Changes In Cardiorespiratory Fitness Research Articles

Effect of Excessive Screen Time on Cardiorespiratory Fitness in Children: A Longitudinal Study.

Background: This study investigated the effect of different components of screen time (mobile phone use, TV/video viewing, and video gaming) on cardiorespiratory fitness (CRF) development in children aged 9–12 years. Methods: This was a two-year longitudinal study conducted with 175 children (49.7% girls, mean age = 9.5) in Japan. CRF was assessed using a 20 m shuttle run test conducted at baseline and again at follow-up. Children were categorized as “Good” or “Poor” based on the change in CRF scores for each gender. Screen time was assessed using a self-reported questionnaire at baseline and termed as “high” if children reported ≥ 2 h/day. Univariate and multivariate logistic regression analyses were performed after adjusting for gender, physical activity, and time of data collection. Results: Children scoring “high” on mobile phone use had lower odds of being categorized as “Good” in CRF change (crude odds ratio (OR): 0.34; 95% confidence interval (CI): 0.15–0.90 (adjusted OR: 0.33; 95% CI: 0.12–0.91)). There were no significant effects of TV/video viewing (crude OR: 1.54; 95% CI: 0.84–2.81) and video gaming (crude OR: 0.98; 95% CI: 0.48–1.97) on changes in CRF. Conclusions: Limiting excessive mobile phone usage might be important for ensuring healthy development of CRF in children.

Impact of a physician-led exercise programme on quality of life, muscle mass and clinical response in inflammatory bowel disease patients during induction with disease-modifying therapy: a study protocol

IntroductionBiologic and small-molecule therapies have revolutionised the treatment of moderate-to-severe inflammatory bowel disease (IBD). A significant proportion of patients experience early or delayed treatment failure. Patients with IBD with greater...

P05-01 Change in cardiorespiratory fitness in midlife and incident hypertension

BackgroundLow cardiorespiratory fitness (CRF) is associated with higher blood pressure and risk of incident hypertension. However, existing literature has mainly investigated CRF at baseline. For HEPA initiatives, it is important to know how change in CRF in midlife associate with incident hypertension, and whether this varies between sexes, age and baseline CRF.Methods91,728 individuals (20-79 years, 48% women, free from hypertension at baseline) from the Swedish workforce who had completed two health profile assessments in a nationwide occupational health service screening between 1986 and 2019 were included. CRF (assessed as VO2max) was estimated using a submaximal cycle test. Change in CRF between the two tests was expressed as % change in absolute CRF (L·min-1) per year and categorized as “maintainers” (-1% to 1% change/year), “decreases” (≥-1% change/year) or “increasers” (≥1% change/year). Incident hypertension was defined as having a blood pressure >140/90 mmHg or diagnosed with hypertension at the second test. Binary logistic regression was used to assess OR (95% CI) for hypertension at the second test between maintainers, decreases and increasers. All analyses were adjusted for sex, age, heart medication, time between tests, education, and change in other lifestyle variables between the two tests (stress, diet, exercise, smoking).ResultsCompared to maintainers (set as reference), OR for decreases was 1.27 (1.18-1.38) and increasers OR 0.99 (0.89-1.09). Isolating midlife participants (40-60 years), OR for decreasers was 1.47 (1.30-1.66) and increasers OR 0.75 (0.64-0.86). Looking at sex differences, male decreasers had OR 1.24 (1.12-1.36) and female decreasers OR 1.36 (1.20-1.56), compared to maintainers, while OR for male and female increasers was 0.93 (0.83-1.03) and 0.97 (0.83-1.13). For participants with low CRF at baseline (<32·kg-1·min-1), OR for decreasers was 1.70 (1.51-1.92) and increasers 1.32 (1.18-1.49). Corresponding ORs in those with high CRF at baseline were 0.90 (0.80-1.02) and 0.43 (0.26-0.71).ConclusionsDecrease in CRF with >1% per year associated with significant higher risk for incident hypertension, while maintaining or increasing CRF had similar risk associations. This was seen in both men and women, different age-groups and baseline level of CRF. Health enhancing promotion strategies to maintain or increase CRF level is highly clinically relevant.

Exercise engagement drives changes in cognition and cardiorespiratory fitness after 8 weeks of aerobic training in sedentary aging adults at risk of cognitive decline.

BackgroundWith our aging population, many individuals are at risk of developing age-related cognitive decline. Physical exercise has been demonstrated to enhance cognitive performance in aging adults. This study examined the effects of 8 weeks of aerobic exercise on cognitive performance and cardiorespiratory fitness in sedentary aging adults at risk for cognitive decline.MethodsFifty-two participants (age 62.9 ± 6.8, 76.9% female) engaged in eight weeks of moderate-to high-intensity exercise (19 in-person, 33 remotely). Global cognition was measured by the Repeatable Battery for the Assessment of Neuropsychological Status, the Delis-Kaplan Executive Function System, and the Digit Span subtest of the Wechsler Adult Intelligence Scale (WAIS) Fourth Edition. Cardiorespiratory fitness was measured via heart rate recovery at minute 1 (HRR1) and 2 (HRR2), and exercise engagement (defined as percent of total exercise time spent in the prescribed heart rate zone). We measured pre and post changes using paired t-tests and mixed effects models, and investigated the association between cardiorespiratory and cognitive performance using multiple regression models. Cohen's d were calculated to estimate effect sizes.ResultsOverall, 63.4 % of participants demonstrated high engagement (≥ 70% total exercise time spent in the prescribed heart rate zone). There were significant pre-post improvements in verbal fluency and verbal memory, and a significant decrement in working memory, but these were associated with small effect sizes (Cohen's d <0.5). Concerning cardiorespiratory fitness, there was a pre-to-post significant improvement in HRR1 (p = 0.01, d = 0.30) and HRR2 (p < 0.001, d = 0.50). Multiple regressions revealed significant associations between cardiorespiratory and cognitive performance, but all were associated with small effect sizes (Cohen's d < 0.5). Interestingly, there were significant between-group differences in exercise engagement (all p < 0.001), with remote participants demonstrating greater exercise engagement than in-person participants.ConclusionImprovements in cognition and cardiorespiratory fitness were observed after 8 weeks of moderate to high-intensity exercise in aging adults. These results suggest that committing to a regular exercise regimen, even for a brief two-month period, can promote improvements in both cardiorespiratory fitness and cognitive performance, and that improvements are driven by exercise engagement.

Endurance Training Improves GLP-1 Sensitivity and Glucose Tolerance in Overweight Women.

Context and objectiveObesity and inactivity are risk factors for developing impaired glucose tolerance characterized by insulin resistance and reduced beta-cell function. The stimulatory effect of glucagon-like peptide 1 (GLP-1) on insulin secretion is also impaired in obese, inactive individuals. The aim of this study was to investigate whether endurance training influences beta-cell sensitivity to GLP-1.Participants and interventionTwenty-four female participants, age 46 ± 2 years, body mass index 32.4 ± 0.9 kg/m2, and maximal oxygen consumption 24.7 ± 0.8 mL/kg/min participated in a 10-week exercise training study.MethodsBeta-cell sensitivity to GLP-1 was assessed in a subset of participants (n = 6) during a 120-minute hyperglycemic glucose clamp (8.5 mM) including a 1-hour GLP-1 (7-36 amide) infusion (0.4 pmol/kg/min). Changes in glucose tolerance, body composition, and cardiorespiratory fitness were assessed by oral glucose tolerance tests (OGTTs), dual-energy X-ray absorptiometry scans, magnetic resonance scans, and maximal oxygen consumption (VO2max) tests, respectively.ResultsThe c-peptide response to infusion of GLP-1 increased 28 ± 3% (P < 0.05) toward the end of the hyperglycemic clamp. The insulin response remained unchanged. Training improved glucose tolerance and reduced GLP-1, insulin, and glucagon levels during the OGTTs. Training increased VO2max (from 24.7 ± 0.8 to 27.0 ± 0.7 mL/kg/min; P < 0.05) and reduced visceral fat volume (from 4176 ± 265 to 3888 ± 266 cm3; P < 0.01).ConclusionAlong with improved glycemic control, endurance training improved beta-cell sensitivity to GLP-1 in overweight women. The study was deemed not to constitute a clinical trial and was not registered as such.

Physical and Psychological Outcomes of Patients Undergoing Traditional Cardiac Rehabilitation and Intensive Cardiac Rehabilitation.

Both traditional cardiac rehabilitation (TCR) and intensive cardiac rehabilitation (ICR) have proven benefits for patients with cardiovascular disease. The aim of this study was to compare ICR versus TCR on cardiac rehabilitation (CR) outcomes in patients with cardiovascular disease. In a retrospective cohort study of 970 patients (n = 251, ICR; n = 719, TCR) who were referred for CR between January 2018 and December 2019, 693 (71.4%) patients completed it. The TCR sessions were 90 min (60-min exercise) three times/wk for 12 wk, while ICR sessions were 4 hr (60-min exercise) two times/wk for 9 wk. Primary endpoints were change in cardiorespiratory fitness (CRF) (by difference in exercise prescription metabolic equivalents [METs] between the last session and the average of the second and third sessions), anxiety (Generalized Anxiety Disorder-7) scores, percent depression (Patient Health Questionnaire-9 or Center for Epidemiologic Studies Depression Scale) scores, and health status (36-item Short Form Health Survey physical and mental composite scores). Linear regression adjusted for imbalanced baseline characteristics (age, race, and diagnosis of angina). Of the 693 patients who completed CR (ICR = 204/251 [81%] vs TCR = 489/719 [68%], P < .01), mean age was 66 yr and 31% were female. Patients in TCR had a higher improvement in CRF (CR session METs: ICR +1.5 ± 1.2 vs TCR +1.9 ± 1.5, P < .01) but no difference in health status scores. Conversely, patients in ICR had more reduction in anxiety scores (-2 ± 4 vs -1 ± 3, P < .01) and percent reduction in depression scores (-8.3 ± 13.7% vs -5.0 ± 11.7%, P < .01) than patients in TCR. Patients in TCR had higher improvement in CRF while patients in ICR had higher improvement in anxiety and depression scores.

The association of change in peak oxygen uptake with use of psychotropics in community-dwelling older adults - The Generation 100 study

BackgroundThe use of psychotropics is high among the older population and may have detrimental effects on their physical and mental health. Cardiorespiratory fitness (CRF) is a strong and modifiable measure of health and declines with age. We aimed to study the association of change in CRF with use of psychotropics in community-dwelling older adults.MethodsWe analyzed longitudinal data from 1531 older adults from the Generation 100 study, aged 70–77 years at inclusion, and with a permanent address in Trondheim, Norway. Data on objectively measured peak oxygen uptake (VO2peak) were linked with register data from the Norwegian Prescription Database on prescribed psychotropics. The included psychotropics were antidepressants (N06A), antipsychotics (N05A), anxiolytics (N05B), hypnotics and sedatives (N05C), and N03AE (benzodiazepine derivatives). Analyses were done on any psychotropics as one group, and on the following separate groups: antidepressants (N06A), benzodiazepines (N05BA, N05CD, and N03AE), and z-hypnotics (N05CF). Peak oxygen uptake was measured four times over a five-year period and corresponding medication use was measured as defined daily doses (DDD). A random effects estimator was applied to investigate the association of change in VO2peak with the use of psychotropics.ResultsWe found a statistically significant curvilinear association of change in VO2peak with use of any psychotropics and antidepressants. For VO2peak up to ~ 40 ml/kg/min, each 1 ml/kg/min increase was associated by a 3.3 DDD and 2.5 DDD decrease in use of any psychotropics and antidepressants, respectively. A bottoming-out effect was found and increases in VO2peak above ~ 40 ml/kg/min showed increased use of any psychotropics and antidepressants. However, the association of change in VO2peak with use was stronger for changes in the lower continuum of VO2peak levels and decreased with increasing VO2peak. No statistically significant association of change in VO2peak with use of benzodiazepines and z-hypnotics were found. However, because of a non-randomized design, we cannot rule out the possibility of confounding by indication.ConclusionsThe results of this study show a curvilinear association of change in VO2peak with use of any psychotropics and antidepressants in older adults. This relationship adds a new viewpoint on the adverse effects of psychotropic use and should be considered in interventions and policies aimed at reducing psychotropic medication use among the older population.

Effects of regular sauna bathing in conjunction with exercise on cardiovascular function: a multi-arm, randomized controlled trial.

Regular exercise and sauna bathing have each been shown to improve cardiovascular function in clinical populations. However, experimental data on the cardiovascular adaptations to regular exercise in conjunction with sauna bathing in the general population are lacking. Therefore, we compared the effects of exercise and sauna bathing to regular exercise using a multi-arm randomized controlled trial. Participants (n = 47) aged 49 ± 9 with low physical activity levels and at least one traditional cardiovascular disease (CVD) risk factor were randomly assigned (1:1:1) to guideline-based regular exercise and 15-min postexercise sauna (EXS), guideline-based regular exercise (EXE), or control (CON) for 8 wk. The primary outcomes were blood pressure (BP) and cardiorespiratory fitness (CRF). Secondary outcomes included fat mass, total cholesterol levels, and arterial stiffness. EXE had a greater change in CRF (+6.2 mL/kg/min; 95% CI, +4.2 to +8.3 mL/kg/min) and fat mass but no differences in BP when compared with CON. EXS displayed greater change in CRF (+2.7 mL/kg/min; 95% CI, +0.2 to +5.3 mL/kg/min), lower systolic BP (-8.0 mmHg; 95% CI, -14.6 to -1.4 mmHg), and lower total cholesterol levels compared with EXE. Regular exercise improved CRF and body composition in sedentary adults with CVD risk factors. However, when combined with exercise, sauna bathing demonstrated a substantially supplementary effect on CRF, systolic BP, and total cholesterol levels. Sauna bathing is a valuable lifestyle tool that complements exercise for improving CRF and decreasing systolic BP. Future research should focus on the duration and frequency of exposure to ascertain the dose-response relationship.

Interindividual Differences in Trainability and Moderators of Cardiorespiratory Fitness, Waist Circumference, and Body Mass Responses: A Large-Scale Individual Participant Data Meta-analysis.

Although many studies have assumed variability reflects variance caused by exercise training, few studies have examined whether interindividual differences in trainability are present following exercise training. The present individual participant data (IPD) meta-analysis sought to: (1) investigate the presence of interindividual differences in trainability for cardiorespiratory fitness (CRF), waist circumference, and body mass; and (2) examine the influence of exercise training and potential moderators on the probability that an individual will experience clinically important differences. The IPD meta-analysis combined data from 1879 participants from eight previously published randomized controlled trials. We implemented a Bayesian framework to: (1) test the hypothesis of interindividual differences in trainability by comparing variability in change scores between exercise and control using Bayes factors; and (2) compare posterior predictions of control and exercise across a range of moderators (baseline body mass index (BMI) and exercise duration, intensity, amount, mode, and adherence) to estimate the proportions of participants expected to exceed minimum clinically important differences (MCIDs) for all three outcomes. Bayes factors demonstrated a lack of evidence supporting a high degree of variance attributable to interindividual differences in trainability across all three outcomes. These findings indicate that interindividual variability in observed changes are likely due to measurement error and external behavioural factors, not interindividual differences in trainability. Additionally, we found that a larger proportion of exercise participants were expected to exceed MCIDs compared with controls for all three outcomes. Moderator analyses identified that larger proportions were associated with a range of factors consistent with standard exercise theory and were driven by mean changes. Practitioners should prescribe exercise interventions known to elicit large mean changes to increase the probability that individuals will experience beneficial changes in CRF, waist circumference and body mass.

Quantile Differences in the Age-Related Decline in Cardiorespiratory Fitness Between Sexes in Adults Without Type 2 Diabetes Mellitus in the United States

ObjectiveTo comprehensively assess the extent to which the decline in cardiorespiratory fitness (CRF) with age differs between sexes. Participants and MethodsThis study used data from the Aerobics Center Longitudinal Study, conducted between September 1974 and August 2006, consisting primarily of White adults from middle-to-upper socioeconomic strata restricted to adults without type 2 diabetes mellitus (33,742 men and 9,415 women). Quantile regression models were used to estimate the differences in age-associated changes in CRF between the sexes, estimated using a maximal treadmill test. ResultsFor adults aged up to 45 years, significant differences in slopes relating to age and CRF between men and women were observed for all adjusted percentiles of CRF other than the 90th percentile; women reported significantly greater declines in CRF per year. For those aged 45-60 years and those older than 60 years, no significant differences in age-related declines in CRF were observed between the sexes. ConclusionThis study found that compared with men, the onset of decline in CRF was found to occur earlier and at lower CRF percentiles in women. This is of particular concern, given that compared with men, women already tend to have lower CRF levels. These findings suggest that maintaining the levels of physical activity sufficient to maintain moderate-to-high levels of fitness is particularly important for women earlier during adulthood.

Body fat percentage, cardiorespiratory fitness and arterial blood pressure in children and adolescents: a longitudinal analysis

BackgroundA better understanding of how cardiorespiratory fitness (CRF) and adiposity interact to associate with arterial blood pressure over time remains inconclusive. Thus, the aim of the present study was to examine whether changes in CRF moderates the association between body fat percentage (BF%) and arterial blood pressure in children and adolescents.MethodsThis is an observational longitudinal study with 407 children and adolescents aged 8–17 years followed-up for three years from a city in Southern Brazil. Participants were evaluated in 2011 and 2014. CRF was measured by validated field-based tests following the Projeto Esporte Brazil protocols and peak oxygen uptake (VO2peak) was estimated. BF% was determined by the measures of tricipital and subscapular skinfolds using equations according to sex. Systolic and diastolic blood pressure (SBP, DBP) were measured with a sphygmomanometer according to standard procedures. Moderation analyses included multiple linear regression models adjusted for sex, age, pubertal status, height, socioeconomic level, skin color, and the arterial blood pressure variable itself at baseline.ResultsIt was observed a significant inverse association between VO2peak at baseline with SBP (β = − 0.646 CI95% = − 0.976 − 0.316) and DBP (β = − 0.649 CI95% = − 0.923 − 0.375) at follow-up and a positive association between BF% at baseline with SBP (β = 0.274; CI95% = 0.094 0.455) and DBP (β = 0.301; CI95% = 0.150 0.453) at follow-up. In addition, results indicated a significant interaction term between changes in VO2peak and BF% at baseline with both SBP (p = 0.034) and DBP at follow-up (p = 0.011), indicating that an increase of at least 0.35 mL/kg/min and 1.78 mL/kg/min in VO2peak attenuated the positive relationship between BF% with SBP and DBP.ConclusionCRF moderates the relationship between BF% and SBP and DBP in children and adolescents.

High-intensity interval training to promote cerebral oxygenation and affective valence during exercise in individuals with obesity

ABSTRACT Left/right prefrontal cortex (PFC) activation is linked to positive/negative affects, respectively. Besides, larger left PFC oxygenation during exercise relates to higher cardiorespiratory fitness (CRF). High-intensity interval training (HIIT) is superior to moderate-intensity continuous training (MICT) in improving CRF. The influence of training on PFC oxygenation and affects during exercise in individuals with obesity is, however, currently unknown. Twenty participants with obesity (14 males, 48 ± 8 years, body-mass index = 35 ± 6 kg·m−2) were randomised to MICT [50% peak work rate (WRpeak)] or HIIT (1-min bouts 100% WRpeak; 3 sessions/week, 8 weeks). Before/after training, participants completed an incremental ergocycle test. Near-infrared spectroscopy and the Feeling Scale assessed PFC oxygenation and affects during exercise, respectively. Improvements in CRF (e.g., WRpeak: 32 ± 14 vs 20 ± 13 W) were greater after HIIT vs MICT (p < 0.05). Only HIIT induced larger left PFC oxygenation (haemoglobin difference from 7 ± 6 to 10 ± 7 μmol) and enhanced affective valence (from 0.7 ± 2.9 to 2.2 ± 2.0; p < 0.05) at intensities ≥ second ventilatory threshold. Exercise-training induced changes in left PFC oxygenation correlated with changes in CRF [e.g., WRpeak (% predicted), r = 0.46] and post-training affective valence (r = 0.45; p < 0.05). HIIT specifically improved left PFC oxygenation and affects during exercise in individuals with obesity. Implementing HIIT in exercise programmes may therefore have relevant implications for the management of obesity, since greater affective response to exercise is thought to be associated with future commitment to physical activity.

Stubborn Exercise Responders-Where to Next?

There is a wide variance in the magnitude of physiological adaptations after resistance or endurance training. The incidence of “non” or “poor” responders to training has been reported to represent as high as 40% of the project’s sample. However, the incidence of poor responders to training can be ameliorated with manipulation of either the training frequency, intensity, type and duration. Additionally, global non-response to cardio-respiratory fitness training is eliminated when evaluating several health measures beyond just the target variables as at least one or more measure improves. More research is required to determine if altering resistance training variables results in a more favourable response in individuals with an initial poor response to resistance training. Moreover, we recommend abandoning the term “poor” responders, as ultimately the magnitude of change in cardiorespiratory fitness in response to endurance training is similar in “poor” and “high” responders if the training frequency is subsequently increased. Therefore, we propose “stubborn” responders as a more appropriate term. Future research should focus on developing viable physiological and lifestyle screening tests that identify likely stubborn responders to conventional exercise training guidelines before the individual engages with training. Exerkines, DNA damage, metabolomic responses in blood, saliva and breath, gene sequence, gene expression and epigenetics are candidate biomarkers that warrant investigation into their relationship with trainability. Crucially, viable biomarker screening tests should show good construct validity to distinguish between different exercise loads, and possess excellent sensitivity and reliability. Furthermore “red flag” tests of likely poor responders to training should be practical to assess in clinical settings and be affordable and non-invasive. Early identification of stubborn responders would enable optimization of training programs from the onset of training to maintain exercise motivation and optimize the impact on training adaptations and health.

Catheter ablation versus antiarrhythmic drugs with risk factor modification for treatment of atrial fibrillation: a protocol of a randomised controlled trial (PRAGUE-25 trial)

IntroductionAtrial fibrillation (AF), with a prevalence of 2%, is the most common cardiac arrhythmia. Catheter ablation (CA) has been documented to be superior to treatment by antiarrhythmic drugs (AADs) in...

The effect of two multi-component behavior change interventions on cognitive functions

BackgroundWe previously reported the effects of two cluster-randomized 6-month multi-component workplace interventions, targeting reducing sedentary behavior or increasing physical activity among office workers, on movement behaviors and cardiorespiratory fitness. The primary aim of this study was to investigate the effects of these interventions on cognitive functions compared to a wait-list control group. The secondary aims were to examine if changes in cognition were related to change in cardiorespiratory fitness or movement behaviors and if age, sex, or cardiorespiratory fitness moderated these associations.MethodsBoth interventions encompassed multi-components acting on the individual, environmental, and organizational levels and aimed to change physical activity patterns to improve mental health and cognitive function. Out of 263 included participants, 139 (mean age 43 years, 76% females) completed a neuropsychological test battery and wore accelerometers at baseline and 6-month follow-up. The intervention effect (aim 1) on cognitive composite scores (i.e., Executive Functions, Episodic Memory, Processing Speed, and Global Cognition) was investigated. Additionally, associations between changes in movement behaviors and cardiorespiratory fitness, and changes in cognition were examined (aim 2). Moreover, age, sex, and cardiorespiratory fitness level were investigated as possible moderators of change associations (aim 3).ResultsOverall, cognitive performance improved from baseline to follow-up, but the change did not differ between the intervention groups and the control group. Changes in cardiorespiratory fitness or any movement behavior category did not predict changes in cognitive functions. The association between changes in time in bed and changes in both Executive Function and Global Cognition were moderated by age, such that a more positive relation was seen with increasing age. A less positive association was seen between changes in sedentary behavior and Processing Speed for men vs. women, whereas higher cardiorespiratory fitness was related to a more positive association between changes in moderate-intensity physical activity and Global Cognition.ConclusionThe lack of an intervention effect on cognitive functions was expected since the intervention did not change movement behavior or fitness. Age, sex, and cardiorespiratory fitness level might moderate the relationships between movement behaviors and cognitive functions changes.Trial registrationISRCTN92968402. Registered 09/04/2018.

Mid-Life Cardiorespiratory Fitness, Obesity, and Risk of Atrial Fibrillation: The Cooper Center Longitudinal Study

BackgroundLower cardiorespiratory fitness (CRF) and higher body mass index (BMI) are associated with a higher risk of myocardial infarction and heart failure. However, the independent contribution of these lifestyle factors to the risk of atrial fibrillation (AF) is less well established. ObjectivesThe purpose of this study was to evaluation the association between midlife CRF, BMI, and risk of AF in older age. MethodsThis study included 18,493 participants without AF who underwent assessment of CRF (estimated using the maximal treadmill time) and BMI in middle age and had Medicare coverage after the age of 65 years. The association among midlife CRF, BMI, and risk of AF was assessed by fitting a proportional hazards intensity model to the failure time data with adjustment for potential confounders. The association between changes in CRF and BMI in middle age and the risk of AF was also assessed in the subset of participants with repeat CRF assessments. ResultsAmong 18,493 participants (79% men), a higher midlife BMI was significantly associated with a higher risk of AF independent of CRF levels and other potential confounders (hazard ratio per 1-kg/m2: 1.05; 95% confidence interval: 1.03-1.06). Lower midlife CRF was also associated with higher risk of AF (hazard ratio per 1 MET higher CRF: 0.98; 95% confidence interval: 0.96-0.99). However, this association was attenuated and not significant after further adjustment for BMI. Change in CRF on follow-up was also not associated with the risk of AF after adjustment for other confounders. ConclusionsThe association between low fitness and AF was primarily driven by differences in BMI. In contrast, obesity was independently associated with excess AF risk.

Change in Metabolic Syndrome and Cardiorespiratory Fitness Following Exercise Training - The Ball State Adult Fitness Longitudinal Lifestyle Study (BALL ST).

PurposeTo evaluate how the changes in directly measured cardiorespiratory fitness (CRF) relate to the changes in metabolic syndrome (MetS) status following 4–6 months of exercise training.MethodsMaximal cardiopulmonary exercise (CPX) tests and MetS risk factors were analyzed prospectively from 336 adults (46% women) aged 45.8 ± 10.9 years. MetS was defined according to the National Cholesterol Education Program-Adult Treatment Panel III criteria, as updated by the American Heart Association/National Heart, Lung, and Blood Institute (AHA/NHLBI). Pearson correlations, chi-squares, and dependent 2-tail t-tests were used to assess the relationship between the change in CRF and the change in MetS risk factors, overall number of MetS risk factors, and a MetS severity score following 4–6 months of participation in a self-referred, community-based exercise program.ResultsOverall prevalence of MetS decreased from 23% to 14% following the exercise program (P < 0.05), while CRF improved 15% (4.7 ± 8.4 mL/kg/min, P < 0.05). Following exercise training, the number of positive risk factors declined from 1.4 ± 1.3 to 1.2 ± 1.2 in the overall cohort (P < 0.05). The change in CRF was inversely related to the change in the overall number of MetS risk factors (r = −0.22; P < 0.05) and the MetS severity score (r = −0.28; p < 0.05).ConclusionThis observational cohort study indicates an inverse relationship between the change in CRF and the change in MetS severity following exercise training. These results suggest that participation in a community-based exercise program yields significant improvements in CRF, MetS risk factors, the prevalence of the binary MetS, and the MetS severity score. Improvement in CRF through exercise training should be a primary prevention strategy for MetS.

Response to Endurance Training Using Critical Speed: Influence of Genetic Background and Exercise Intensity

Exercise is used as a therapeutic option to improve an individual's quality of life or as a method to attenuate the severity of cardiovascular, respiratory, or metabolic‐related diseases. However, changes in cardiorespiratory fitness in response to endurance training are often heterogenous with individuals being more or less responsive to a similar exercise protocol. Heterogeneity in responses to exercise training is observed in humans and rodents. Low responses to training might be mitigated by modifying the standard exercise training protocol by altering the frequency, intensity, or duration of training. Threshold‐based exercise training prescription, e.g., critical speed, has also been proposed as a means to reduce the variability of training responses. The aim of this study was to identify the effect of different exercise training intensities on changes in exercise capacity in two inbred strains of mice, NZW/LacJ (NZW) and FVB/NJ (FVB). NZW mice were selected because they respond poorly to moderate intensity endurance exercise whereas, FVB mice respond well to endurance training. We hypothesized that increasing the intensity of the training would reduce the number of low or non‐responding NZW mice. To test this hypothesis, female mice from each strain were assigned to one of three treadmill training groups based on critical speed (CS): 80% of their critical speed (CS80%), 90% of their critical speed (CS90%), or sedentary controls (SED). Exercise groups within each strain were volume matched and thus ran the same distance over the 6‐week training period. Pre‐training exercise capacity differed between NZW (30.5 ± 3.5 min) and FVB (36.1 ± 2.8 min) mice (P &lt; 0.001). Critical speeds also differed between strains (NZW: 25.1 ± 2.4 m/min; FVB: 32.9 ± 1.6 m/min, P &lt; 0.001). After training, both FVB exercise groups, CS80% (10.0 ± 4.9 min, P = 0.004) and CS90% (14.0 ± 7.7 min, P = 0.007), improved their endurance capacity. In contrast, NZW CS80% did not significantly improve after training (0.4 ± 4.6 min), but NZW CS90% improved significantly (3.6 ± 2.7 min, P = 0.02). Collectively, these data indicate that the high‐responder FVB strain can adapt to moderate‐intensity and high‐intensity endurance training. The low‐responder NZW strain only showed significant improvement after sufficient homeostatic stress was induced through high‐intensity endurance training. These data suggest that increasing exercise intensity can improve responses to exercise training in low‐ or non‐responding mice.

Wheelchair-modified ergometer rowing exercise in individuals with spinal cord injury: a feasibility, acceptability, and preliminary efficacy study.

Exploratory clinical investigation. To assess the feasibility, acceptability, and preliminary efficacy of upper-body rowing exercise adapted to wheelchair users with spinal cord injury (SCI). University exercise laboratory. Eight individuals with SCI exercised on a rowing ergometer modified for wheelchair users (REMW), three times weekly, for up to 30 min per session. Participants completed feasibility and acceptability questionnaire (1-5 Likert scale), and the Wheelchair Users Shoulder Pain Index (WUSPI) before and after six weeks of exercise. Average power output (POAVG), distance rowed, percent peak heart rate (%HRpeak), and rating of perceived exertion (RPE) (6-20 scale) were monitored throughout the 18 exercise sessions and analyzed to evaluate preliminary efficacy of the exercise modality. All eight participants completed the study (97% adherence). Participants rated the exercise high on the feasibility and acceptability scale; median (interquartile range) = 5.0 (4.0-5.0), where higher numbers indicated greater feasibility. Shoulder pain was reduced by 21% yet not significantly different from baseline (p = 0.899). Physiological measures (%HRpeak = 80-83%; RPE = 15.0-16.0) indicated a high cardiovascular training load. From week 1 to week 6, POAVG and distance rowed increased by 37 and 36%, respectively (both p ≤ 0.001). Data from six weeks of exercise on the REMW suggests that upper-body rowing is a feasible and acceptable exercise modality for wheelchair users with SCI. Session data on %HRpeak, RPE, and shoulder pain indicate that REMW evoked moderate to vigorous intensity exercise without exacerbation of shoulder pain. Future research is required to quantify potential training-induced changes in cardiorespiratory fitness.

Comparison of Physical Fitness Profiles Obtained before and during COVID-19 Pandemic in Two Independent Large Samples of Children and Adolescents: DAFIS Project.

COVID-19 pandemic restrictions might have negatively affected the health-related physical fitness of children and adolescents. The aim of this study was to contrast the body composition and physical fitness data of two independent samples of children and adolescents obtained from an online database (DAFIS project) before (n = 15,287) and during (n = 2101) the first academic year of the COVID-19 pandemic. The results revealed higher values for the body mass index (p = 0.002), waist circumference (p < 0.001), and waist to hip and waist to height ratios (p < 0.001) during than before the pandemic, particularly in the case of boys. On the other hand, lower muscular fitness was observed for girls during the pandemic. Quantitative and qualitative analysis did not detect relevant changes in cardiorespiratory fitness in children or adolescents (p > 0.05). Our data suggested that pandemic constraints might have affected body composition and muscular fitness of children and adolescents. These results might be of interest for designing specific interventions oriented toward counteracting the negative effects of pandemic restrictions on health-related physical fitness.