Causes and Consequences of Interindividual Response Variability: A Call to Apply a More Rigorous Research Design in Acute Exercise-Cognition Studies

Impact of resistance and high-intensity interval training on body composition, physical function, and temporal dynamics of adaptation in older women with impaired cardiometabolic health: a randomized clinical trial

PURPOSE

Physical inactivity is associated with reduced physical fitness (PF) in older women with impaired cardiometabolic health. Although exercise has been shown to improve PF, interindividual variability in response and adaptation changes over time remain unclear. This study evaluated the effects of eight weeks of resistance training (RT) and high-intensity interval training (HIIT) on body composition, isometric strength, and the 6-minute walk test (6MWT) in older women with impaired cardiometabolic health. Additionally, the study explored the reduction of non-responders (NRs) and adaptation changes over time.

METHODS

This randomized clinical trial involved 36 older women (64 ± 8.4 years; BMI: 31.8 ± 5.5) with impaired cardiometabolic health, divided into RT-G (n = 12; 62 ± 7 years; BMI: 32.2 ± 4.1), HIIT-G (n = 12; 66 ± 10 years; BMI: 31.2 ± 4.1), and CG (n = 12; 64 ± 9 years; BMI: 31.8 ± 6) groups. RT-G performed elastic band exercises, and HIIT-G performed cycle ergometer intervals. BMI, body fat, lean mass, isometric strength, and 6MWT were measured at baseline and at four and eight weeks. The Student's t-test was applied for normally distributed variables and the Mann-Whitney U test for non-normal variables. Intra- and inter-group differences were analyzed using a two-way repeated measures ANOVA, considering group, time, and their interaction. Post-hoc comparisons were conducted using the Bonferroni test. Individual responses (IR) were calculated using the equation proposed by Hopkins: SDIR = √(SDExp2 - SDCon2). The prevalence of responders (Rs) and non-responders (NRs) was expressed as a percentage, and percentage changes from baseline to weeks four and eight were used to evaluate adaptations dynamics.

RESULTS

By week eight, isometric strength in RT-G significantly improved from 21.3 ± 4.4 to 24.37 ± 3.99 kg (p = 0.027; 95% CI: 1.8, 4.3 kg; Cohen's d = 0.731) and 6MWT distance in HIIT-G increased from 441.0 ± 48.9 to 480.0 ± 53.0 m. (p = 0.002; 95% CI: 22, 55 m; Cohen's d = 0.757). Both protocols reduced NRs for body fat, lean mass, and 6MWT. Responders showed greater adaptations in the first four weeks, stabilizing by week eight.

CONCLUSION

RT and HIIT improved PF in older women with impaired cardiometabolic health, reducing NRs in terms of body composition and 6MWT over eight weeks, with similar adaptation changes over time among the responders. These findings highlight the importance of individualized exercise interventions to maximize health benefits.

TRIAL REGISTRATION

This study was part of a trial registered at ClinicalTrials.gov (ID: NCT06201273). Date: 22/12/2023.

Proteomic associations with cognitive variability as measured by the Wisconsin Card Sorting Test in a healthy Thai population: A machine learning approach

Inter-individual cognitive variability, influenced by genetic and environmental factors, is crucial for understanding typical cognition and identifying early cognitive disorders. This study investigated the association between serum protein expression profiles and cognitive variability in a healthy Thai population using machine learning algorithms. We included 199 subjects, aged 20 to 70, and measured cognitive performance with the Wisconsin Card Sorting Test. Differentially expressed proteins (DEPs) were identified using label-free proteomics and analyzed with the Linear Model for Microarray Data. We discovered 213 DEPs between lower and higher cognition groups, with 155 upregulated in the lower cognition group and enriched in the IL-17 signaling pathway. Subsequent bioinformatic analysis linked these DEPs to neuroinflammation-related cognitive impairment. A random forest model classified cognitive ability groups with an accuracy of 81.5%, sensitivity of 65%, specificity of 85.9%, and an AUC of 0.79. By targeting a specific Thai cohort, this research provides novel insights into the link between neuroinflammation and cognitive performance, advancing our understanding of cognitive variability, highlighting the role of biological markers in cognitive function, and contributing to developing more accurate machine learning models for diverse populations.

Exercising4Cognition: Can Short Bouts of Aerobic Exercise Improve Cognitive Performance in Healthy Adults for Primary Health Prevention? Previous Findings and Suggestions for the Future

Background: Regular physical activity (PA) and regular exercise (RE) are essential for an active and healthy lifestyle. Additionally, the short-term effects have been investigated to understand how an acute bout of exercise impacts cognitive processing, an important aspect of mental health and well-being. Previous studies have confirmed positive effects. However, several exercise factors and human factors can influence this relationship. Aim/Methods/Results: This perspective paper has three main objectives: firstly, discussing the exercise and human factors that influence exercise-cognition effects significantly across studies according to previous reviews and meta-analytic studies and how this influence could be explained theoretically; secondly, highlighting important knowledge gaps and research questions for future research; and thirdly, discussing what conclusion can be drawn for cognitive health promotion. A particular focus is given to the effects of acute bouts of aerobic exercise and healthy adults as an important target group for primary health prevention. Conclusions: The summary of previous findings shows that the effects of an acute bout of aerobic exercise on cognitive performance in healthy adults depend on (a) exercise factors such as the duration and intensity of the acute bout of exercise, (b) cognitive factors such as the type of cognitive task and domain of cognitive functions, and (c) individual factors such as the physical activity of the individuals. Still, open questions concern the ideal duration, intensity and timing of the acute bout of exercise. In particular, more research is needed to determine whether and how aerobic exercises of short duration and an intensity above and especially below moderate intensity improve cognitive functions in healthy adults. Methodologically, these factors should be addressed by multimethod designs that consider intra- and interindividual comparisons and different response levels (self-report, behavioral, psychophysiological). In conclusion, answering these questions could pave the way for recommendations on how healthcare professionals should prescribe brief aerobic exercise as a cognitive health booster in healthy young adults. To this end, concepts of extended arousal and neurovisceral integration are useful framework models to include individual factors, like self-regulatory abilities of the individual and how these influence exercise-cognition interactions and exercise motivation during, pre-to-post and across testing sessions.

Characteristics of the differential response to exercise in adults with restless legs syndrome

OBJECTIVE/BACKGROUND

Restless legs syndrome (RLS) is a prevalent, sensorimotor sleep disorder characterized by the irresistible urge to move that is temporarily relieved by movement. Despite evidence for the benefits of exercise in RLS, inter-individual variation in the response to exercise exists, whereby some people experience symptom improvement while others report exacerbations. The present study examined factors that may account for differences in perceived responses to exercise in RLS.

PATIENTS/METHODS

Participants (N = 527) completed a nationwide survey with items assessing RLS, physical activity, sedentary levels, and experiences with RLS responsiveness to exercise. Logistic regression analyses examined associations between individual characteristics (e.g., age, sex) and perceptions of improvement and exacerbation with exercise. Exploratory analyses examined characteristics associated with perceived positive responsiveness (i.e., exercise only improves RLS) or negative responsiveness (i.e., exercise only worsens RLS).

RESULTS

Ordinal logistic regression identified lower RLS severity (OR = 0.83, p = 0.044), higher prevalence of a condition that could cause secondary RLS (OR = 1.76, p = 0.005), lower prevalence of periodic limb movements (OR = 0.52, p = 0.001), and higher physical activity levels (OR = 1.47, p < 0.001) as significant, independent predictors of exercise improving RLS symptoms. Individual feature ordinal logistic regression identified female sex as significantly associated with exercise exacerbating symptoms (OR = 0.62, p = 0.008). Exploratory logistic regression identified people with higher BMI (OR = 0.69, p = 0.019) and higher RLS severity (OR = 0.70, p = 0.026) had lower odds of being positive responders to exercise.

CONCLUSIONS

The present study presents factors that might account for individual differences in the response to exercise. Overall, our results suggest that milder cases of RLS (lower severity, absence of PLMs), people with secondary forms of RLS, and those with a lower BMI may perceive exercise as more beneficial for symptoms. These should be considered in exercise-based management aimed at managing symptoms as the collective body of research supports the benefits of exercise in adults with RLS.

Interindividual Variability Response to Resistance and High-Intensity Interval Training on Blood Pressure Reduction in Hypertensive Older Adults

BACKGROUND

This study evaluated the effects of resistance training (RT) and high-intensity interval training (HIIT) on systolic (SBP) and diastolic blood pressure (DBP) in hypertensive older adults undergoing pharmacological therapy over four and eight weeks. We compared the efficacy of RT and HIIT in reducing non-responders (NRs) between weeks 4 and 8 and analyzed time-course adaptations in NRs and responders (Rs).

METHODS

Thirty-nine participants were randomized into RT-G (n = 13), HIIT-G (n = 13), or control (CG, n = 13) groups. RT utilized elastic bands, and HIIT involved cycle ergometers, with three weekly 30 min sessions for 8 weeks. SBP and DBP were measured before intervention and at weeks 4 and 8, respectively. Individual responses were classified as NRs or Rs using the Hopkins method (SDIR = √[SDExp2-SDCon2]). Time-course adaptations were evaluated.

RESULTS

Both the RT-G and HIIT-G reduced SBP at 8 weeks (RT-G: -13 mmHg; [ES: 1.12]; HIIT-G: -12 mmHg [ES: 0.8]; both p < 0.05). The proportion of NRs for SBP decreased from 46% to 38% in RT-G and 69% to 46% in HIIT-G. Rs showed a peak SBP reduction at 4 weeks (-14.7 and -25.5 mmHg), stabilizing by week 8 (-22.8 and -19.6 mmHg) in RT-G and HIIT-G, respectively.

CONCLUSION

Eight weeks of RT and HIIT effectively reduced SBP and NR prevalence, with time-course adaptations favoring Rs.

Underpowered studies in muscle metabolism research: Determinants and considerations

Biomedical research frequently employs null hypothesis testing to determine whether an observed difference in a sample is likely to exist in the broader population. Null hypothesis testing generally assumes that differences between groups or interventions are non-existent, unless proven otherwise. Because biomedical studies with human subjects are often limited by financial and logistical resources, they tend to have low statistical power, i.e. a low probability of statistically confirming a true difference. As a result, small but potentially clinically important differences may be overseen or ignored simply due to the absence of a statistically significant difference. This absence is often misinterpreted as 'equivalence' of treatments. In this educational paper, we will use practical examples related to the effects of exercise and nutrition on muscle protein metabolism to illustrate the most important determinants of statistical power, as well as their implications for both investigators and readers of scientific articles. Changes in muscle mass occur at a relatively slow rate, making it practically challenging to detect differences between treatment groups in a long-term setting. One way to make it 'easier' to differentiate between groups and hence increase statistical power is to have a sufficiently long study duration to allow treatment effects to become apparent. This is especially relevant when comparing treatments with relatively small expected differences such as the effect of modest changes in daily protein intake. Secondly, one could try to minimize the variance and response heterogeneity within groups, for example by using strict inclusion criteria and standardization protocols (e.g., meal provision), by using cross-over designs, or even within-subject designs where two interventions are compared simultaneously (e.g., studying an exercised limb vs a contralateral control limb) although this might limit the generalizability of the findings (e.g. such single-limb exercise training is not common in practice). In terms of data interpretation, investigators should obviously refrain from drawing strong conclusions from underpowered studies. Yet, such studies still provide valuable data for meta-analyses. Finally, because muscle protein synthesis rates are highly responsive to anabolic stimuli, acute metabolic studies are more sensitive to detect potentially clinically relevant differences in the anabolic response between treatments. Apart from further elaborating on these topics, this educational article encourages readers to more critically question null findings and scientists to more clearly discuss limitations that may have compromised statistical power.

Induced discomfort promotes executive function while walking with(out) an artificial neuromuscular impairment

Neuromotor disorders can degrade one's ability to locomote and attend to salient stimuli in the environment. Many disorders are physiologically complex, making it difficult to tease apart interactions between motor adaptation and executive function processes. We address this challenge by giving participants a controlled artificial impairment, using electrical stimulation to produce an uncomfortable disruption in normal muscular coordination during locomotion. While adapting to this gait perturbation, participants performed an executive function task containing neutral and affectively charged stimuli. The artificial impairment was counterbalanced against control and sham (discomfort-only stimulation) walking conditions. Our twofold hypothesis that discomfort would selectively tax hot, emotionally charged executive function and motor adaptation would challenge cold, logical executive function was not supported. However, we found that the discomfort experienced with both stimulation conditions improved participants' ability to inhibit distracting information, enhancing this aspect of executive function, and the effect did not depend on whether the task was affectively charged. Moderate discomfort during physical activity may have improved inhibitory control by increasing arousal, a known factor mediating executive function. These results show that using a sensorimotor perturbation that acts internally and bridges multiple physiological domains, including discomfort, can reveal effects not seen with purely environmental manipulations. The broader implications are that when high cognitive performance is needed during physical activity, it may be beneficial to, quite literally, operate outside one's comfort zone.NEW & NOTEWORTHY When locomotor and cognitive tasks compete for shared neural resources, cognitive-motor interference may impair performance in both domains. To understand how impairments that cause pain or change neuromotor control impact cognition during locomotion, we gave healthy adults an uncomfortable, artificial neuromuscular impairment while they walked and completed a task dependent on ignoring distracting stimuli. We found that discomfort enhanced participants' ability to ignore distractions, providing new insight into the mediators of cognition during impaired movement.

Gut microbial metabolism in Alzheimer's disease and related dementias

Multiple studies over the last decade have established that Alzheimer's disease and related dementias (ADRD) are associated with changes in the gut microbiome. These alterations in organismal composition result in changes in the abundances of functions encoded by the microbial community, including metabolic capabilities, which likely impact host disease mechanisms. Gut microbes access dietary components and other molecules made by the host and produce metabolites that can enter circulation and cross the blood-brain barrier (BBB). In recent years, several microbial metabolites have been associated with or have been shown to influence host pathways relevant to ADRD pathology. These include short chain fatty acids, secondary bile acids, tryptophan derivatives (such as kynurenine, serotonin, tryptamine, and indoles), and trimethylamine/trimethylamine N-oxide. Notably, some of these metabolites cross the BBB and can have various effects on the brain, including modulating the release of neurotransmitters and neuronal function, inducing oxidative stress and inflammation, and impacting synaptic function. Microbial metabolites can also impact the central nervous system through immune, enteroendocrine, and enteric nervous system pathways, these perturbations in turn impact the gut barrier function and peripheral immune responses, as well as the BBB integrity, neuronal homeostasis and neurogenesis, and glial cell maturation and activation. This review examines the evidence supporting the notion that ADRD is influenced by gut microbiota and its metabolites. The potential therapeutic advantages of microbial metabolites for preventing and treating ADRD are also discussed, highlighting their potential role in developing new treatments.

Linear jerk variability evaluation in measurements of motor control trainability: Could kinematic variables encompass information about strength and dynamic balance?

As the natural conclusion of talent identification in sports, talent development is the process that involves improving biomechanical capacities and bio-motor abilities. The development progress can be objectively assessed and monitored through measurements of trainability. This study introduces a practical methodology to assess motor control as a trainable factor using kinematic data. The study focused on establishing the relationship between kinematic data and changes in muscle strength and dynamic balance. It illustrates how wearable technology can assess trainability during a functional training programme. Twenty-six female university students were selected and divided into intervention and control groups to investigate motor control trainability. The intervention group performed step aerobics exercises for 24 sessions. A single inertial measurement unit (IMU) mounted on S1 captured the oscillatory motion profiles of the centre of mass during these rhythmic exercises. Analysis revealed that the amplitude of linear jerk variability in different anatomical planes could reflect core and lower limb muscle strengthening caused by training. Furthermore, the results indicated that the dynamic balance adaptation to the changing tempo throughout the training programme was dictated primarily by step width. The mediolateral linear jerk variability reflected this adaptation. The minimum instrumentation approach proposed by this study could prove very practical for the talent development monitoring. The methodology illustrates how the recorded kinematic data from an appropriately placed single IMU could become an information-rich source for the coach to monitor, assess and quantify the trainee's progress during long-term athletic development.

A mechanistic understanding of cognitive performance deficits concurrent with vigorous intensity exercise

This study aimed to evaluate whether cerebral oxygenation of the prefrontal cortex and associative-dissociative focus while completing the task mediate changes in cognition during exercise. Seventy-five young college-aged adults participated in this within-subjects randomized cross-over two-arm experimental design. During each session, participants completed a Stroop task four separate times: at baseline, two times during the exercise session, and at post-test. The experimental arm session involved participants cycling first at a moderate intensity, followed by cycling at a vigorous intensity. The active control arm session involved participants cycling at a very light intensity to ensure any effects were attributable to the level of exertion rather than the control of motor coordination. Cerebral oxygenation of the prefrontal cortex was assessed using fNIRS, while associate-dissociate attention was assessed using a self-report scale to provide insight into two hypothesized mechanisms which may contribute to alterations in cognition during exercise. Replicating well-established findings, results showed that during vigorous-intensity exercise, accuracy rates decreased for the most cognitively demanding conditions of the Stroop task, while reaction times were generally shorter compared to baseline. Neither shifting of attention in response to the dual-task nor prefrontal cortex oxygenation were observed to mediate cognitive deficits associated with vigorous exercise.

'Exerkines': A Comprehensive Term for the Factors Produced in Response to Exercise

Regular exercise and physical activity are now considered lifestyle factors with positive effects on human health. Physical activity reduces disease burden, protects against the onset of pathologies, and improves the clinical course of disease. Unlike pharmacological therapies, the effects mediated by exercise are not limited to a specific target organ but act in multiple biological systems simultaneously. Despite the substantial health benefits of physical training, the precise molecular signaling processes that lead to structural and functional tissue adaptation remain largely unknown. Only recently, several bioactive molecules have been discovered that are produced following physical exercise. These molecules are collectively called "exerkines". Exerkines are released from various tissues in response to exercise, and play a crucial role in mediating the beneficial effects of exercise on the body. Major discoveries involving exerkines highlight their diverse functions and health implications, particularly in metabolic regulation, neuroprotection, and muscle adaptation. These molecules, including peptides, nucleic acids, lipids, and microRNAs, act through paracrine, endocrine, and autocrine pathways to exert their effects on various organs and tissues. Exerkines represent a complex network of signaling molecules that mediate the multiple benefits of exercise. Their roles in metabolic regulation, neuroprotection, and muscle adaptation highlight the importance of physical activity in maintaining health and preventing disease.

The Best of Two Worlds to Promote Healthy Cognitive Aging: Definition and Classification Approach of Hybrid Physical Training Interventions

A healthy lifestyle can be an important prerequisite to prevent or at least delay the onset of dementia. However, the large number of physically inactive adults underscores the need for developing and evaluating intervention approaches aimed at improving adherence to a physically active lifestyle. In this regard, hybrid physical training, which usually combines center- and home-based physical exercise sessions and has proven successful in rehabilitative settings, could offer a promising approach to preserving cognitive health in the aging population. Despite its potential, research in this area is limited as hybrid physical training interventions have been underused in promoting healthy cognitive aging. Furthermore, the absence of a universally accepted definition or a classification framework for hybrid physical training interventions poses a challenge to future progress in this direction. To address this gap, this article informs the reader about hybrid physical training by providing a definition and classification approach of different types, discussing their specific advantages and disadvantages, and offering recommendations for future research. Specifically, we focus on applying digital technologies to deliver home-based exercises, as their use holds significant potential for reaching underserved and marginalized groups, such as older adults with mobility impairments living in rural areas.

Early physical rehabilitation dosage in the intensive care unit associates with hospital outcomes after critical COVID-19

OBJECTIVE

To examine the relationship between physical rehabilitation parameters including an approach to quantifying dosage with hospital outcomes for patients with critical COVID-19.

DESIGN

Retrospective practice analysis from March 5, 2020, to April 15, 2021.

SETTING

Intensive care units (ICU) at four medical institutions.

PATIENTS

n = 3780 adults with ICU admission and diagnosis of COVID-19.

INTERVENTIONS

We measured the physical rehabilitation treatment delivered in ICU and patient outcomes: (1) mortality; (2) discharge disposition; and (3) physical function at hospital discharge measured by the Activity Measure-Post Acute Care (AM-PAC) "6-Clicks" (6-24, 24 = greater functional independence). Physical rehabilitation dosage was defined as the average mobility level scores in the first three sessions (a surrogate measure of intensity) multiplied by the rehabilitation frequency (PT + OT frequency in hospital).

MEASUREMENTS AND MAIN RESULTS

The cohort was a mean 64 ± 16 years old, 41% female, mean BMI of 32 ± 9 kg/m2 and 46% (n = 1739) required mechanical ventilation. For 2191 patients who received rehabilitation, the dosage and AM-PAC at discharge were moderately, positively associated (Spearman's rho [r] = 0.484, p < 0.001). Multivariate linear regression (model adjusted R2 = 0.68, p < 0.001) demonstrates mechanical ventilation (β = - 0.86, p = 0.001), average mobility score in first three sessions (β = 2.6, p < 0.001) and physical rehabilitation dosage (β = 0.22, p = 0.001) were predictive of AM-PAC scores at discharge when controlling for age, sex, BMI, and ICU LOS.

CONCLUSIONS

Greater physical rehabilitation exposure early in the ICU is associated with better physical function at hospital discharge.

Biological basis and treatment of frailty and sarcopenia

In an ageing society, the importance of maintaining healthy life expectancy has been emphasized. As a result of age-related decline in functional reserve, frailty is a state of increased vulnerability and susceptibility to adverse health outcomes with a serious impact on healthy life expectancy. The decline in skeletal muscle mass and function, also known as sarcopenia, is key in the development of physical frailty. Both frailty and sarcopenia are highly prevalent in patients not only with advanced age but also in patients with illnesses that exacerbate their progression like heart failure (HF), cancer, or dementia, with the prevalence of frailty and sarcopenia in HF patients reaching up to 50-75% and 19.5-47.3%, respectively, resulting in 1.5-3 times higher 1-year mortality. The biological mechanisms of frailty and sarcopenia are multifactorial, complex, and not yet fully elucidated, ranging from DNA damage, proteostasis impairment, and epigenetic changes to mitochondrial dysfunction, cellular senescence, and environmental factors, many of which are further linked to cardiac disease. Currently, there is no gold standard for the treatment of frailty and sarcopenia, however, growing evidence supports that a combination of exercise training and nutritional supplement improves skeletal muscle function and frailty, with a variety of other therapies being devised based on the underlying pathophysiology. In this review, we address the involvement of frailty and sarcopenia in cardiac disease and describe the latest insights into their biological mechanisms as well as the potential for intervention through exercise, diet, and specific therapies.

A Genotype-Phenotype Model for Predicting Resistance Training Effects on Leg Press Performance

This study develops a comprehensive genotype-phenotype model for predicting the effects of resistance training on leg press performance. A cohort of physically inactive adults (N=193) underwent 12 weeks of resistance training, and measurements of maximum isokinetic leg press peak force, muscle mass, and thickness were taken before and after the intervention. Whole-genome genotyping was performed, and genome-wide association analysis identified 85 novel SNPs significantly associated with changes in leg press strength after training. A prediction model was constructed using stepwise linear regression, incorporating seven lead SNPs that explained 40.4% of the training effect variance. The polygenic score showed a significant positive correlation with changes in leg press strength. By integrating genomic markers and phenotypic indicators, the comprehensive prediction model explained 75.4% of the variance in the training effect. Additionally, five SNPs were found to potentially impact muscle contraction, metabolism, growth, and development through their association with REACTOME pathways. Individual responses to resistance training varied, with changes in leg press strength ranging from -55.83% to 151.20%. The study highlights the importance of genetic factors in predicting training outcomes and provides insights into the potential biological functions underlying resistance training effects. The comprehensive model offers valuable guidance for personalized fitness programs based on individual genetic profiles and phenotypic characteristics.

Early physical rehabilitation dosage in the IntensiveCare Unit predicts hospital outcomes after criticalCOVID-19

Objective

to examine the relationship between physical rehabilitation parameters including a novel approach to quantifying dosage with hospital outcomes for patients with critical COVID-19.

Design

Retrospective practice analysis from March 5, 2020, to April 15, 2021.

Setting

Intensive care units (ICU) at four medical institutions.

Patients

n = 3,780 adults with ICU admission and diagnosis of COVID-19.

Interventions

We measured the physical rehabilitation treatment delivered in ICU and patient outcomes: 1) mortality; 2) discharge disposition; and 3) physical function at hospital discharge measured by the Activity Measure-Post Acute Care (AM-PAC) "6-Clicks" (6-24, 24=greater functional independence). Physical rehabilitation dosage was defined as the average mobility level scores in the first three sessions (a surrogate measure of intensity) multiplied by the rehabilitation frequency (PT + OT frequency in hospital).

Measurements and Main Results

The cohort was a mean 64 ± 16 years old, 41% female, mean BMI of 32 ± 9 kg/m2 and 46% (n=1739) required mechanical ventilation. For 2191 patients with complete data, rehabilitation dosage and AM-PAC at discharge were moderately, positively associated (Spearman's rho [r] = 0.484, p < 0.001). Multivariate linear regression (model adjusted R2= 0.68, p <0.001) demonstrates mechanical ventilation (β = -0.86, p = 0.001), average mobility score in first three sessions (β = 2.6, p <0.001) and physical rehabilitation dosage (β = 0.22, p = 0.001) were predictive of AM-PAC scores at discharge when controlling for age, sex, BMI, and ICU LOS.

Conclusions

Greater physical rehabilitation exposure early in the ICU is associated with physical function at hospital discharge.

Effects of an acute bout of cycling on different domains of cognitive function

The literature suggesting acute exercise benefits cognitive function has been largely confined to single cognitive domains and measures of reliant on measures of central tendencies. Furthermore, studies suggest cognitive intra-individual variability (IIV) to reflect cognitive efficiency and provide unique insights into cognitive function, but there is limited knowledge on the effects of acute exercise on IIV. To this end, this study examined the effects of acute exercise on three different cognitive domains, executive function, implicit learning, and hippocampal-dependent memory function using behavioral performance and event-related potentials (ERPs). Furthermore, this study also sought to explore the effects of an acute bout of exercise on IIV using the RIDE algorithm to separate signals into individuals components based on latency variability. Healthy adult participants (N=20; 26.3±4.8years) completed a randomized cross-over trial with seated rest or 30min of high intensity cycling. Before and after each condition, participants completed a cognitive battery consisting of the Eriksen Flanker task, implicit statistical learning task, and a spatial reconstruction task. While exercise did not affect Flanker or spatial reconstruction performance, there were exercise related decreases in accuracy (F=5.47; P=0.040), slowed reaction time (F=5.18; P=0.036), and decreased late parietal positivity (F=4.26; P=0.046). However, upon adjusting for performance and ERP variability, there were exercise related decreases in Flanker reaction time (F=24.00; P<0.001), and reduced N2 amplitudes (F=13.03; P=0.002), and slower P3 latencies (F=3.57; P=0.065) for incongruent trials. These findings suggest that acute exercise may impact cognitive IIV as an adaptation to maintain function following exercise.

Are There Interindividual Responses of Cardiovascular Disease Risk Markers to Acute Exercise? A Replicate Crossover Trial

PURPOSE

Using a replicated crossover design, we quantified the response heterogeneity of postprandial cardiovascular disease risk marker responses to acute exercise.

METHODS

Twenty men (mean (SD) age, 26 (6) yr; body mass index, 23.9 (2.4) kg·m -2 ) completed four 2-d conditions (two control, two exercise) in randomized orders. On days 1 and 2, participants rested and consumed two high-fat meals over 9 h. Participants ran for 60 min (61 (7)% of peak oxygen uptake) on day 1 (6.5 to 7.5 h) of both exercise conditions. Time-averaged total area under the curve (TAUC) for triacylglycerol, glucose, and insulin were calculated from 11 venous blood samples on day 2. Arterial stiffness and blood pressure responses were calculated from measurements at baseline on day 1 and at 2.5 h on day 2. Consistency of individual differences was explored by correlating the two replicates of control-adjusted exercise responses for each outcome. Within-participant covariate-adjusted linear mixed models quantified participant-by-condition interactions and individual response SDs.

RESULTS

Acute exercise reduced mean TAUC-triacylglycerol (-0.27 mmol·L -1 ·h; Cohen's d = 0.29, P = 0.017) and TAUC-insulin (-25 pmol·L -1 ·h; Cohen's d = 0.35, P = 0.022) versus control, but led to negligible changes in TAUC-glucose and the vascular outcomes (Cohen's d ≤ 0.36, P ≥ 0.106). Small-to-moderate, but nonsignificant, correlations were observed between the two response replicates ( r = -0.42 to 0.15, P ≥ 0.066). We did not detect any individual response heterogeneity. All participant-by-condition interactions were P ≥ 0.137, and all individual response SDs were small with wide 95% confidence intervals overlapping zero.

CONCLUSIONS

Large trial-to-trial within-subject variability inhibited detection of consistent interindividual variability in postprandial metabolic and vascular responses to acute exercise.

Personalized redox biology: Designs and concepts

Personalized interventions are regarded as a next-generation approach in almost all fields of biomedicine, such as clinical medicine, exercise, nutrition and pharmacology. At the same time, an increasing body of evidence indicates that redox processes regulate, at least in part, multiple aspects of human physiology and pathology. As a result, the idea of applying personalized redox treatments to improve their efficacy has gained popularity among researchers in recent years. The aim of the present primer-style review was to highlight some crucial yet underappreciated methodological, statistical, and interpretative concepts within the redox biology literature, while also providing a physiology-oriented perspective on personalized redox biology. The topics addressed are: (i) the critical issue of investigating the potential existence of inter-individual variability; (ii) the importance of distinguishing a genuine and consistent response of a subject from a chance finding; (iii) the challenge of accurately quantifying the effect of a redox treatment when dealing with 'extreme' groups due to mathematical coupling and regression to the mean; and (iv) research designs and analyses that have been implemented in other fields, and can be reframed and exploited in a redox biology context.

Escherichia coli-induced inflammatory responses are temperature-dependent in human whole blood ex vivo

Systemic inflammatory conditions are often associated with hypothermia or hyperthermia. Therapeutic hypothermia is used in post-cardiac arrest and some other acute diseases. There is a need for more knowledge concerning the effect of various temperatures on the acute inflammatory response. The complement system plays a crucial role in initiating the inflammatory response. We hypothesized that temperatures above and below the physiologic 37 °C affect complement activation and cytokine production ex vivo. Lepirudin-anticoagulated human whole blood from 10 healthy donors was incubated in the presence or absence of Escherichia coli at different temperatures (4 °C, 12 °C, 20 °C, 33 °C, 37 °C, 39 °C, and 41 °C). Complement activation was assessed by the terminal C5b-9 complement complex (TCC) and the alternative convertase C3bBbP using ELISA. Cytokines were measured using a 27-plex assay. Granulocyte and monocyte activation was evaluated by CD11b surface expression using flow cytometry. A consistent increase in complement activation was observed with rising temperature, reaching a maximum at 41 °C, both in the absence (C3bBbP p < 0.05) and presence (C3bBbP p < 0.05 and TCC p < 0.05) of E. coli. Temperature alone did not affect cytokine production, whereas incubation with E. coli significantly increased cytokine levels of IL-1β, IL-2, IL-6, IL-8, IFN-γ, and TNF at temperatures > 20 °C. Maximum increase occurred at 39 °C. However, a consistent decrease was observed at 41 °C, significant for IL-1β (p = 0.003). Granulocyte CD11b displayed the same temperature-dependent pattern as cytokines, with a corresponding increase in endothelial cell apoptosis and necrosis. Thus, blood temperature differentially determines the degree of complement activation and cytokine release.

Acute exercise and children's cognitive functioning: What is the optimal dose of cognitive challenge?

Acute bouts of exercise have the potential to benefit children's cognition. Inconsistent evidence on the role of qualitative exercise task characteristics calls for further investigation of the cognitive challenge level in exercise. Thus, the study aim was to investigate which "dose" of cognitive challenge in acute exercise benefits children's cognition, also exploring the moderating role of individual characteristics. In a within-subject experimental design, 103 children (Mage = 11.1, SD = 0.9, 48% female) participated weekly in one of three 15-min exergames followed by an Attention Network task. Exergame sessions were designed to keep physical intensity constant (65% HRmax) and to have different cognitive challenge levels (low, mid, high; adapted to the ongoing individual performance). ANOVAs performed on variables that reflect the individual functioning of attention networks revealed a significant effect of cognitive challenge on executive control efficiency (reaction time performances; p = .014, ƞ2p = .08), with better performances after the high-challenge condition compared to lower ones (ps < .015), whereas alerting and orienting were unaffected by cognitive challenge (ps > .05). ANOVAs performed on variables that reflect the interactive functioning of attention networks revealed that biological sex moderated cognitive challenge effects. For males only, the cognitive challenge level influenced the interactive functioning of executive control and orienting networks (p = .004; ƞ2p = .07). Results suggest that an individualized and adaptive cognitively high-challenging bout of exercise is more beneficial to children's executive control than less challenging ones. For males, the cognitive challenge in an acute bout seems beneficial to maintain executive control efficiency also when spatial attention resources cannot be validly allocated in advance. Results are interpreted referring to the cognitive stimulation hypothesis and arousal theory.

Point/counterpoint: Arterial blood pressure response to exercise does relate to exercise-induced improvement in cognitive function

Exercise is a beneficial intervention to prevent cognitive dysfunction. However, an optimal exercise prescription for preventing dementia has not been established because the physiological mechanism(s) of exercise-induced improvements in cognitive function remains unclear. Interestingly, our recent study demonstrated that individuals with a higher exercise pressor response exhibit less exercise-induced cognitive improvement, suggesting that individual differences in cardiovascular responses to exercise or its associated physiological factors, may be related to exercise-induced alterations in cognitive function. Therefore, consideration of individual cardiovascular responses is warranted to develop appropriate exercise prescriptions for a given individual to prevent cognitive dysfunction.

Need strength, perceived need support, stress symptomatology, and performance in the context of oral exams: A typological approach

Introduction

Based on self-determination theory, we investigated whether examinees are classifiable into profiles based on basic need strength and perceived need support that differ in stress parameters and achievement in the context of a standardized oral exam.

Methods

92 students reported their basic need strength before and perceived need support provided by the examiner once after the exam. Students indicated their emotions and stress perception at four measurement points and we measured their saliva cortisol concurrently, analyzing stress-related changes over time.

Results

Latent class analyses revealed two higher-quality (low/high, high/high) and two lower-quality (low/low, high/low) need strength/need support classes. Physio-affective stress development was typical of exam situations. Higher-quality classes that met or exceeded the needs displayed more beneficial stress and emotion response patterns than lower-quality classes. Gain-related emotions mediated achievement in the higher-quality classes.

Discussion

Need-supportive examiners can promote student well-being and achievement when they succeed in providing high need satisfaction.

Tai Chi practice enables prefrontal cortex bilateral activation and gait performance prioritization during dual-task negotiating obstacle in older adults

BACKGROUND

With aging, the cognitive function of the prefrontal cortex (PFC) declined, postural control weakened, and fall risk increased. As a mind-body exercise, regular Tai Chi practice could improve postural control and effectively prevent falls; however, underlying brain mechanisms remained unclear, which were shed light on by analyzing the effect of Tai Chi on the PFC in older adults by means of functional near-infrared spectroscopy (fNIRS).

METHODS

36 healthy older adults without Tai Chi experience were divided randomly into Tai Chi group and Control group. The experiment was conducted four times per week for 16 weeks; 27 participants remained and completed the experiment. Negotiating obstacle task (NOT) and negotiating obstacle with cognitive task (NOCT) were performed pre- and post-intervention, and Brodmann area 10 (BA10) was detected using fNIRS for hemodynamic response. A three-dimensional motion capture system measured walking speed.

RESULTS

After intervention in the Tai Chi group under NOCT, the HbO2 concentration change value (ΔHbO2) in BA10 was significantly greater (right BA10: p = 0.002, left BA10: p = 0.001), walking speed was significantly faster (p = 0.040), and dual-task cost was significantly lower than pre-intervention (p = 0.047). ΔHbO2 in BA10 under NOCT was negatively correlated with dual-task cost (right BA10: r = -0.443, p = 0.021, left BA10: r = -0.448, p = 0.019). There were strong negative correlations between ΔHbO2 and ΔHbR under NOCT either pre-intervention (left PFC r = -0.841, p < 0.001; right PFC r = -0.795, p < 0.001) or post-intervention (left PFC r = -0.842, p < 0.001; right PFC r = -0.744, p < 0.001).

CONCLUSION

Tai Chi practice might increase the cognitive resources in older adults through the PFC bilateral activation to prioritize gait performance during negotiating obstacles under a dual-task condition.

Acute effects of virtual reality treadmill training on gait and cognition in older adults: A randomized controlled trial

INTRODUCTION

Everyday walking often involves walking with divided attention (i.e., dual-tasking). Exercise interventions for older adults should mimic these simultaneous physical and cognitive demands. This proof-of-concept study had a two-fold purpose: 1) identify acute cognitive and gait benefits of a single session of virtual reality treadmill training (VRTT), relative to conventional treadmill training (CTT), and 2) identify differences between those who reduced dual-task costs (i.e., responders) on gait or cognition and those who did not, after the session.

METHODS

Sixty older adults were randomized to complete a single 30-minute session of VRTT (n = 30, 71.2±6.5 years, 22 females) or CTT (n = 30, 72.0±7.7 years, 21 females). Pre- and post-exercise session, participants performed single-task walking, single-task cognitive, and dual-task walking trials while gait and cognition were recorded. Gait variables were gait speed and gait speed variability. Cognition variables were response reaction time, response accuracy, and cognitive throughput. Dual-task effects (DTE) on gait and cognition variables were also calculated.

RESULTS

Post-exercise, there were no group differences (all p>0.05). During single- and dual-task trials, both groups walked faster (single-task: F(1, 58) = 9.560, p = 0.003; dual-task: F(1, 58) = 19.228, p<0.001), responded more quickly (single-task: F(1, 58) = 5.054, p = 0.028; dual-task: F(1, 58) = 8.543, p = 0.005), and reduced cognitive throughput (single-task: F(1, 58) = 6.425, p = 0.014; dual-task: F(1, 58) = 28.152, p<0.001). Both groups also exhibited reduced DTE on gait speed (F(1, 58) = 8.066, p = 0.006), response accuracy (F(1, 58) = 4.123, p = 0.047), and cognitive throughput (F(1, 58) = 6.807, p = 0.012). Gait responders and non-responders did not differ (all p>0.05), but cognitive responders completed fewer years of education (t(58) = 2.114, p = 0.039) and better information processing speed (t(58) = -2.265, p = 0.027) than cognitive non-responders.

CONCLUSIONS

The results indicate that both VRTT and CTT may acutely improve gait and cognition. Therefore, older adults will likely benefit from participating in either type of exercise. The study also provides evidence that baseline cognition can impact training effects on DTE on cognition.

Associations of the Lipidome with Ageing, Cognitive Decline and Exercise Behaviours

One of the most recognisable features of ageing is a decline in brain health and cognitive dysfunction, which is associated with perturbations to regular lipid homeostasis. Although ageing is the largest risk factor for several neurodegenerative diseases such as dementia, a loss in cognitive function is commonly observed in adults over the age of 65. Despite the prevalence of normal age-related cognitive decline, there is a lack of effective methods to improve the health of the ageing brain. In light of this, exercise has shown promise for positively influencing neurocognitive health and associated lipid profiles. This review summarises age-related changes in several lipid classes that are found in the brain, including fatty acyls, glycerolipids, phospholipids, sphingolipids and sterols, and explores the consequences of age-associated pathological cognitive decline on these lipid classes. Evidence of the positive effects of exercise on the affected lipid profiles are also discussed to highlight the potential for exercise to be used therapeutically to mitigate age-related changes to lipid metabolism and prevent cognitive decline in later life.

Going digital - a commentary on the terminology used at the intersection of physical activity and digital health

In recent years digital technologies have become a major means for providing health-related services and this trend was strongly reinforced by the current Coronavirus disease 2019 (COVID-19) pandemic. As it is well-known that regular physical activity has positive effects on individual physical and mental health and thus is an important prerequisite for healthy aging, digital technologies are also increasingly used to promote unstructured and structured forms of physical activity. However, in the course of this development, several terms (e.g., Digital Health, Electronic Health, Mobile Health, Telehealth, Telemedicine, and Telerehabilitation) have been introduced to refer to the application of digital technologies to provide health-related services such as physical interventions. Unfortunately, the above-mentioned terms are often used in several different ways, but also relatively interchangeably. Given that ambiguous terminology is a major source of difficulty in scientific communication which can impede the progress of theoretical and empirical research, this article aims to make the reader aware of the subtle differences between the relevant terms which are applied at the intersection of physical activity and Digital Health and to provide state-of-art definitions for them.

Acute and Chronic Exercise Effects on Human Memory: What We Know and Where to Go from Here

Although the acquisition, storage, and retrieval of memories was once thought to happen within a single memory system with multiple processes operating on it, it is now believed that memory is comprised of both distinct and interacting brain systems [...].