzed data from post-PCI patients who consecutively visited the Cardiac Rehabilitation Center at Beijing Anzhen Hospital between September 2023 and July 2024. To isolate the impact of T2DM on cardiovascular fitness, we implemented strict exclusion criteria for confounding comorbidities, particularly heart failure. Cardiorespiratory fitness was quantified through gold-standard measures: peak oxygen uptake (VO2max) and metabolic equivalents (METs). Baseline characteristics were compared between patients with T2DM and non-diabetic patients (DM group vs. non-DM group). A multivariable regression model was used to evaluate the independent effect of T2DM on CRF, adjusting for confounding factors such as demographic features, physical activity level, duration of diabetes, time since index PCI, and residual comorbidities. Subgroup analyses and interaction tests were performed to assess the impact of T2DM across different subgroups. 201 patients (150 non-DM and 51 DM patients) were included in the final analysis. Hypertension was significantly more prevalent in DM patients (68.6 vs. 42.7%, p = 0.001), while other comorbidities, anthropometric measurements, lifestyle factors, and time from index PCI showed no significant differences between groups (all p > 0.05). Multivariate logistic regression analyses demonstrated significant negative associations between T2DM and both VO2max and METs. After adjusting for basic demographic and lifestyle factors (Model 1), T2DM was inversely associated with VO2max (β=-98.3, 95% CI -193.4 to -3.3, p = 0.044) and METs (β=-0.4, 95% CI -0.8 to -0.0, p = 0.05). These negative associations remained robust and became stronger in Model 2, which further adjusted for physical activity status, hypertension, hyperlipidemia, history of occlusion myocardial infarction, time from index PCI, DM duration, and using beta-blockers, showing more pronounced inverse relationships with both VO2max (β=-212.3, 95% CI -389.4 to -35.3, p = 0.02) and METs (β=-0.9, 95% CI -1.6 to -0.2, p = 0.014). Subgroup analyses indicated consistent inverse associations, with no significant effect modification based on sex, age, body mass index (BMI), time since the index PCI, physical activity status, or a history of occlusion myocardial infarction. Our study demonstrates that T2DM is an independent negative predictor of CRF in post-PCI patients, with consistent findings across various subgroups and robust results after adjusting for confounding factors. These findings underscore the importance of CRF assessment in post-PCI patients and highlight the need for targeted interventions to improve CRF in individuals with T2DM.

Abbreviated Duke Activity Status Index for Risk Stratification in Heart Failure

The Duke activity status index (DASI), a self-administered 12-item questionnaire has been used to estimate functional capacity and recently demonstrated prognostic information. We aimed to develop an abbreviated version for clinical applications. Leveraging the Cleveland Clinic GeneBank Study, we developed an abbreviated DASI questionnaire (aDASI) with the machine learning XGBoost algorithm, with the goal of maintaining the accuracy and reliability of the original DASI. We validated the prognostic value of aDASI in a subset of patients with heart failure from GeneBank and an independent data set from the GUIDE-IT (Guiding Evidence Based Therapy Using Biomarker Intensified Treatment in Heart Failure; ClinicalTrials.gov NCT01685840) trial. The results confirmed the congruence and accuracy between the original and the abbreviated scores while reducing the number of questions (R = 0.97, p <0.001). The original DASI score and the aDASI exhibited a strong correlation in the GeneBank and predictive value for all-cause mortality at different time points in the GUIDE-IT cohort. In conclusion, the abbreviated DASI tracks with original DASI assessment and performs comparably to the original DASI questionnaire in predicting all-cause mortality.

Laboratory comparison of consumer-grade and research-established wearables for monitoring heart rate, body temperature, and physical acitivity in sub-Saharan Africa

Background

Consumer-grade wearables are becoming increasingly popular in research and in clinical contexts. These technologies hold significant promise for advancing digital medicine, particularly in remote and rural areas in low-income settings like sub-Saharan Africa, where climate change is exacerbating health risks. This study evaluates the data agreement between consumer-grade and research-established devices under standardized conditions.

Methods

Twenty-two participants (11 women, 11 men) performed a structured protocol, consisting of six different activity phases (sitting, standing, and the first four stages of the classic Bruce treadmill test). We collected heart rate, (core) body temperature, step count, and energy expenditure. Each variable was simultaneously tracked by consumer-grade and established research-grade devices to evaluate the validity of the consumer-grade devices. We statistically compared the data agreement using Pearson's correlation r, Lin's concordance correlation coefficient (LCCC), Bland-Altman method, and mean absolute percentage error.

Results

A good agreement was found between the wrist-worn Withings Pulse HR (consumer-grade) and the chest-worn Faros Bittium 180 in measuring heart rate while sitting, standing, and slow walking on a treadmill at a speed of 2.7 km/h (r ≥ 0.82, |bias| ≤ 3.1 bpm), but this decreased with increasing speed (r ≤ 0.33, |bias| ≤ 11.7 bpm). The agreement between the Withing device and the research-established device worn on the wrist (GENEActiv) for measuring the number of steps also decreased during the treadmill phases (first stage: r = 0.48, bias = 0.6 steps/min; fourth stage: r = 0.48, bias = 17.3 steps/min). Energy expenditure agreement between the Withings device and the indirect calorimetry method was poor during the treadmill test (|r| ≤ 0.29, |bias | ≥ 1.7 MET). The Tucky thermometer under the armpit (consumer-grade) and the Tcore sensor on the forehead were found to be in poor agreement in measuring (core) body temperature during resting phases (r ≤ 0.53, |bias| ≥ 0.8°C) and deteriorated during the treadmill test.

Conclusion

The Withings device showed adequate performance for heart rate at low activity levels and step count at higher activity levels, but had limited overall accuracy. The Tucky device showed poor agreement with the Tcore in all six different activity phases. The limited accuracy of consumer-grade devices suggests caution in their use for rigorous research, but points to their potential utility in capture general physiological trends in long-term field monitoring or population-health surveillance.

Prospective association of estimated cardiorespiratory fitness and risk of chronic kidney diseases

Previous studies have reported that cardiorespiratory fitness (CRF) was associated with decreased risk of chronic kidney disease (CKD) in westerner. The aim of present study was to investigate the potential association between estimated eCRF (eCRF) and CKD risk in Chinese general population. A total of 5,199 participants from the China Health and Retirement Longitudinal Study were including in analysis. The sex-specific models including age, physical activity, resting heart rate, and waist circumference were used to calculate eCRF. Participants were divided into three subgroups according to age and sex-specific tertiles of eCRF. Cox proportional hazards regression models were used to examine the associations between eCRF and CKD. During 9 years of follow-up, a total of 511 respondents experienced CKD. After adjustment for potential variables, the hazard ratio (95% confidence intervals) for the tertile 2 and tertile 3 of eCRF- WC was 0.80 (0.66-0.96) and 0.74 (0.60-0.92), respectively, compared with the lowest tertiles. Moreover, each 1-SD increase of eCRF- WC was associated with 6% (95%CIs, 1-11%) decreased risk of CKD. Similar associations were also found in both male and female subgroups. When the current study calculated eCRF using body mass index instead of waist circumference, the highest tertiles of eCRF- BMI was significantly associated with decreased risk of CKD in overall and female participants. A higher eCRF was associated with a decreased risk of CKD in general Chinese population. Future well-designed prospective clinical studies are needed to verify our findings and to assess the effect of eCRF interventions in CKD prevention.

Validity of heart rate measurements in wrist-based monitors across skin tones during exercise

PURPOSE

To evaluate the accuracy of a wrist-based heart rate (HR) monitor at different exercise intensities across different skin tones.

METHODS

Using a cross-sectional design, we compared HR measures from the wrist-based photoplethysmography Fitbit Charge 5 to the Polar H10 chest strap at rest and during the YMCA Protocol using a recumbent cycle ergometer. Participant were grouped into three skin tone categories: light (Fitzpatrick Scale Skin Types 1+2), medium (Types 3+4), and darker skin tone (Types 5+6). HR measures using the Polar chest strap during the exercise test were categorized as <40%, 40-60%, or >60% HR reserve (HRR). Absolute error in beats per minute (bpm) between the two devices was calculated for each measure. A linear mixed effects model was used to assess interaction effects between skin tone and exercise intensity, with participants as the random effect. Bland-Altman plots were used for visual analyses.

RESULTS

Twenty-five participants [mean (SD): 25.8 (1.9) years old; 64% female] were included with 495 observations of simultaneous Fitbit and Polar HR recordings collected during exercise. During exercise, we observed a statistically significant interaction effect between skin tone and exercise intensity. Compared with light skin tone at <40% HRR, mean error was greater for medium skin tone at >60% HRR [mean error (95%CI): 11.8 (5.6-17.9) bpm, p<0.001] and darker skin tone at 40-60% HRR [7.6 (1.7-13.5) bpm, p = 0.011] and >60% HRR [11.7 (5.3-18.0) bpm, p<0.001].

CONCLUSION

HR measurement error using a wrist-based device was greater with increasing exercise intensity for people with darker skin tones.

Study on the effect of full body isometric resistance training on cardiovascular pressure response

BACKGROUND AND AIMS

Exploring the effect of different isometric resistance training (IRT) on improving blood pressure, so as to provide important reference for the design of aerobic exercise prescription for IRT to improve blood pressure.

METHODS

Forty eight overweight or obese college students with irregular exercise habits were randomly divided into four groups and underwent exercise intervention three times a week for a total of 6 weeks. Cardiovascular changes were evaluated before the first and 18th exercise sessions, as well as 0, 30, and 60 min after exercise.

RESULTS

Heart rate (HR) of equal distance wall squat group (ISG) and whole body equal length exercise group (WIG) increased significantly immediately after exercise, but long-term IRT intervention significantly decreased systolic blood pressure (SBP), diastolic blood pressure (DBP) and mean arterial pressure (MAP) of WIG and ISG, SBP, and MAP of equal grip strength group (IHG), and DBP and MAP of equal curl up group (ICG); In the first exercise, ICG, ISG, and WIG significantly increased SBP and DBP immediately after exercise, ISG significantly increased MAP immediately after exercise, while in the 18th exercise, IHG, ISG, and WIG significantly increased SBP immediately after exercise, ISG significantly increased DBP and MAP immediately after exercise.

CONCLUSION

IRT is a safe and easy to implement exercise mode. Long-term intervention can effectively control blood pressure, and will not cause excessive cardiovascular pressure response after a single exercise.

Using Free-Living Heart Rate Data as an Objective Method to Assess Physical Activity: A Scoping Review and Recommendations by the INTERLIVE-Network Targeting Consumer Wearables

Wearable technologies open up new avenues for the assessment of individual physical activity behaviour. Particularly, free-living heart rate (HR) data assessed by optical sensors are becoming widely available. However, while an abundancy of scientific information and guidance exists for the processing of raw acceleration data, no universal recommendations for the utilization of continuous HR recordings during free-living conditions are available. Towards Intelligent Health and Well-Being: Network of Physical Activity Assessment (INTERLIVE®) is a joint European initiative of six universities and one industrial partner. The consortium was founded in 2019 and strives towards developing best-practice recommendations in the context of consumer wearables and smartphones. The aim of this scoping review (following PRISMA-ScR procedures) and recommendations was to provide best-practice protocols for deriving individual physical activity profiles from continuous HR recordings by wearables. The recommendations were developed through an initial scoping review, grey literature searches of promotional material and user manuals of leading wearable manufacturers as well as evidence-informed discussions among the members of the INTERLIVE®-network. The scoping review was performed on the generic domains required for physical activity assessment, namely: (1) 'assessment of maximal heart rate', (2) 'determination of basal and/or resting heart rate' and (3) 'heart rate-derived intensity zones', for which we finally included a total of 72, 2 and 11 eligible papers, respectively. Gathering recent knowledge, we provide a decision tree and detailed recommendations for the analysis of free-living HR data to derive individual physical activity profiles. Moreover, we also provide examples of HR-metric calculations that help to illustrate data processing and reporting.

Comprehensive cardiac rehabilitation utilized to support patients with heart failure for balancing treatment and work: A case report

A 47-year-old woman with exertional dyspnea was admitted to our hospital. Echocardiography revealed congestive heart failure (HF), with reduced left ventricular ejection fraction (13 %) and elevated brain natriuretic peptide levels (877 pg/mL). The patient underwent medical therapy and comprehensive cardiac rehabilitation (CR). At discharge, the oxygen uptake at anaerobic threshold (AT) was 13.1 mL/kg/min. Outpatient CR consisted of exercise therapy, patient education, and home activity intensity instructions with pulse rate (PR) management using a wearable device. We instructed that activity intensity at home should not exceed the PR at AT. Two months after discharge, the patient's condition was stable, and she was compliant with activity intensity restrictions; therefore, she was allowed to return to work twice a week for 5 h of light work weekly, which was gradually increased. We continued to monitor the PR with wearable devices to ensure compliance with work intensity. Five months after discharge, she achieved a return to work four times a week for 8 h without exacerbation of HF symptoms. The workplace was receptive to the suggestions of the CR team regarding workplace conditions, safe working hours, and frequency, and the patient successfully returned to work, achieving a balance between treatment and work.

Learning objective

The use of comprehensive cardiac rehabilitation is recommended for the return to work by patients with heart failure. However, specific measures to manage activity intensity for return to work have not been considered fully. The strategy that we adopted involved a combination of comprehensive cardiac rehabilitation and the use of wearable devices for guided work intensity management, allowing for a balance between treatment and work responsibilities.