Trainability for cardiopulmonary fitness is low in patients with peripheral artery disease

AIMS

In patients with peripheral arterial disease (PAD), exercise therapy is recommended to relieve leg symptoms, as noted in the 2016 AHA/ACC and 2017 ESC/ESVS guidelines. We assessed the trainability for cardiopulmonary fitness (CPF) and quality of life (QOL); three distinct patient types, namely, PAD, heart failure (HF), and stroke, were compared.

METHODS AND RESULTS

This is a multicentre, retrospective analysis of prospectively collected data from three clinical studies. Data collected from 123 patients who completed 36 sessions of supervised aerobic training of moderate intensity were analysed, with 28 PAD, 55 HF, and 40 stroke patients totalling 123. Before and after training, cardiopulmonary exercise testing with non-invasive cardiac output monitoring and QOL evaluation using a 36-Item Short Form Survey (SF-36) were performed. Non-response was defined as a negative change in the post-training value compared with that in the pre-training value. The result showed an improvement in CPF in all three groups. However, cardiorespiratory fitness (CRF) increased by a lesser extent in the PAD group than in the HF and stroke groups; the physical and mental component scores (MCS) of SF-36 exhibited a similar pattern. Non-response rates of peak V˙O2, oxygen uptake efficiency slope, and MCS were higher in the PAD group. In the PAD group, non-responders regarding peak V˙O2 had a higher pulse wave velocity than responders.

CONCLUSION

In patients with PAD following exercise therapy, CRF and QOL improved to a lesser extent on average; their non-response rate was also higher compared with that of HF or stroke patients. Therefore, a higher dose of exercise might be needed to elicit adaptation in PAD patients, especially those with high pulse wave velocity.

Long-term heat acclimation training in mice: Similar metabolic and running performance adaptations despite a lower absolute intensity than training at temperate conditions

This study investigated the impact of long-term heat acclimation (HA) training on mouse thermoregulation, metabolism, and running performance in temperate (T) and hot (H) environments. Male Swiss mice were divided into 1) Sedentary (SED) mice kept in T (22 °C; SED/T), 2) Endurance Trained mice (ET, 1 h/day, 5 days/week, 8 weeks, 60 % of maximum speed) in T (ET/T), 3) SED kept in H (32 °C; SED/H), and 4) ET in H (ET/H). All groups performed incremental load tests (ILT) in both environments before (pre-ET) and after four and eight weeks of ET. In the pre-ET period, H impaired (∼30 %) performance variables (maximum speed and external work) and increased (1.3 °C) maximum abdominal body temperature compared with T. In T, after four weeks, although ET/H exercised at a lower (∼30 %) absolute intensity than ET/T, performance variables and aerobic power (peak oxygen uptake, VO2peak) were similarly increased in both ET groups compared with SED/T. After eight weeks, the external work was higher in both ET groups compared with SED/T. Only ET/T significantly increased VO2peak (∼11 %) relative to its pre-ET period. In H, only after eight weeks, both ET groups improved (∼19 %) maximum speed and reduced (∼46 %) post-ILT blood lactate concentrations compared with their respective pre-ET values. Liver glycogen content increased (34 %) in both ET groups and SED/H compared with SED/T. Thus, ET/H was performed at a lower absolute intensity but promoted similar effects to ET/T on metabolism, aerobic power, and running performance. Our findings open perspectives for applying HA training as part of a training program or orthopedic and metabolic rehabilitation programs in injured or even obese animals, reducing mechanical load with equivalent or higher physiological demand.

The inorganic NItrate and eXercise performance in Heart Failure (iNIX-HF) phase II clinical trial: Rationale and study design

Background

Heart failure (HF) is a debilitating and often fatal disease that affects millions of people worldwide. Diminished nitric oxide synthesis, signaling, and bioavailability are believed to contribute to poor skeletal muscle function and aerobic capacity. The aim of this clinical trial (iNIX-HF) is to determine the acute and longer-term effectiveness of inorganic nitrate supplementation on exercise performance in patients with HF with reduced ejection fraction (HFrEF).

Methods

This clinical trial is a double-blind, placebo-controlled, randomized, parallel-arm design study in which patients with HFrEF (n = 75) are randomized to receive 10 mmol potassium nitrate (KNO3) or a placebo capsule daily for 6 wk. Primary outcome measures are muscle power determined by isokinetic dynamometry and peak aerobic capacity (VO2peak) determined during an incremental treadmill exercise test. Endpoints include the acute effects of a single dose of KNO3 and longer-term effects of 6 wk of KNO3. The study is adequately powered to detect expected increases in these outcomes at P < 0.05 with 1-β>0.80.

Discussion

The iNIX-HF phase II clinical trial will evaluate the effectiveness of inorganic nitrate supplements as a new treatment to ameliorate poor exercise capacity in HFrEF. This study also will provide critical preliminary data for a future 'pivotal', phase III, multi-center trial of the effectiveness of nitrate supplements not only for improving exercise performance, but also for improving symptoms and decreasing other major cardiovascular endpoints. The potential public health impact of identifying a new, relatively inexpensive, safe, and effective treatment that improves overall exercise performance in patients with HFrEF is significant.

When two Z-scores meet-analysis of exercise capacity of children and adolescents with Kawasaki disease by a new Z-score model of coronary artery and a new Z-score evaluating peak oxygen consumption : Coronary artery Z-score and peakVO2 Z-score in KD

BACKGROUND

Coronary artery (CA) Z-score system is widely used to define CA aneurysm (CAA). Children and adolescents after acute stage of Kawasaki disease (KD-CA) have a higher risk of developing CAAs if their CA Z-score ≥ 2.5. Z-score system of peak oxygen consumption (Peak VO2 Z-score) allows comparisons across ages and sex, regardless of body size and puberty. We aimed to compare the exercise capacity (EC) indicated by peak VO2 Z-score during cardiopulmonary exercise testing (CPET) directly between KD-CA with different CA Z-score.

METHODS

KD-CA after acute stage who received CPET in the last 5 years were retrospectively recruited. CA Z-score was based on Lambda-Mu-Sigma method. Max-Z was the maximum CA Z-score of different CAs. KD children with Max-Z < 2.5 and ≥ 2.5 were defined as KD-1 and KD-2 groups, respectively. Peak VO2 Z-score was calculated using the equation established based on Hong Kong Chinese children and adolescent database.

RESULTS

One hundred two KD-CA were recruited (mean age: 11.71 ± 2.57 years). The mean percent of measured peak VO2 to predicted value (peak PD%) was 90.11 ± 13.33. All basic characteristics and baseline pulmonary function indices were comparable between KD-1 (n = 87) and KD-2 (n = 15). KD-1 had significantly higher peak VO2 Z-score (p = .025), peak PD% (p = .008), peak metabolic equivalent (p = .027), and peak rate pressure product (p = .036) than KD-2.

CONCLUSIONS

KD-CA had slightly reduced EC than healthy peers. KD-CA with Max-Z ≥ 2.5 had significantly lower peak EC than those < 2.5. Max-Z is potentially useful follow-up indicator after acute stage of KD.

Trajectories of cardiorespiratory fitness from childhood to adolescence: Findings from the QUALITY cohort

Estimate the shape and number of cardiorespiratory fitness (CRF) trajectories from childhood to adolescence; and verify whether CRF trajectory membership can be predicted by sex, biological maturation, body weight, body composition and physical activity (PA) in childhood. Data from QUALITY were used. Participants attended baseline (8-10 y old, n = 630) and follow-ups 2 years (n = 564) and 7 years (n = 359) after baseline. Group-based trajectory analysis for relative peak oxygen consumption (VO2peak, ml·kg-1·min-1) was performed. A multinomial logistic regression model was used to estimate the associations between baseline predictors and trajectory membership. Mean age of the 454 participants was 9.7 ± 0.9 years at baseline. Three distinct VO2peak trajectories were identified and all tended to decrease. They were labelled according to the starting point and slope. High-Decreasers were mostly boys, had lower body weight and fat-free mass index and higher PA levels at baseline (p < 0.05). Female sex and higher weight were associated with higher odds of being classified in the Low-Decreaser trajectory (OR = 74.03, 95%CI = 27.06-202.54; OR = 1.48, 95%CI = 1.36-1.60). Those with higher PA were less likely to be Low-Decreasers (OR = 0.96, 95%CI = 0.94-0.97). Sex, body weight and PA in childhood are important influencing factors of VO2peak (ml·kg-1·min-1) trajectories across adolescence.

Physical capacity increase in patients with heart failure is associated with improvement in muscle sympathetic nerve activity

BACKGROUND

Exercise training improves physical capacity in patients with heart failure with reduced ejection fraction (HFrEF), but the mechanisms involved in this response is not fully understood. The aim of this study was to determine if physical capacity increase in patients HFrEF is associated with muscle sympathetic nerve activity (MSNA) reduction and muscle blood flow (MBF) increase.

METHODS

The study included 124 patients from a 17-year database, divided according to exercise training status: 1) exercise-trained (ET, n = 83) and 2) untrained (UNT, n = 41). MSNA and MBF were obtained using microneurography and venous occlusion plethysmography, respectively. Physical capacity was evaluated by cardiopulmonary exercise test. Moderate aerobic exercise was performed 3 times/wk. for 4 months.

RESULTS

Exercise training increased peak oxygen consumption (V̇O2, 16.1 ± 0.4 vs 18.9 ± 0.5 mL·kg-1·min-1, P < 0.001), LVEF (28 ± 1 vs 30 ± 1%, P = 0.027), MBF (1.57 ± 0.06 vs 2.05 ± 0.09 mL.min-1.100 ml-1, P < 0.001) and muscle vascular conductance (MVC, 1.82 ± 0.07 vs 2.45 ± 0.11 units, P < 0.001). Exercise training significantly decreased MSNA (45 ± 1 vs 32 ± 1 bursts/min, P < 0.001). The logistic regression analyses showed that MSNA [(OR) 0.921, 95% CI 0.883-0.962, P < 0.001] was independently associated with peak V̇O2.

CONCLUSIONS

The increase in physical capacity provoked by aerobic exercise in patients with HFrEF is associated with the improvement in MSNA.

Total Hemoglobin Mass Correlates with Peak Oxygen Consumption in Patients with Chronic Stroke

BACKGROUND

The peak oxygen consumption (V.O2peak) and blood hemoglobin concentration [Hb] are lower in stroke patients than in age-matched healthy subjects. The ability of skeletal muscles to extract oxygen is diminished after stroke. We hypothesized that the oxygen extraction capacity of skeletal muscles in stroke patients depends on [Hb]. To test the hypothesis, we determined the relationship between V.O2peak and total hemoglobin mass (tHb-mass) in stroke patients.

METHODS

The subjects were 19 stroke patients (age: 74 ± 2, mean ± SD, 10 males) and 11 age-matched normal subjects (age 76 ± 3, 6 males). Plasma volume (PV) and V.O2peak were measured on the same day. PV was measured using Evans Blue dye dilution method. Blood volume (BV) was calculated from PV and hematocrit, while tHb-mass was estimated from BV and [Hb]. Each subject underwent cardiopulmonary exercise test on a bicycle ergometer using a V.O2peak respiratory gas analyzer.

RESULTS

There were no differences in age, height, and weight between the two groups. V.O2peak was lower in stroke patients than in the control. BV and tHb mass were not significantly different between the two groups, but [Hb] was significantly lower in stroke patients. In stroke patients, V.O2peak correlated significantly with tHb-mass (r = 0.497, p < 0.05), but not with BV.

CONCLUSION

Our results suggested that low [Hb] seems to contribute to V.O2peak in stroke patients. The significant correlation between tHb-mass and V.O2peak suggested that treatment to improve [Hb] can potentially improve V.O2peak in stroke patients.

Evaluation of long-term sequelae by cardiopulmonary exercise testing 12 months after hospitalization for severe COVID-19

BACKGROUND

Cardiopulmonary exercise testing (CPET) is an important clinical tool that provides a global assessment of the respiratory, circulatory and metabolic responses to exercise which are not adequately reflected through the measurement of individual organ system function at rest. In the context of critical COVID-19, CPET is an ideal approach for assessing long term sequelae.

METHODS

In this prospective single-center study, we performed CPET 12 months after symptom onset in 60 patients that had required intensive care unit treatment for a severe COVID-19 infection. Lung function at rest and chest computed tomography (CT) scan were also performed.

RESULTS

Twelve months after severe COVID-19 pneumonia, dyspnea was the most frequently reported symptom although only a minority of patients had impaired respiratory function at rest. Mild ground-glass opacities, reticulations and bronchiectasis were the most common CT scan abnormalities. The majority of the patients (80%) had a peak O₂ uptake (V'O₂) considered within normal limits (median peak predicted O₂ uptake (V'O₂) of 98% [87.2-106.3]). Length of ICU stay remained an independent predictor of V'O₂. More than half of the patients with a normal peak predicted V'O₂ showed ventilatory inefficiency during exercise with an abnormal increase of physiological dead space ventilation (VD/Vt) (median VD/VT of 0.27 [0.21-0.32] at anaerobic threshold (AT) and 0.29 [0.25-0.34] at peak) and a widened median peak alveolar-arterial gradient for O₂ (35.2 mmHg [31.2-44.8]. Peak PetCO₂ was significantly lower in subjects with an abnormal increase of VD/Vt (p = 0.001). Impairments were more pronounced in patients with dyspnea. Peak VD/Vt values were positively correlated with peak D-Dimer plasma concentrations from blood samples collected during ICU stay (r² = 0.12; p = 0.02) and to predicted diffusion capacity of the lung for carbon monoxide (D_LCO) (r² =  - 0.15; p = 0.01).

CONCLUSIONS

Twelve months after severe COVID-19 pneumonia, most of the patients had a peak V'O₂ considered within normal limits but showed ventilatory inefficiency during exercise with increased dead space ventilation that was more pronounced in patients with persistent dyspnea.

TRIAL REGISTRATION

NCT04519320 (19/08/2020).

A 2-day cardiopulmonary exercise test in chronic fatigue syndrome patients who were exposed to humidifier disinfectants

Some survivors of humidifier disinfectants (HDs) complain of chronic, inexplicable fatigue, and post-exertional malaise (PEM). Two-day cardiopulmonary exercise tests (CPETs) performed 24 hours apart (2-day CPET protocol) are increasingly employed to evaluate PEM and related disabilities among individuals with chronic fatigue syndrome (CFS). The purpose of this study was to assess the reproducibility of CPET variables in individuals who had been exposed to HD and to show that 2-day CPET is an objective means of differentiating between fatigue conditions in people with CFS symptoms who have been exposed to HDs. Twenty-nine HD survivors with CFS symptoms were enrolled in this study. To document and assess PEM in CFS, a 2-day CPET was conducted to measure baseline functional capacity (CPET1) and provoke PEM. Twenty-four hours later, a second CPET assessed changes in related variables, focusing on PEM effects on functional capacity. This CPET also measured changes in energy production and physiological function, objectively documenting PEM effects. In the 2-day CPET, the peak oxygen consumption (VO2peak), VO2 at ventilatory threshold (VO2@VT), time to reach VO2peak, and time to reach VO2@VT were significantly decreased (p<0.001). The peak O2 pulse and O2 pulse at VT also decreased significantly (p<0.001). A 6-minute walk test revealed significantly decreased distance (p<0.01). This is the first study to conduct a 2-day consecutive CPET in previously exposed HD participants with CFS symptoms. Our results confirm previous work that demonstrated abnormal responses to PEM in CFS patients. Therefore, a 2-day CPET is an objective measure to differentiate fatigue conditions in people with CFS symptoms who have been exposed to HDs.

Peak oxygen uptake is a strong prognostic predictor for pulmonary hypertension due to left heart disease

Background

Pulmonary hypertension in left heart disease (PH-LHD), which includes combined post- and precapillary PH (Cpc-PH) and isolated postcapillary PH (Ipc-PH), differs significantly in prognosis. We aimed to assess whether cardiopulmonary exercise testing (CPET) predicts the long-term survival of patients with PH-LHD.

Methods

A single-center observational cohort enrolled 89 patients with PH-LHD who had undergone right heart catherization and CPET (mean pulmonary arterial pressure > 20 mm Hg and pulmonary artery wedge pressure ≥ 15 mm Hg) between 2013 and 2021. A receiver operating characteristic curve was plotted to determine the cutoff value of all-cause death. Survival was estimated using the Kaplan–Meier method and analyzed using the log-rank test. The Cox proportional hazards model was performed to determine the association between CPET and all-cause death.

Results

Seventeen patients died within a mean of 2.2 ± 1.3 years. Compared with survivors, nonsurvivors displayed a significantly worse 6-min walk distance, workload, exercise time and peak oxygen consumption (VO₂)/kg with a trend of a lower oxygen uptake efficiency slope (OUES) adjusted by Bonferroni’s correction. Multivariate Cox regression revealed that the peak VO₂/kg was significantly associated with all-cause death after adjusting for Cpc-PH/Ipc-PH. Compared with Cpc-PH patients with a peak VO₂/kg ≥ 10.7 ml kg⁻¹ min⁻¹, Ipc-PH patients with a peak VO₂/kg < 10.7 ml kg⁻¹ min⁻¹ had a worse survival (P < 0.001).

Conclusions

The peak VO₂/kg is independently associated with all-cause death in patients with PH-LHD. The peak VO₂/kg can also be analyzed together with Cpc-PH/Ipc-PH to better indicate the prognosis of patients with PH-LHD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12872-022-02574-0.

Short-term High-Intensity Interval Training Improves Fitness Before Surgery: A Randomised Clinical Trial

PURPOSE

Improving cardiopulmonary reserve, or peak oxygen consumption( V ˙ O_2peak ), may reduce postoperative complications, however this may be difficult to achieve between diagnosis and surgery. Our primary aim was to assess the efficacy of an approximate 14-session, preoperative High Intensity Interval Training(HIIT) program to increase V ˙ O_2peak by a clinically-relevant 2 mL·kg^-1 ·min^-1 . Our secondary aim was to document clinical outcomes.

METHODOLOGY

In this prospective study, participants aged 45-85 undergoing major abdominal surgery were randomised to standard care or 14 sessions of HIIT over 4 weeks. HIIT sessions involved approximately thirty minutes of stationary cycling. Interval training alternated one minute of high (with the goal of reaching 90% max heart rate at least once during the session) and low/moderate intensity cycling. Cardiopulmonary exercise testing(CPET) measured the change in V ˙ O_2peak from baseline to surgery. Clinical outcomes included postoperative complications, length of stay(LOS) and Short Form-36 quality of life questionnaire(SF-36).

RESULTS

Of 63 participants, 46 completed both CPETs and 50 completed clinical follow-up. There was a significant improvement in the HIIT group's mean ± SD V ˙ O_2peak (HIIT 2.87 ± 1.94 mL·kg¹ ·min^-1 vs standard care 0.15 ± 1.93, with an overall difference of 2.73 mL·kg¹ ·min^-1 95%CI [1.53, 3.93] p<0.001). There were no statistically significant differences between groups for clinical outcomes, although the observed differences consistently favoured the exercise group. This was most notable for total number of complications (0.64 v 1.16 per patient, p=0.07), SF-36 physical component score (p=0.06), and LOS (mean 5.5 v 7.4 days, p=0.07).

CONCLUSIONS

There was a significant improvement in V ˙ O_2peak with a four-week preoperative HIIT program. Further appropriately-powered work is required to explore the impact of preoperative HIIT on postoperative clinical outcomes.

Body composition and maximal exercise capacity after heart transplantation

Aims

Maximal exercise capacity as measured by peak oxygen consumption (pVO₂) in cardiopulmonary exercise testing (CPET) of heart transplant recipients (HTR) is limited to a 50–70% level of healthy age‐matched controls. This study investigated the relationship between body composition and pVO₂ during the first decade post‐transplant.

Methods and results

Body composition was determined by dual‐energy X‐ray absorptiometry (DXA) and pVO₂ by CPET in 48 HTR (n = 38 males; mean age 51 ± 12 years). A total of 95 assessments were acquired 1–9 years post‐transplant, and the results of four consecutive periods were compared [Period 1: 1–2 years (n = 25); 2: 3–4 years (n = 23); 3: 5–6 years (n = 23); 4: 7–9 years (n = 24)]. Linear regression analysis analysed the correlation between pVO₂ and pairs of appendicular lean mass (ALM) and fat mass (FM). The relation between ALM and daily dose of calcineurin inhibitor (CNI) was explored using partial correlation controlling for age, gender, and height. pVO₂ increased from 0.98 (0.34) to 1.35 (0.35) L/min (P < 0.01) between Periods 1 and 4 corresponding to 54.5–63.3% of predicted value. Peak heart rate (HR) raised from 115 ± 19 to 131 ± 23 b.p.m. (P = 0.05), and anaerobic threshold (AT = VO₂ achieved at AT) increased from 0.57 (0.18) to 0.83 (0.35) L/min (P < 0.01) between Periods 1 and 3. Median FM normalized to height² (FMI) always remained elevated (>8.8 kg/m²). ALM normalized to body mass index increased from 0.690 (0.188) to 0.848 (0.204) m² (P = 0.02) between Periods 1 and 4, explaining 45% of the variance of pVO₂ (R² = 0.455; P < 0.001). Eighty‐one per cent of the variance of pVO₂ (R² = 0.817; P < 0.001) in multiple regression was explained by AT (β = 0.488), ALM (β = 0.396), peak HR (β = 0.366), and FMI (β = −0.181). ALM was negatively correlated with daily CNI dose (partial R = −0.258; P = 0.01).

Conclusions

After heart transplantation, the beneficial effect of peripheral skeletal muscle gain on pVO₂ is opposed by increased FM. Our findings support lifestyle efforts to fight adiposity and CNI dose reduction in the chronic stable phase to favour positive adaptation of peripheral muscle mass.

Association of device-measured physical activity with peak oxygen consumption measured by cardiopulmonary exercise testing in patients with cardiac implantable electronic devices

PURPOSE

Cardiac implantable electronic devices (CIEDs) offer diagnostic information such as device-measured physical activity (PA). Peak oxygen consumption (VO₂) measured by cardiopulmonary exercise testing (CPET) is the most objective variable showing exercise capacity. The purpose of this study was to investigate the relationship between these 2 variables.

METHODS

We retrospectively studied consecutive patients with CIEDs undergoing CPET between April 1, 2018, and January 31, 2021. These patients were divided into 2 groups: patients with peak VO₂ ≤ 14 ml/kg/min (low peak VO₂ group) and those showing peak VO₂ > 14 ml/kg/min (high peak VO₂ group). The peak device-measured PA was compared between the 2 groups. The relationship between the peak device-measured PA and peak VO₂ was also investigated.

RESULTS

There were 50 and 51 patients in the low and high peak VO₂ groups, respectively. The peak device-measured PA, which was expressed in units of hours/day, was significantly lower in the low peak VO₂ group than in the high peak VO₂ group (3.06, interquartile range [2.43-4.00] vs. 5.50, interquartile range [4.04-6.70] p < 0.01). The peak device-measured PA and peak VO₂ showed a significant positive correlation (Spearman's ρ = 0.53; p < 0.01). Furthermore, receiver operating characteristic curve analysis showed that a peak device-measured PA > 3.87 h/day could predict high peak VO₂ (80.4%, sensitivity; 72.0%, specificity). In multivariate linear regression analysis, peak device-measured PA was an independent predictor of peak VO₂ (regression coefficient, 0.61; 95% confidence interval, 0.33-0.89; p < 0.01).

CONCLUSIONS

Peak device-measured PA was significantly associated with peak VO₂.

Scaling the peak and steady-state aerobic power of running and walking humans

PURPOSE

The first aim of this experiment was to evaluate the appropriateness of linear and non-linear (allometric) models to scale peak aerobic power (oxygen consumption) against body mass. The possibilities that oxygen consumption would scale allometrically across the complete metabolic range, and that the scaling exponents would differ significantly between basal and maximal-exercise states, were then evaluated. It was further hypothesised that the scaling exponent would increase in a stepwise manner with elevations in exercise intensity. Finally, the utility of applying the scaling exponent derived for peak aerobic power to another population sample was evaluated.

METHODS

Basal, steady-state walking and peak (treadmill) oxygen-consumption data were measured using 60 relatively homogeneous men (18-40 year; 56.0-117.1 kg), recruited across five mass classes. Linear and allometric regressions were applied, with the utility of each scaling method evaluated.

RESULTS

Oxygen consumption scaled allometrically with body mass across the complete metabolic range, and was always superior to both ratiometric analysis and linear regression. The scaling exponent increased significantly from rest (mass^0.57) to maximal exercise (mass^0.75; P < 0.05), but not between steady-state walking (mass^0.87) and maximal exercise (P > 0.05). When used with an historical database, the maximal-exercise exponent successfully removed the mass bias.

CONCLUSION

It has been demonstrated that the oxygen consumption of healthy humans scales allometrically with body mass across the entire metabolic range. Moreover, only two scaling exponents (rest and exercise) were required to produce mass-independent outcomes from those data. Accordingly, ratiometric and linear regression analyses are not recommended as scaling methods.

Deconditioning does not explain orthostatic intolerance in ME/CFS (myalgic encephalomyelitis/chronic fatigue syndrome)

BACKGROUND

Orthostatic intolerance (OI) is a frequent finding in individuals with myalgic encephalomyelitis /chronic fatigue syndrome (ME/CFS). Published studies have proposed that deconditioning is an important pathophysiological mechanism in various forms of OI, including postural orthostatic tachycardia syndrome (POTS), however conflicting opinions exist. Deconditioning can be classified objectively using the predicted peak oxygen consumption (VO₂) values from cardiopulmonary exercise testing (CPET). Therefore, if deconditioning is an important contributor to OI symptomatology, one would expect a relation between the degree of reduction in peak VO₂during CPET and the degree of reduction in CBF during head-up tilt testing (HUT).

METHODS AND RESULTS

In 22 healthy controls and 199 ME/CFS patients were included. Deconditioning was classified by the CPET response as follows: %peak VO₂ ≥ 85% = no deconditioning, %peak VO₂ 65-85% = mild deconditioning, and %peak VO₂ < 65% = severe deconditioning. HC had higher oxygen consumption at the ventilatory threshold and at peak exercise as compared to ME/CFS patients (p ranging between 0.001 and < 0.0001). Although ME/CFS patients had significantly greater CBF reduction than HC (p < 0.0001), there were no differences in CBF reduction among ME/CFS patients with no, mild, or severe deconditioning. We classified the hemodynamic response to HUT into three categories: those with a normal heart rate and blood pressure response, postural orthostatic tachycardia syndrome, or orthostatic hypotension. No difference in the degree of CBF reduction was shown in those three groups.

CONCLUSION

This study shows that in ME/CFS patients orthostatic intolerance is not caused by deconditioning as defined on cardiopulmonary exercise testing. An abnormal high decline in cerebral blood flow during orthostatic stress was present in all ME/CFS patients regardless of their %peak VO₂ results on cardiopulmonary exercise testing.

Does Premature Ventricular Contractions Affect Exercise Capacity in Teenagers with Normal Hearts?

Premature ventricular contractions (PVCs) are common in teenagers even in the absence of structural heart disease or channelopathy. The suppression of PVCs with exercise is a favorable prognostic indicator. There is a paucity of data regarding the relationship between exercise capacity and PVC burden in this population. Our objective was to evaluate the association between various exercise stress parameters and PVC burden ascertained with a 24 h Holter in children without structural heart disease and/or channelopathy. In this retrospective study, 447 patient's charts with a diagnosis of PVC were reviewed at a single tertiary center. The study cohort consisted of ninety one patients with no structural heart disease or channelopathy who underwent an echocardiogram, maximal stress test, and 24 h Holter monitor. The cohort was divided into two groups based on PVC burden by 24-h Holter monitoring: < 10% and ≥ 10%. Peak oxygen uptake (VO₂ in ml/kg/min), an indicator of maximal aerobic capacity, was collected. Other exercise parameters included a) percentage of predicted VO₂ (%VO₂) based on age, weight, height, and gender b) percent oxygen pulse, c) Anaerobic threshold (AT), and d) Metabolic equivalents. Demographic and exercise stress test-derived parameters were compared between the two groups using student t test and a p value < 0.05 was considered significant. In our cohort of 91 patients, the mean (SD) age at exercise was 14.5 (3.2) years with 56 (62%) males. Left ventricle shortening fraction (LVFS) was ≥ 28% in all enrolled patients. PVCs were monomorphic in 72(80%) patients. The mean (SD) PVC burden was 14.43% (12.3) ranging from 0.1 to 49.8%. PVC burden was ≥ 10% in 48 (53%) patients. Eighty eight (97%) patients in the study cohort had suppression of PVCs with exercise. There were no significant differences between the two groups (< 10% vs. ≥ 10% PVC burden) with respect to demographic or exercise test-derived parameters. Univariate regression between PVC burden and %VO₂ did not show significant correlation (r = - 0.04, p = 0.75). Children even with ≥ 10% PVC burden did not demonstrate any objective decrease in their exercise capacity. A plausible reason for no difference in exercise capacity in our cohort may be due to lower PVC load or shorter duration of PVCs compared to adults.

Prognostic value of cardiopulmonary exercise testing in cardiac amyloidosis

AIMS

In amyloid patients, cardiac involvement dramatically worsens functional capacity and prognosis. We sought to study how the cardiopulmonary exercise test (CPET) could help in functional assessment and risk stratification of patients with cardiac amyloidosis (CA).

METHODS AND RESULTS

We carried out a multicentre study including patients with light chain (AL) or transthyretin (TTR) CA. All patients underwent exhaustive examination including CPET and follow-up. The primary prognostic endpoint was the occurrence of death or heart failure hospitalization. Overall, 150 patients were included (91 AL and 59 TTR CA). Median age, systolic blood pressure, N-terminal pro B-type natriuretic peptide (NT-proBNP) and cardiac troponin T were 70 (64-78) years, 121 [interquartile range (IQR) 109-139] mmHg, 2806 (IQR 1218-4638) ng/L and 64 (IQR 33-120) ng/L, respectively. New York Heart Association classes were I-II in 64%. Median peak oxygen consumption (VO₂ ) and circulatory power were low at 13.0 (10.0-16.9) mL/kg/min and 1730 (1318-2614) mmHg/mL/min, respectively. The minute ventilation/carbon dioxide production slope was increased to 37 (IQR 33-45). A total of 77 patients (51%) had chronotropic insufficiency. After a median follow-up of 20 months, there were 37 deaths and 44 heart failure hospitalizations. At multivariate Cox analysis, peak VO₂  ≤13 mL/kg/min [hazard ratio (HR) 2.7, 95% confidence interval (CI) 1.6-4.8], circulatory power ≤1730 mmHg/mL/min (HR 2.4, 95% CI 1.2-4.6) and NT-proBNP ≥1800 ng/L (HR 2.2, 95% CI 1.1-4.3) were found to be associated with the primary outcome. No events occurred in patients with both peak VO₂  >13 mL/kg/min and NT-proBNP <1800 ng/L, while the association of VO₂  ≤13 mL/kg/min with NT-proBNP ≥1800 ng/L identified a very high-risk subgroup.

CONCLUSION

In CA, CPET is helpful in assessing functional capacity, circulatory and chronotropic responses as well as the prognosis of patients along with cardiac biomarkers.

A comprehensive individual patient data meta-analysis of the effects of cardiac contractility modulation on functional capacity and heart failure-related quality of life

Aims

Cardiac contractility modulation, also referred to as CCM™, has emerged as a promising device treatment for heart failure (HF) in patients not indicated for cardiac resynchronization therapy. We performed a comprehensive individual patient data meta‐analysis of all non‐confounded prospective randomized controlled trials of CCM vs. control that have measured functional capacity and/or quality of life questionnaires in patients with HF.

Methods and results

The Cochrane Central Register of Controlled Trials, MEDLINE, and EMBASE were searched in January 2020 to identify eligible randomized controlled trials. We also asked the sole manufacturer of the device for their list of known trials. Primary outcomes of interest were peak oxygen consumption (peak VO₂), 6 min walk test distance, and quality of life measured by Minnesota Living with Heart Failure Questionnaire (MLWHFQ), and all data were received as individual patient and individual time point data‐points. Mean differences and 95% confidence intervals (CIs) were calculated for continuous data using a fixed‐effects model. Five trials were identified, four randomized studies enrolling 801 participants for all endpoints of interest, and for peak VO₂ alone (n = 60), there was an additional single arm non‐randomized trial (FIX‐HF‐5C2) with a prospective comparison of its 24 week peak VO₂ data compared with the control group of the FIX‐HF‐5C control patients. Pooled analysis showed that, compared with control, CCM significantly improved peak VO₂ (mean difference +0.93, 95% CI 0.56 to 1.30 mL/kg/min, P < 0.00001), 6 min walk test distance (mean difference +17.97, 95% CI 5.48 to 30.46 m, P = 0.005), and quality of life measured by MLWHFQ (mean difference −7.85, 95% CI −10.76 to −4.94, P < 0.00001). As a sensitivity analysis, we excluded the FIX‐HF‐5C2 trial (only relevant for peak VO₂), and the result was similar, mean difference +0.65, 95% CI 0.21 to 1.08 mL/kg/min, P = 0.004.

Conclusions

This comprehensive meta‐analysis of individual patient data from all known randomized trials has shown that CCM provides statistically significant and clinically meaningful benefits in measures of functional capacity and HF‐related quality of life.

Effect of high-intensity interval training in young heart transplant recipients: results from two randomized controlled trials

Background

Little is known about the effect of exercise in young heart transplant recipients, and results on group level is lacking. This study summarizes the findings of the youngest participants in two previous randomized controlled trials.

Method

This is a hypothesis-generating study reporting the main results from the youngest participants in two larger randomized controlled trials investigating the effect of high-intensity interval training (HIT). The article summarizes the main results from 28 young participants (< 40 year of age) who have participated in two previous studies which evaluated the effect of HIT vs. controls in adult heart transplant recipients. One of the studies included de novo heart transplant recipients and the other included maintenance heart transplant recipients.All study tests were performed in-hospital, in the specialist health care setting, but the exercise intervention was carried out locally, in cooperation with the primary health care. In both studies the exercise intervention lasted for 9-12 months. In one study, HIT (85-95% of peak effort) was compared to controls (no specific intervention), and in the other study HIT was compared to moderate, continuous exercise (MICT, 60-80% of peak effort). The main outcome measure was peak oxygen uptake (VO_2peak) and a secondary endpoint was muscle strength.

Results

The summarized findings from the youngest heart transplant recipients in these two studies demonstrated mainly that the improvement in peak oxygen uptake among the younger recipients (< 40 years) was much larger (4.7 vs. 1.2 ml/kg/min and 7.0 vs. 2.2 ml/kg/min) compared to the improvement among the older recipients (≥ 40 years), and in accordance with results from adult heart transplant populations: HIT, compared to MICT, induced the largest improvement in peak oxygen consumption, also in the younger heart transplant recipients.

Conclusions

These results suggest that young heart transplant recipients have a greater effect of HIT than of MICT and may also suggest that younger recipients benefit more from high-intensity interval training than their older co-patients. However, larger randomized studies focusing on the young heart transplant population is strongly needed to confirm this hypothesis.

Trial registration

Clinical trial registrations: NCT01796379 and NCT01091194.

Association of physical activity and cardiorespiratory function or BMI and body composition in preterm-born individuals: a systematic review

AIM

To evaluate the association of physical activity (PA) and forced expiratory volume in one second (FEV1), peak oxygen consumption (pVO2), body mass index (BMI) and body composition in preterm-born individuals.

METHODS

Cochrane Library, EMBASE, MEDLINE, AMED, ERIC, Web of Science and PsycInfo were searched with no restriction on language and date of publication from inception to January 2018. Data were extracted comparing preterm-born individuals with different frequencies of PA and the outcome of interest.

RESULTS

One randomized controlled, two longitudinal and thirteen cross-sectional studies comprising 1922 preterm-born individuals aged 5-25 were included. Assessment varied from a PA program to accelerometer data, interviews and self-report questionnaires. In preterm-born children, more PA was associated with better cardiorespiratory function in those groups with impaired lung function or with lower BMI in those groups with increased risk factors, but no association was found in unimpaired children. In preterm-born adults, more PA was associated with higher pVO2 and lower BMI.

CONCLUSION

Only tentative conclusions can be drawn, especially regarding differences of the association of PA between preterm- and term-born populations. Further studies are needed to analyse the association of PA in preterm-born individuals with reduced cardiorespiratory function.

Two-dimensional speckle tracking echocardiography assessed right ventricular function and exercise capacity in pre-capillary pulmonary hypertension

Resting two-dimensional speckle tracking echocardiography (2D-STE) identified right ventricular (RV) systolic function were reported to predict exercise capacity in pulmonary hypertension (PH) patients, but little attention had been payed to 2D-STE detected RV diastolic function. Therefore, we aim to elucidate and compare the relations between 2D-STE identified RV diastolic/systolic functions and peak oxygen consumption (PVO₂) determined by cardiopulmonary exercise testing (CPET) in pre-capillary PH. 2D-STE was performed in 66 pre-capillary PH patients and 28 healthy controls. Linear correlation and multivariate regression analyses were performed to evaluate and compare the relations between RV 2D-STE parameters and PVO₂. Receiver operating characteristic curves were used to compare the predictive value of 2D-STE parameters in predicting the cut-off-PVO₂ < 11 ml/min/kg. There were significant differences of all the 2D-STE parameters between PH patients and healthy controls. In patients, RV-peak global longitudinal strain (GLS, r_s = - 0.498, P < 0.001), RV- peak systolic strain rate (GSRs, r_s = - 0.537, P < 0.001) and RV- peak early diastolic strain rate (GSRe, r_s = 0.527, P < 0.001) significantly correlated with PVO₂, but no significant correlation was observed between RV- peak late diastolic strain rate (GSRa, r_s = 0.208, P = 0.093) and PVO₂. The first multivariate regression analysis of clinical data without echocardiographic parameters identified WHO functional class, NT-proBNP and BMI as independent predictors of PVO₂ (Model-1, adjusted r² = 0.421, P < 0.001); Then we added conventional echocardiographic parameters and 2D-STE parameters to the clinical data, identified S,(Model-2,adjusted r² = 0.502, P < 0.001), RV-GLS (Model-3, adjusted r² = 0.491, P < 0.001), RV-GSRe (Model-4, adjusted r² = 0.500, P < 0.001) and RV-GSRs (Model-5, adjusted r² = 0.519, P < 0.001) as independent predictors of PVO₂, respectively. The predictive power was increased, and Model-5 including RV-GSRs showed the highest predictive capability. ROC curves found RV-GSRs expressed the strongest predictive value (AUC = 0.88, P < 0.001), and RV-GSRs > - 0.65/s had a 88.2% sensibility and 82.2% specificity to predict PVO₂ < 11 ml/min/kg. 2D-STE assessed RV function improves the prediction of exercise capacity represented by PVO₂ in pre-capillary PH.

Does obstructive sleep apnea affect exercise capacity and the hemodynamic response to exercise? An individual patient data and aggregate meta-analysis

Obstructive sleep apnea (OSA) has been linked to altered cardiovascular response to exercise. A systematic review and individual patient data (IPD) meta-analysis were conducted to assess whether OSA patients present reduced exercise capacity. PubMed, Embase and Web of Science were searched until September 2018. Studies which performed sleep recording in both OSA patients and controls and measured maximal oxygen consumption (VO_2peak) via a maximal exercise test were included. IPD were provided for five trials upon the 18 eligible (N = 289) and a two-stage IPD meta-analysis model was used, allowing to standardize the apnea cutoff and adjust for confounders. IPD meta-analysis demonstrated that moderate to severe OSA patients had similar VO_2peak (mean difference: -1.03 mL·kg^-1 min^-1; 95% CI: -3.82 to 1.76; p = 0.47) and cardiovascular response to exercise compared to mild or non-OSA patients. By contrast, aggregate data (AD) meta-analysis including the 13 trials for which IPD were unavailable (N = 605) revealed that VO_2peak was reduced in OSA patients compared to controls (mean difference: -2.30 mL·kg^-1 min^-1; 95% CI: -3.96 to -0.63; p < 0.001) with high heterogeneity. In conclusion, IPD meta-analysis suggests that VO_2peak and the cardiovascular response to exercise are preserved in moderate to severe OSA patients while AD meta-analysis suggests lower VO_2peak in severe OSA.

Non-alcoholic fatty liver disease: Prevalence and all-cause mortality according to sedentary behaviour and cardiorespiratory fitness. The HUNT Study

PURPOSE

Sedentary behaviour (SB) and low physical activity (PA) are independently associated with non-alcoholic fatty liver disease (NAFLD). Compared to PA, high cardiorespiratory fitness (CRF) has been associated with a higher protection against all-cause mortality and a number of specific diseases. However, this relationship has not been investigated in NAFLD. This study examined the roles of SB and CRF on: i) the likelihood of having NAFLD in the general population, and ii) the risk of mortality over 9 years within individuals having NAFLD.

METHODS

A cross-sectional analysis of 15,781 adults (52% female; age range 19-95 years) was conducted. Self-reported SB was divided into tertiles. CRF was estimated using validated non-exercise models, and the presence of NAFLD from the Fatty Liver Index. Adjusted Odds Ratios and 95% Confidence Intervals for NAFLD were estimated using logistic regression analyses. Hazard Ratios for all-cause mortality were estimated using Cox proportional hazard regression in individuals with NAFLD.

RESULTS

For each additional 1 h/d of SB, the likelihood of having NAFLD was significantly increased by 4% (CI, 3-6%). In combined analyses, compared with the reference group [high CRF and low (≤4 h/d) SB], individuals with low CRF had a markedly higher likelihood of having NAFLD (OR, 16.9; CI 12.9-22.3), even if they had SB ≤ 4 h/d. High CRF attenuated the negative role of SB up to 7 h/d on NAFLD. Over 9.4 ± 1.3 years of follow-up, individuals with NAFLD and low CRF had the risk of mortality increased by 52% (CI, 10-106%) compared to those with high CRF, regardless of SB or meeting PA guidelines.

CONCLUSIONS

Low CRF increases the risk of premature death in individuals with NAFLD, and is strongly associated with higher likelihood of having NAFLD, outweighing the influence of SB.

Association between activity energy expenditure and peak oxygen consumption with sarcopenia

Background

Sedentariness may be an important risk factor for sarcopenia. The aim of this work was to assess the association between muscle mass and strength and markers of usual physical activity such as activity energy expenditure and peak oxygen uptake.

Methods

Young and old participants were assessed measuring body composition by DEXA (double beam X ray absorptiometry), handgrip strength, peak oxygen consumption and workload during an exercise calorimetry in a braked cycle ergometer and a 72 h activity energy expenditure using Actiheart actigraphs. A heart rate/energy expenditure curve derived from the exercise calorimetry was used to calibrate each actigraph. Sarcopenia was defined as having an appendicular fat free mass index below 7.5 kg/m² and 5.6 kg/m² in men and women respectively, or a handgrip strength z score below 1, using local normal data or having both parameters below the cutoff points.

Results

We analyzed data from 192 assessments performed in participants aged 22 to 88 years (106 women). Sarcopenic participants (as determined by muscle mass, strength or both) had a significantly lower peak oxygen uptake and work load and a significantly lower activity energy expenditure. When analyzing lean mass and strength as continuous variables, peak oxygen consumption was a significant predictor of fat free mass in men. Among women, the association was observed only when percentage of muscle mass was expressed as a z score.

Conclusions

Activity energy expenditure and peak oxygen consumption are associated with a lower muscle mass and the presence of sarcopenia and should be considered as risk factors for this condition.

Dietary nitrate's effects on exercise performance in heart failure with reduced ejection fraction (HFrEF)

Heart failure with reduced ejection fraction (HFrEF) is a deadly and disabling disease. A key derangement contributing to impaired exercise performance in HFrEF is decreased nitric oxide (NO) bioavailability. Scientists recently discovered the inorganic nitrate pathway for increasing NO. This has advantages over organic nitrates and NO synthase production of NO. Small studies using beetroot juice as a source of inorganic nitrate demonstrate its power to improve exercise performance in HFrEF. A larger-scale trial is now underway to determine if inorganic nitrate may be a new arrow for physicians' quiver of HFrEF treatments.

Intravenous Iron Therapy in Heart Failure

Iron deficiency anemia is both a comorbid condition and an indicator of poor prognosis in heart failure. The mechanisms by which this occurs are multiple and complex. Recent robust randomized clinical trials have shown significant improvements in quality of life and rates of hospitalization with intravenous repletion of iron. In this article, we review the mechanisms by which iron deficiency impacts heart failure and the evidence behind repletion. There remains a good deal to learn about long-term effects of intravenous iron repletion, and clinical trials are ongoing in this regard.

Exercise Capacity and Self-Efficacy are Associated with Moderate-to-Vigorous Intensity Physical Activity in Children with Congenital Heart Disease

This study sought to determine whether exercise capacity, self-efficacy, and gross motor skills are associated with moderate-to-vigorous physical activity (MVPA) levels in children, and if these associations differ by congenital heart disease (CHD) type. Medical history was abstracted from chart review. We assessed MVPA levels (via accelerometry), percent-predicted peak oxygen consumption ([Formula: see text] cardiopulmonary exercise test), gross motor skill percentiles (test of gross motor development version-2), and self-efficacy [children's self-perceptions of adequacy and predilection for physical activity scale (CSAPPA scale)]. CHD patients (n = 137, range 4-12 years) included children with a repaired atrial septal defect (n = 31, mean ± standard deviation MVPA = 454 ± 246 min/week), transposition of the great arteries after the arterial switch operation (n = 34, MVPA = 423 ± 196 min/week), tetralogy of Fallot after primary repair (n = 37, MVPA = 389 ± 211 min/week), or single ventricle after the Fontan procedure (n = 35, MVPA = 405 ± 256 min/week). MVPA did not differ significantly between CHD groups (p = 0.68). Higher MVPA was associated with a higher percent-predicted [Formula: see text] (EST[95% CI] = 16.9[-0.2, 34] MVPA min/week per 10% increase in percent-predicted [Formula: see text] p = 0.05) and higher self-efficacy (EST[95% CI] = 5.2[1.0, 9.3] MVPA min/week per 1-unit increase in CSAPPA score, p = 0.02), after adjustment for age, sex, and testing seasonality, with no association with CHD type. Higher MVPA was not associated with gross motor skill percentile (p = 0.92). There were no significant interactions between CHD type and percent-predicted [Formula: see text] self-efficacy scores, and gross motor skill percentiles regarding their association with MVPA (p > 0.05 for all). Greater MVPA was associated with higher exercise capacity and self-efficacy, but not gross motor skills.

Comparison of bioenergetics of walking during a multistage incremental shuttle walk test and a 6-min walk test in active older adults

The goal of the present research was to compare the bioenergetics variability of walking, during the 6-min walk test (6-MWT) and a multistage incremental shuttle walk test (MISWT) in an active older population. Twenty-two healthy physically active older adults with a group mean age of 70.4 ± 5.8 years completed the 6-MWT and the MISWT. Heart rate (HR), walking speed and walking [Formula: see text]O₂ were measured throughout each test with a portable metabolic cart. Strong correlations were found for the [Formula: see text]O₂ peak and the walking speed (r = 0.91 and r = 0.89 respectively for 6-MWT and MISWT). Differences in [Formula: see text]O₂ peak values were analysed with a paired Student's t test. Repeated measures ANOVA were conducted to detect differences between tests. The Bland and Altman plot indicates that the average difference between both tests was 2.5 ml kg^-1 min^-1. MISWT [Formula: see text]O₂ peak means were significantly greater than the 6-MWT [Formula: see text]O₂ peak mean values (21.6 ± 5.3 vs. 18.9 ± 4.5 ml kg^-1 min^-1) which indicate bioenergetics differences between the two walking tests. Thus, the MISWT and 6-MWT elicited different walking [Formula: see text]O₂ peak and HR suggesting that the MISWT field test challenge the participants to a higher level of cardiovascular and respiratory stress. The walking [Formula: see text]O₂ peak recorded for the MISWT was significantly greater than the 6-MWT. Consequently, both tests seem to measure different facets of the aerobic capacity. MISWT seems to be a better indicator of maximal aerobic power whereas the 6-MWT provides more relevant information regarding aerobic endurance in aging population.

Cardiovascular Function in Long-Term Hematopoietic Cell Transplantation Survivors

Peak oxygen consumption (VO_2peak), as measured by cardiopulmonary exercise testing (CPET), is a powerful independent predictor of cardiovascular disease (CVD) and all-cause mortality in a broad range of populations. We assessed the safety and feasibility of CPET in aging long-term hematopoietic cell transplantation (HCT) survivors, a population at high risk for premature onset of CVD. Next, we examined how organ-specific impairments (eg, cardiac, pulmonary, hematologic) impact VO_2peak after HCT. Twenty consecutive HCT survivors underwent a comprehensive assessment of cardiopulmonary health that included CPET, echocardiography with strain, pulmonary function testing, 6-minute walk test, and timed up and go. Median age at assessment was 67.4 years (range, 42 to 75), and median time from HCT was 9.8 years (range, 3 to 20). No adverse events were observed during CPET procedures, and 95% of studies were considered to be at "peak" effort (respiratory exchange ratio ≥ 1.10). VO_2peak was on average 22% less than predicted, and allogeneic HCT survivors had markedly lower VO_2peak when compared with autologous HCT survivors (18.2 mL/kg/min versus 22.2 mL/kg/min; P = .05). Six participants (30%) had VO_2peak ≤ 16 mL/kg/min, a threshold associated with a 9-foldrisk of death in patients undergoing HCT. Despite the presence of normal (>50%) resting left ventricular ejection fraction in all participants, 25% had markedly abnormal left ventricular longitudinal strain, an advanced echocardiographic measure of myocardial dysfunction. These findings highlight the role of stress-based measures and advanced myocardial imaging to characterize CVD risk in HCT survivors, setting the stage for tailored interventions to prevent CVD with its attendant morbidity and mortality.

Clinically Relevant Physical Benefits of Exercise Interventions in Breast Cancer Survivors. Curr Oncol Rep. 2016;18:12. [PMID: 26769117 DOI: 10.1007/s11912-015-0496-3]

Evidence is currently limited for the effect of exercise on breast cancer clinical outcomes. However, several of the reported physical benefits of exercise, including peak oxygen consumption, functional capacity, muscle strength and lean mass, cardiovascular risk factors, and bone health, have established associations with disability, cardiovascular disease risk, morbidity, and mortality. This review will summarize the clinically relevant physical benefits of exercise interventions in breast cancer survivors and discuss recommendations for achieving these benefits. It will also describe potential differences in intervention delivery that may impact outcomes and, lastly, describe current physical activity guidelines for cancer survivors.

Assessing utility of exercise test in determining exercise prescription in adolescent and adult patients with repaired tetralogy of fallot

Parameters from cardiopulmonary exercise test (CPET) are useful prognostic factors for patients with repaired tetralogy of fallot (TOF). Its application in exercise prescription remains unclear. This study sought to define its role. We made current exercise recommendations in repaired TOF patients according to European Society of Cardiology (ESC) guideline, which were based on ventricular function, pressure/volume load, pulmonary artery pressure, hypoxemia and arrhythmic burden both at rest and during exercise. CPET parameters (peak oxygen consumption, oxygen uptake efficiency plateau, and E/CO₂ slope), along with cardiothoracic ratio, ventricular arrhythmia, QRS duration and NYHA functional status, were used to calculate "score to exercise". 112 repaired TOF adolescent and adult aged 32.6 ± 10.8 (14.05- to 56.99-year-old, median 30.1) years received exercise recommendations by ESC guideline, which suggested high, moderate and low intensity sports for 45 (40.2 %), 45 (40.2 %), and 22 (19.6 %) patients, respectively. The optimal cut-off values were 67 and 77 % for peak VO₂, 86 and 100 % for OUEP, 22 and 28 for E/CO₂ slope to correlate to the exercise intensity recommendation. But, individual CPET parameter had low consistency (41-46 %) in making decisions of exercise intensity compared to ESC recommendations. Using the "score to exercise", the consistency rate could be increased to 74.1 %. With "score to exercise" recommended exercise intensity, follow-up result revealed no adverse event related to sports. Individual CPET parameter did not correlate well to the exercise recommendation from ESC. We proposed a scoring system, "score to exercise", which incorporates three CPET parameters with cardiothoracic ratio, ventricular arrhythmia, QRS duration and NYHA functional status. Score to exercise is easy to be assessed and provides useful information for exercise recommendation in patients with repaired TOF.

Is cardiopulmonary exercise testing essential to indicate ventricular assist device implantation in patients with INTERMACS profile 4-7?

Cardiopulmonary exercise testing (CPXT) is a promising tool for predicting 2-year cardiac death or ventricular assist device (VAD) implantation in patients assigned to INTERMACS profile 4-7. However, CPXT is not available in all hospitals. We evaluated 130 patients <65 years old with advanced heart failure assigned to INTERMACS profile 4-7 who underwent CPXT. CPXT scores (0-8 points), which we created recently, and the Seattle HF Model (SHFM) scores were both significant predictors of 2-year cardiac death or VAD implantation (14 events) by Cox-regression analysis (P < 0.05 for both) and had comparable areas under the curve (AUCs) in receiver operating characteristic analyses (0.811 vs. 0.737, P > 0.05). The combination score: age <46 years and serum sodium concentration <137 mEq/L, both of which were significant predictors of cardiac death or VAD implantation by uni/multivariate Cox-regression analyses, had a significantly higher AUC than did CPXT scores (0.909, P < 0.05). In a validation study, the AUC of the combination score was comparable with that of SHFM among 52 patients <65 years old receiving adaptive servo-ventilator treatment (0.753 vs. 0.794, P > 0.05). In conclusion, VAD indication may be discussed without CPXT in patients <65 years old with INTERMACS profile 4-7 at least in the current Japanese situation.

Feasibility of a 12-month-exercise intervention during and after radiation and chemotherapy in cancer patients: impact on quality of life, peak oxygen consumption, and body composition

Background

Accumulating evidence suggests that exercise is effective in treating many of the acute and chronic side effects of anti-cancer therapy. A recent meta-analysis supported the use of exercise to prevent or treat fatigue and lymphoedema and to improve functional status in breast cancer patients.

Patients and methods

This trial was intended as a controlled, prospective feasibility study evaluating the impact of physical exercise (PE) in cancer patients during and after treatment with radio- and chemotherapy. Inclusion criteria were previous or ongoing treatment for cancer, motivation for PE of 0.5-1hour duration at least twice weekly for at least 3 months. Continuation of PE was encouraged thereafter. Every three months the following endpoints were assessed: Peak oxygen consumption as measured by supervised cardiopulmonary exercise test, body composition and quality of life.

Results

A total of 45 patients were included with a median age of 49 years. Forty were female and five male. Cancer types were: Breast cancer (n = 30/67 %), gastrointestinal cancer (n = 5/12 %), other types (n = 10/22 %). Thirty-eight (84 %) of the patients were included during curative treatment of their disease. Seven (16 %) were considered palliative. Adherence to the PE-programme longer than 6 months was noted for 41/45 (91 %) of the patients. Intensity of PE was thrice weekly in 32/45 (71 %), twice weekly in 11/45 (24 %). Two of 45 patients (5 %) had no PE. Mean peak oxygen consumption increased from 18.8 ± 5.6 ml/min/kg to 20.5 ± 3 ml/min/kg and 19.9 ± 4.7 ml/min/kg at 3 months (p = 0.005) and 12 months (p = 0.003), respectively.

Median fat mass decreased from 30.7 ± 15 kg to 28.9 ± 15 kg and 29.5 ± 13 kg at 3 months (p = 0.001) and 12 months (p = 0.017), respectively. Global health status scores increased from a median baseline value of 54.9 ± 16.3 to 66.4 ± 14 % and 68.0 ± 20.3 % at 3 months (p = 0.001) and 12 months (p = 0.002), respectively.

Conclusion

This exercise programme in cancer patients with 2–3 weekly supervised sessions over three months was well feasible and demonstrated measurable improvement of oxygen consumption, body composition and quality of life. In addition, a 90 %-adherence rate to the PE-programme beyond 6 months was encouraging. Further randomized prospective data in a larger patient population will be collected comparing the impact of two versus four months supervision.

Electronic supplementary material

The online version of this article (doi:10.1186/s13014-016-0619-5) contains supplementary material, which is available to authorized users.

Robotically assisted treadmill exercise training for improving peak fitness in chronic motor incomplete spinal cord injury: A randomized controlled trial

OBJECTIVE

To assess the effectiveness of robotically assisted body weight supported treadmill training (RABWSTT) for improving cardiovascular fitness in chronic motor incomplete spinal cord injury (CMISCI).

DESIGN

Pilot prospective randomized, controlled clinical trial.

SETTING

Outpatient rehabilitation specialty hospital.

PARTICIPANTS

Eighteen individuals with CMISCI with American Spinal Injury Association (ASIA) level between C4 and L2 and at least one-year post injury. Interventions CMISCI participants were randomized to RABWSTT or a home stretching program (HSP) three times per week for three months. Those in the home stretching group were crossed over to three months of RABWSTT following completion of the initial three month phase.

OUTCOME MEASURES

Peak oxygen consumption (peak VO(2)) was measured during both robotic treadmill walking and arm cycle ergometry: twice at baseline, once at six weeks (mid-training) and twice at three months (post-training). Peak VO(2) values were normalized for body mass.

RESULTS

The RABWSTT group improved peak VO(2) by 12.3% during robotic treadmill walking (20.2 ± 7.4 to 22.7 ± 7.5 ml/kg/min, P = 0.018), compared to a non-significant 3.9% within group change observed in HSP controls (P = 0.37). Neither group displayed a significant change in peak VO2 during arm cycle ergometry (RABWSTT, 8.5% (P = 0.25); HSP, 1.76% (P = 0.72)). A repeated measures analysis showed statistically significant differences between treatments for peak VO(2) during both robotic treadmill walking (P = 0.002) and arm cycle ergometry (P = 0.001).

CONCLUSION

RABWSTT is an effective intervention model for improving peak fitness levels assessed during robotic treadmill walking in persons with CMISCI.

Relationship between aerobic capacity and cardiovascular disease risk factors in Thai men and women with normolipidemia and dyslipidemia

[Purpose] This research aimed to investigate the relationship between aerobic capacity (VO_2,peak) and cardiovascular risk factors in normolipidemic and dyslipidemic Thai men and women. [Subjects and Methods] We recruited 104 dyslipidemic and 100 healthy participants. Fasting blood samples were analyzed for lipid and blood glucose levels. Anthropometry, blood pressure, and body composition were measured before exercise. Each subject underwent exercise testing to determine VO_{2, peak}. Heart rate (HR) was recorded throughout the exercise test. [Results] Dyslipidemic participants had a lower VO_{2, peak} than normolipidemic participants (p<0.01). In normolipidemic male participants, VO_{2, peak} was positively correlated with high density lipoprotein cholesterol (HDL-C) levels and negatively correlated with low density lipoprotein cholesterol (LDL-C) levels and triglycerides to HDL-cholesterol (TG/HDL-C) ratios; in females, VO_{2, peak} was negatively correlated with age, total cholesterol, and LDL-C. In dyslipidemic males, VO_{2, peak} was positively correlated with HDL-C levels and negatively correlated with age, LDL-C and TG levels, and percent body fat; in females, VO_{2, peak} was positively correlated with resting HR and heart rate recovery and negatively correlated with age, TG/HDL-C, and waist circumference. [Conclusion] There was a relationship between aerobic capacity and cardiovascular disease risk factors in both normolipidemic and dyslipidemic participants. This relationship was affected by gender.

Adolescents who were born extremely preterm demonstrate modest decreases in exercise capacity

AIM

We aimed to investigate exercise capacity in adolescents who were born extremely preterm and to study changes through puberty and associations with neonatal data, exercise habits and lung function.

METHODS

This Norwegian population-based controlled cohort study focused on all infants (n = 35) born at a gestational age of ≤ 28 weeks or with a birthweight of ≤ 1000 grams in 1991-1992, together with matched term-born controls. Participants underwent spirometry and a maximal cardiopulmonary treadmill exercise test at 10 and 18 years.

RESULTS

At 18 years of age, mean (95% confidence interval) peak oxygen consumption (peak VO2 ) was 42.3 (39.2-45.4) vs 45.3 (41.3-49.3) mL/kg/min in the preterm- and term-born groups, while the completed treadmill distance was 915 (837-992) vs 1017 (912-1122) metres. Peak VO2 was unrelated to neonatal factors and current lung function. Changes between 10 and 18 were similar in the two groups, and positive associations between exercise habits and peak VO2 developed during the period.

CONCLUSION

Exercise capacity was modestly reduced in adolescents born extremely preterm, but the values were considered normal in most participants. Changes during puberty were similar to those observed for term controls, and the findings suggest similar trainability.

Diagnostic value of the six-minute walk test (6MWT) in grown-up congenital heart disease (GUCH): Comparison with clinical status and functional exercise capacity

BACKGROUND

Exercise testing for the assessment of functional capacity plays an important role in long-term follow-up of GUCH patients. CPX is the favored modality for decision-making recommended in the current guidelines. In contrast to this complex method, the 6 MWT is a simple, easy-to-perform, safe, and commonly available exercise test. Although well-established in various cardiopulmonary diseases, the diagnostic impact of the 6 MWT in GUCH patients is not known so far.

METHODS

102 GUCH patients were evaluated by 6 MWT and CPX simultaneously. Clinical symptoms were assessed, according to the NYHA classification. Additionally, an echocardiography study, and selected cardiac blood tests (N-terminal pro-brain natriuretic peptide (NT-proBNP), high-sensitive Troponin T) were performed.

RESULTS

Ranges of six-minute walk distance (6 MWD) and peak oxygen consumption (peakVO2) were 116-765 m and 6.4-36.2 ml/kg/min, respectively. 6 MWD and peakVO2 showed a close correlation (r=0.72, 95% CI, 0.63 to 0.79). Patients with a peakVO2 of ≤ 15.5 ml/kg/min were excellently identified by 6 MWT (c-value=0.82). A cut-off value of 482 m was optimal to predict reduced peakVO2. In multivariate regression analysis, 6 MWD and NYHA class were identified as relevant predictors of peakVO2. In subgroup analysis, Eisenmenger patients achieved the shortest 6 MWD (280, SD 178 m).

CONCLUSION

In our study population of GUCH patients, the 6 MWD shows a close correlation to peakVO2, and an excellent prediction of reduced peakVO2. Thus, it seems to be an easy-to-perform and reliable screening parameter to evaluate functional capacity of these patients (Controlled Clinical Trials number, NCT02193243).

Impact of obesity and Down syndrome on peak heart rate and aerobic capacity in youth and adults

Individuals with Down syndrome (DS) exhibit reduced aerobic capacity with reduced peak heart rate (HR_peak). This condition is often coexistent with higher level of obesity compared to individuals without DS. The purpose of this study is to investigate the effects of obesity and Down syndrome (DS) on peak heart rate (HR_peak) and peak oxygen consumption (VO_2peak) in children and adults both with and without intellectual disabilities (ID)s. VO_2peak and HR_peak from individualized treadmill tests on 654 individuals were analyzed. Body mass index was used to categorize individuals' weight status using standard cut-offs. DS groups had the lowest HR_peak (167bpm±14, p<0.05) compared to individuals with (183bpm±12) without ID (187bpm±12). Obesity did not affect HR_peak among adults and children with DS. VO_2peak was lower among individuals with DS (25.2mL/kg/min±6.3, p<0.05) when compared individuals with (37.0mL/kg/min±10.5) and without ID (36.1mL/kg/min±10.4). Obese adults with DS had lower VO_2peak (24.3mL/kg/min±6.9, p=0.001) compared to the normal weight (26.7±7.1mL/kg/min) and overweight groups (27.0mL/kg/min±6.1) with DS. Conversely, in children, obesity level did not impact VO_2peak in individuals with DS. Our results suggest that DS attenuates both VO_2peak and HR_peak, regardless of obesity status and age group. However, obesity was associated with lower VO_2peak in all adults, but not in children with DS.

The effect of exergaming on vascular function in children

OBJECTIVES

To assess whether exergaming can induce measurable changes in heart rate (HR), energy expenditure (EE), and flow-mediated dilation (FMD) arterial function in healthy children.

STUDY DESIGN

Fifteen children (8 males, 10.1 ± 0.7 years, body mass index 17.9 ± 2.4 kg.m(-2)) undertook a graded exercise test and 2 × 15 minute exergaming sessions (Xbox 360-Kinect); high intensity exergaming (HiE, Kinect Sports-200 m Hurdles) and low intensity exergaming (LoE, Kinect Sports-Ten Pin Bowling). Brachial artery FMD, a measure of endothelial function and arterial health, was measured before and immediately after each exergaming intervention. Actihearts were used to measure EE and HR during game play and a physical activity enjoyment scale assessed enjoyment.

RESULTS

Average HR during HiE (146 ± 11 beats per minute) was greater than during LoE (104 ± 11 beats per minute, P < .05), a pattern reinforced by EE data (HiE 294.6 ± 75.2 J.min(-1).kg(-1), LoE 73.7 ± 44.0 J.min(-1).kg(-1), P < .05). FMD decreased after HiE (P < .05), whereas no change was observed following LoE. Subjects reported no differences in enjoyment between LoE and HiE.

CONCLUSION

HiE, but not LoE, induced large HR and EE responses that were associated with effects on vascular function. This study suggests that an acute bout of HiE exergaming may provide a substrate for beneficial arterial adaptations in children.

Speeding of pulmonary VO2 on-kinetics by light-to-moderate-intensity aerobic exercise training in chronic heart failure: clinical and pathophysiological correlates

BACKGROUND

Pulmonary VO2 on-kinetics during light-to-moderate-intensity constant-work-rate exercise, an experimental model mirroring energetic transitions during daily activities, has been shown to speed up with aerobic exercise training (AET) in normal subjects, but scant data are available in chronic heart failure (CHF).

METHODS AND RESULTS

Thirty CHF patients were randomized to 3 months of light-to-moderate-intensity AET (CHF-AET) or control (CHF-C). Baseline and end-protocol evaluations included i) one incremental cardiopulmonary exercise test with near infrared spectroscopy analysis of peak deoxygenated hemoglobin+myoglobin concentration changes (Δ[deoxy(Hb+Mb)]) in vastus lateralis muscle, ii) 8 light-to-moderate-intensity constant-work-rate exercise tests for VO2 on-kinetics phase I duration, phase II τ, and mean response time (MRT) assessment, and iii) circulating endothelial progenitor cell (EPC) measurement. Reference values were obtained in 7 age-matched normals (N). At end-protocol, phase I duration, phase II τ, and MRT were significantly reduced (-12%, -22%, and -19%, respectively) and peak VO2, peak Δ[deoxy(Hb+Mb)], and EPCs increased (9%, 20%, and 98%, respectively) in CHF-AET, but not in CHF-C. Peak Δ[deoxy(Hb+Mb)] and EPCs relative increase correlated significantly to that of peak VO2 (r=0.61 and 0.64, respectively, p<0.05).

CONCLUSIONS

Light-to-moderate-intensity AET determined a near-normalization of pulmonary VO2 on-kinetics in CHF patients. Such a marked plasticity has important implications for AET intensity prescription, especially in patients more functionally limited and with high exercise-related risk. The AET-induced simultaneous improvement of phase I and phase II, associated with an increase of peak peripheral oxygen extraction and EPCs, supports microcirculatory O2 delivery impairment as a key factor determining exercise intolerance in CHF.

Blunted heart rate recovery is improved following exercise training in overweight adults with obstructive sleep apnea

BACKGROUND

Obstructive sleep apnea (OSA) predisposes individuals to cardiovascular morbidity, and cardiopulmonary exercise test (CPET) markers prognostic for cardiovascular disease have been found to be abnormal in adults with OSA. Due to the persistence of OSA and its cardiovascular consequences, whether the cardiovascular adaptations normally conferred by exercise are blunted in adults not utilizing established OSA treatment is unknown. The aims of this study were to document whether OSA participants have abnormal CPET responses and determine whether exercise modifies these CPET markers in individuals with OSA.

METHODS

The CPET responses of 43 sedentary, overweight adults (body mass index [BMI]>25) with untreated OSA (apnea-hypopnea index [AHI]≥ 15) were compared against matched non-OSA controls (n=9). OSA participants were then randomized to a 12-week exercise training (n=27) or stretching control treatment (n=16), followed by a post-intervention CPET. Measures of resting, exercise, and post-exercise recovery heart rate (HRR), blood pressure, and ventilation, as well as peak oxygen consumption (VO(2peak)), were obtained.

RESULTS

OSA participants had blunted HRR compared to non-OSA controls at 1 (P=.03), 3 (P=.02), and 5-min post-exercise (P=.03). For OSA participants, exercise training improved VO2 peak (P=.04) and HRR at 1 (P=.03), 3 (P<.01), and 5-min post-exercise (P<.001) compared to control. AHI change was associated with change in HRR at 5-min post-exercise (r=-.30, P<.05), but no other CPET markers.

CONCLUSIONS

These results suggest that individuals with OSA have autonomic dysfunction, and that exercise training, by increasing HRR and VO2 peak, may attenuate autonomic imbalance and improve functional capacity independent of OSA severity reduction.