Higher Cardiorespiratory Fitness Research Articles

Differences in Ventilatory Function Based on Cardiorespiratory Fitness and Sex.

to evaluate differences in ventilatory function, especially on breathing reserve (BR), across a wide range of cardiorespiratory fitness (CRF). we examined 198 males and 60 females who performed different spirometry tests to evaluate ventilatory function [vital capacity (VC), inspiratory capacity (IC), force vital capacity (FVC), forced expiratory volume in 1 second (FEV1), maximal voluntary ventilation (MVV)], and a ramp incremental exercise test to evaluate maximal oxygen consumption (VO2max), maximal ventilation (VEmax) and BR. Participants were classified as low, medium or high CRF based on tertile of VO2max. VC, IC, FVC, FEV1, MVV and VEmax were associated with CRF (all p < 0.008; R2 = 0.312 to 0.76). VC, IC and FVC was lower in low than medium or high CRF; FEV1 and MVV was lower in low than high CRF; and VEmax was higher as CRF increased (all p < 0.05). Contrary, BR was weakly associated with CRF (p < 0.001; R2 = 0.179), observing a lower BR only in high (p < 0.001) and medium (p = 0.022) than low CRF, and the number of individuals who depleted the BR was not different between CRF (p > 0.05). Females showed a lower VC, FVC, FEV1, MVV and VEmax than males across different relative CRF (p < 0.001). Ventilatory function is greater in individuals with a higher CRF, highlighting ventilatory function should be considered when assessing CRF. Reaching maximum possible ventilation during exercise (depleting the BR) does not seem a cause for ceasing exercise more prevalent in individuals with a high CRF, indicating that performance limitation by the respiratory system due to BR depletion is not more likely in individuals with the highest CRF. Finally, we reveal a sex difference in ventilatory function regardless CRF.

Sleep-disordered breathing and cardiometabolic and inflammatory markers in children with overweight/obesity: The role of cardiorespiratory fitness.

To investigate the association of sleep-disordered breathing (SDB) severity with cardiometabolic and inflammatory markers independently of the adiposity levels; and to explore the role of cardiorespiratory fitness in these associations in children with overweight/obesity. A total of 109 children aged 8-11 years with overweight/obesity were included in this cross-sectional study. SDB was assessed using a scale of the reduce version of the Paediatric Sleep Questionnaire. Cardiometabolic markers included fasting blood lipids biomarkers (i.e., low- and high-density lipoprotein cholesterol, and triglycerides), blood pressure, insulin, glucose, and the homeostatic model assessment index. Inflammatory markers (i.e., interleukin-6, interleukin-1β, C-reactive protein [CRP], and tumour necrosis factor alpha) were analysed. Cardiorespiratory fitness was assessed by the 20 m shuttle-run test. No significant associations were found between SDB severity and most of the cardiometabolic markers after correcting for adiposity and multiple comparisons (all p's >0.05). SDB severity was positively related to CRP (β = 0.352, p = 0.002), yet not with the remaining inflammatory markers analysed. The interaction effect of cardiorespiratory fitness presented a positive trend in the association of SDB with CRP (p = 0.1). When stratified analyses by cardiorespiratory fitness levels were conducted, a positive relation was found between SDB and CRP in the low cardiorespiratory fitness group (β = 0.465, p = 0.014), but not in the high cardiorespiratory fitness group (β = 0.236, p = 0.108). SDB severity was positively associated with CRP independently of the adiposity levels, but not with other inflammatory or cardiometabolic risk factors in children with overweight/obesity. Moreover, our results suggest that higher levels of cardiorespiratory fitness may attenuate the adverse effect of SDB severity on systematic inflammation in children with overweight/obesity.

Associations of cardiorespiratory fitness with brain white matter microstructural integrity and white matter hyperintensity volume across the adult lifespan.

Higher cardiorespiratory fitness (CRF) is associated with less deterioration in brain microstructural white matter (WM) integrity in older adults assessed with MRI diffusion tensor imaging (DTI) and brain WM hyperintensities (WMH) volume measured with fluid-attenuated-inversion-recovery (FLAIR) imaging. This study investigated associations of CRF measured with peak oxygen consumption (V̇O2peak) with brain WM microstructural integrity and WMH in healthy individuals across the adult lifespan. We hypothesized that higher CRF is associated with less deterioration in WM microstructural integrity and WMH across the adult lifespan, which in turn is associated with better cognitive performance. A total of 177 healthy adults underwent treadmill exercise testing to measure V̇O2peak, MRI scan to measure free water (FW)-corrected DTI metrics and whole-brain WMH volume, and a comprehensive cognitive test battery. Linear regression models were used to examine the associations of DTI metrics and WMH volume with age, V̇O2peak, and age × V̇O2peak interaction. Higher CRF was associated with lower FW. Age × V̇O2peak interactions were observed in FW of the corpus callosum (CC) and WMH volume, such that the positive regression slopes of FW and WMH volume with age were lower in those with higher V̇O2peak than those with lower V̇O2peak. Lower WMH volume and FW in the CC were associated with better fluid cognition composite score. In conclusion, higher CRF is associated with less deteriorations in brain WM integrity and better cognitive function across the adult lifespan. These findings highlight the importance of maintaining and improving CRF to slow brain aging.

Coronary artery calcium in athletes: friend or foe?

Regular physical activity and high cardiorespiratory fitness protect against cardiovascular disease-related morbidity and mortality and all-cause mortality in the general population. Paradoxically, recent evidence indicates that high volumes of aerobic physical activity are associated with an increased prevalence and progression of coronary artery calcium and coronary plaques in males. This review aims to synthesize current evidence concerning the relationship between aerobic physical activity and the development of coronary atherosclerosis. Evidence indicates that engaging in moderate-to-vigorous physical activity, exceeding approximately five hours or 2000 Metabolic Equivalent of Task-mins per week, is associated with increased prevalence and progression of coronary artery calcium and coronary plaques in males. This relationship appears intensity-dependent, with higher-intensity physical activity linked to greater progression of coronary artery calcium and coronary plaques. However, females seem to be less susceptible to physical activity-associated coronary atherosclerosis. Recent findings challenge the hypothesis that increased coronary artery calcification in athletes represents plaque stabilization. Athletes with elevated coronary artery calcium levels show an increased risk of cardiovascular disease outcomes and all-cause mortality compared to those without coronary artery calcium. However, their typically higher levels of cardiorespiratory fitness and physical activity, partially mitigate this risk, particularly for all-cause mortality. For optimal cardiovascular health, evidence supports maintaining physical activity volumes aligned with World Health Organization guidelines and emphasizing moderate-intensity activity (in relative terms), as this pattern appears to protect against coronary atherosclerosis development and is associated with reduced coronary artery calcium progression and lower prevalence of mixed plaques in males.

Aerobic capacity and exercise mediate protection against hepatic steatosis via enhanced bile acid metabolism.

High cardiorespiratory fitness and exercise show evidence of altering bile acid (BA) metabolism and are known to protect or treat diet-induced hepatic steatosis, respectively. Here, we tested the hypothesis that high intrinsic aerobic capacity and exercise both increase hepatic BA synthesis measured by the incorporation of 2H2O. We also leveraged mice with inducible liver-specific deletion of Cyp7a1 (LCyp7a1KO), which encodes the rate-limiting enzyme for BA synthesis, to test if exercise-induced BA synthesis is critical for exercise to reduce hepatic steatosis. The synthesis of hepatic BA, cholesterol, and de novo lipogenesis was measured in rats bred for either high (HCR) vs. low (LCR) aerobic capacity consuming acute and chronic high-fat diets. HCR rats had increased synthesis of cholesterol and certain BA species in the liver compared to LCR rats. We also found that chronic exercise with voluntary wheel running (VWR) (4 weeks) increased newly synthesized BAs of specific species in male C57BL/6J mice compared to sedentary mice. Loss of Cyp7a1 resulted in fewer new BAs and increased liver triglycerides compared to controls after a 10-week high-fat diet. Additionally, exercise via VWR for 4 weeks effectively reduced hepatic triglycerides in the high-fat diet-fed control male and female mice as expected; however, exercise in LCyp7a1KO mice did not lower liver triglycerides in either sex. These results show that aerobic capacity and exercise increase hepatic BA metabolism, which may be critical for combatting hepatic steatosis.

Exploring the Link Between Cardiovascular Fitness, Metabolic Syndrome, and Heart Rate Variability in Anesthesiology Residents at Airlangga University

Background: Cardiorespiratory fitness (CRF) is a key indicator of aerobic capacity and plays a crucial role in cardiovascular and autonomic nervous system health. Metabolic syndrome (MetS), characterized by abdominal obesity, hyperglycemia, dyslipidemia, and hypertension, increases cardiovascular disease risk and impairs autonomic function. Heart rate variability (HRV) is a noninvasive measure of autonomic balance and cardiovascular health. Objective: This review explores the interrelationship between CRF, MetS, and HRV, emphasizing its implications for anesthesiology and intensive care residents, who experience high stress and workload. Methods: A literature review was conducted to assess how CRF influences HRV and mitigates MetS-related autonomic dysfunction. Findings: Higher CRF is associated with increased HRV, indicating better autonomic regulation, while MetS is linked to reduced HRV and impaired cardiovascular function. Maintaining optimal CRF appears to counteract MetS-related autonomic imbalances, reducing cardiovascular risks in high-stress professions. Conclusion: Enhancing CRF through structured physical activity may serve as a preventive strategy against MetS-related autonomic dysfunction and cardiovascular disease, particularly for medical professionals exposed to chronic stress. Workplace interventions promoting physical fitness could play a crucial role in safeguarding the well-being of anesthesiology residents.

Exploring the 'fit for work' principle: The association between occupational physical activity, cardio-respiratory fitness, and mortality - a meta-analysis of male worker data.

This individual participant data meta-analysis investigates the association between occupational physical activity (OPA) and both cardiovascular mortality and all-cause mortality across different cardio-respiratory fitness (CRF) groups among male workers. Data were pooled from five European cohort studies. OPA was categorized into three levels and CRF into low, moderate, and high tertiles. OPA was assessed using self-reports and CRF through objective measurements. Two-stage meta-analyses were conducted. First, we analyzed each cohort using Cox-regression models then we pooled results with random effects model to evaluate the associations between OPA and both cardiovascular and all-cause mortality, stratified by CRF. Models were adjusted for age, body mass index, smoking status, leisure-time physical activity, and educational level. Among 9922 men (mean age 46.8, standard deviation 6.7, years), 55.7% died during an average 25.6-year follow-up, of which 29.3% died from cardiovascular causes. Individuals with low CRF and high levels of OPA showed increased risks of cardiovascular [hazard ratio (HR) 1.27, 95% confidence interval (CI) 1.04-1.55] and all-cause mortality (HR 1.22, 95% CI 1.07-1.40) compared to those with low CRF and low levels of OPA. High CRF mitigated cardiovascular mortality risk (HR 1.08, 95% CI 0.79-1.48) but not all-cause mortality (HR 1.27, 95% CI 0.98-1.83) for those with high OPA. Our findings for cardiovascular mortality suggest that high CRF levels may protect workers with physically demanding jobs from adverse cardiovascular outcomes, supporting the 'fit for work' principle. However, this protective effect was not observed for all-cause mortality.

The impact of cardiorespiratory fitness on Alzheimer's disease biomarkers and their relationships with cognitive decline.

Relationships between core Alzheimer's disease (AD) biomarker accumulation and cognitive decline are well-established and the literature generally suggests a favorable relationship of cardiorespiratory fitness (CRF) on AD biomarker accumulation and cognition. Differences in risk of biomarker status conversion or accumulation rates by CRF, or their potential interactive relationships with cognitive decline remain largely unknown. Participants (N=533; MeanAGE=65, 70% female) from the Wisconsin Alzheimer's Disease Research Center and the Wisconsin Registry for Alzheimer's Prevention underwent serial blood draws, and cognitive and imaging assessments (MeanFollow-up=6.0 years). PET imaging of amyloid-β (Aβ) and tau (T) and plasma phosphorylated tau-217 (pTau-217) were used to determine biomarker status (+/-). Sex-specific estimated CRF (eCRF) tertiles were created using a validated equation. Kaplan-Meier survival curves and Cox-proportional hazards models characterized the risk of becoming biomarker-positive. Linear mixed effects models estimated associations between baseline eCRF and core AD biomarker accumulation and whether eCRF modified relationships between biomarker accumulation and cognitive decline. Analyses were stratified by biomarker +/- status. No significant relationships were observed between eCRF and biomarker trajectories. However, those in the high eCRF group who were also Aβ- (HR[95%CI]=0.42[0.20, 0.88]) and pTau-217-(HR[95%CI]=0.45[0.21, 0.97]) at baseline had a significantly lower risk of becoming biomarker-positive. There was a significant attenuation of the detrimental relationship between Aβ accumulation and cognitive decline for those with high eCRF and Aβ+/T+. While CRF did not influence core AD biomarker accumulation trajectories, high CRF did seem to protect against becoming biomarker-positive and attenuate the known deleterious relationship between biomarker accumulation and cognitive decline in Aβ+/T+.

Neuroprotective mechanisms of exercise and the importance of fitness for healthy brain ageing.

Neuroprotective mechanisms of exercise and the importance of fitness for healthy brain ageing.

The Metabolic Signature of Cardiorespiratory Fitness.

High cardiorespiratory fitness (CRF) is associated with better overall health. This study aimed to find a metabolic signature associated with CRF to identify health-promoting effects. CRF based on cardiopulmonary exercise testing, targeted and untargeted metabolomics approaches based on mass spectrometry, and clinical data from two independent cohorts of the Study of Health in Pomerania (SHIP) were used. Sex-stratified linear regression models were adjusted for age, smoking, and height to relate CRF with individual metabolites. A total of 132 (SHIP-START-2: 483 men with a median age of 58 years and 450 women with a median age of 56 years) and 118 (SHIP-TREND-0: 341 men and 371 women both with a median age of 51 years) metabolites were associated with CRF. Lipids showed bidirectional relations to CRF independent of sex. Specific subsets of sphingomyelins were positively related to CRF in men (SM (OH) C14:1, SM(OH)C22:2 SM C16:0, SM C20:2 SM(OH)C24:1) and inversely in women (SM C16:1, SM C18:0, SM C18:1). Metabolites involved in energy production (citrate and succinylcarnitine) were only associated with CRF in men. In women, xenobiotics (hippurate, stachydrine) were related to CRF. The sex-specific metabolic signature of CRF is influenced by sphingomyelins, energy substrates, and xenobiotics. The greater effect estimates seen in women may emphasize the important role of CRF in maintaining metabolic health. Future research should explore how this profile changes with different types of exercise interventions or diseases in diverse populations and how these metabolites could be implemented in primary prevention settings.

Visuospatial abilities and cardiorespiratory fitness in amateur sport climbers: a cross-sectional study with healthy controls.

Previous research has suggested a potential link between specific cognitive functions, fitness, and various sports disciplines, yet the findings remain inconsistent. This study aimed to explore visuospatial functions and cardiorespiratory fitness in beginner and more advanced amateur sport climbers compared to healthy controls. This cross-sectional study used Guay's Visualization of Viewpoints task (GVV), the Ruff Figural Fluency Test (RFFT), the Corsi Block-Tapping Test (Corsi test), and the Simple Visual Reaction Time task (SVRT) to primarily assess visuospatial functions. Climbing experience (years, hardest sport climbing route completed) and cardiorespiratory fitness (VO2max via the Chester Step Test) were measured. All participants were assessed for anxiety levels using the State-Trait Anxiety Inventory prior to the cognitive function assessment. Participants (female N.=48, male N.=46, mean age 30.23±5.62) were divided into three groups: experienced climbers (N.=29), beginner climbers (N.=31), and healthy non-climbers as a control group (N.=34). There were no statistically significant differences in cognitive performance between the three groups. However, higher VO<inf>2</inf>max correlated with better performance on the GVV in the entire sample, as well as in women separately and climbers (both men and women). Additionally, among experienced climbers, GVV performance correlated with the hardest climbing route they had completed. Male climbers who climbed more frequently each week demonstrated better executive function, as indicated by generating more unique geometric patterns in the RFFT. Overall, being physically active was associated with shorter SVRT. Lastly, men significantly outperformed women on both the GVV and SVRT. Trait anxiety, which was significantly higher in women, negatively correlated with GVV scores. We found no significant differences in visuospatial performance or cardiorespiratory fitness among beginner climbers, experienced climbers, and non-climbers. However, both cardiorespiratory fitness and climbing achievements were positively associated with better visuospatial abilities. While women scored lower than men on the GVV and SVRT tests, higher cardiorespiratory fitness was linked to improved GVV performance in female participants.

Fitness and Exercise Effects on Brain Age: A Randomized Clinical Trial.

Examine the effect of aerobic exercise on structural brain age and explore potential mediators. In a single-blind, 12-month randomized clinical trial, 130 healthy participants aged 26-58 years were randomized into a moderator-to-vigorous intensity aerobic exercise group or a usual-care control group. The exercise group attended 2 supervised 60-minute sessions per week in a laboratory setting plus home-based exercise to achieve 150 minutes of exercise per week. Brain-predicted age difference (brain-PAD) and cardiorespiratory fitness (CRF) were assessed at baseline and 12 months. Intention-to-treat (ITT) and completers analyses were performed. The 130 participants (67.7% female) had a mean (SD) age of 41.28 (9.93) years. At baseline, higher CRF (VO2peak) was associated with smaller brain-PAD (β=-0.309, p=0.012). After the intervention, the exercise group showed a decrease in brain-PAD (estimated mean difference (EMD) =-0.60; 95% CI: -1.15 to -0.04; p=0.034) compared to the control group (EMD=0.35; 95% CI: -0.21 to 0.92; p=0.22); time×group interaction (between-group difference (BGD)= -0.95; 95% CI: -1.72 to -0.17; p=0.019). VO2peak improved in the exercise group (EMD=1.60; 95% CI: 0.29 to 2.90; p=0.017) compared to the control group (EMD=-0.78; 95% CI: -2.17 to 0.60; p=0.26); time×group interaction (BGD=2.38; 95% CI: 0.52 to 4.25; p=0.015). Body composition, blood pressure, and brain-derived neurotrophic factor levels were unaffected. None of the proposed pathways statistically mediated the effect of exercise on brain-PAD. The results from completers were similar. Engaging in 12 months of moderate-to-vigorous exercise reduced brain-PAD in early-to-midlife adults. The pathways by which these effects occur remain unknown.

Markers of fitness, stress, and cardiometabolic disease risk among law enforcement officers

Abstract Objective Law enforcement officers (LEOs) face numerous stressors that exacerbate cardiometabolic disease (CMD) risk. The current study examined novel and classic risk factors among a cohort of LEOs to better understand relationships between biomarkers of stress, oxidative stress, inflammation, and CMD risk. Methods Associations between measures of cardiorespiratory and muscular fitness, body composition, and cardiometabolic health with novel/classic CMD risk factors were assessed among 66 male LEOs. Results Muscular fitness and cardiorespiratory fitness were significantly associated with reduced insulin resistance. Moreover, higher fat mass and body fat percentages were significantly associated with increased markers of inflammation and insulin resistance. Conclusions Maintaining high cardiorespiratory and muscular fitness levels and improving body composition profiles can ameliorate cardiometabolic health.

Association of cardiorespiratory fitness with dementia risk across different levels of genetic predisposition: a large community-based longitudinal study

ObjectiveWe aimed to investigate the association of cardiorespiratory fitness (CRF) with cognitive function and dementia risk, taking genetic predisposition for dementia into account.MethodsWithin the UK Biobank, 61 214 dementia-free participants...

Associations of cardiorespiratory fitness with cerebral cortical thickness and gray matter volume across the adult lifespan.

High cardiorespiratory fitness (CRF) is associated with reduced cortical thinning and gray matter (GM) shrinkage in older adults. We investigated associations of CRF measured with peak oxygen consumption (V̇o2peak) with cortical thickness and GM volume across the adult lifespan. We hypothesized that higher CRF is associated with less cortical thinning and GM shrinkage across the adult lifespan, which is associated with better cognitive performance. This cross-sectional study recruited 172 sedentary yet healthy adults (65% women, 22-81 yr) who underwent treadmill exercise testing to measure V̇o2peak, structural magnetic resonance imaging to assess cortical thickness and GM volume, and a comprehensive cognitive test battery to assess fluid cognitive function. Linear regression models were used to examine the associations of total and regional cortical thickness and GM volume with age, V̇o2peak, and age × V̇o2peak interaction after adjusting for sex, education, and total intracranial volume, and the associations of cortical thickness and GM volume with fluid cognitive performance. Mean and regional cortical thickness and total GM volume were associated negatively with age, whereas no associations were observed with V̇o2peak. However, a significant interaction between age and V̇o2peak on the right superior parietal volume indicated that aging was associated with smaller right superior parietal volume in the lower CRF group, whereas no association was observed in the higher CRF group. Larger right superior parietal volume was associated with better fluid cognitive performance. These findings highlight the importance of maintaining CRF to prevent or slow brain aging from an adult lifespan perspective.NEW & NOTEWORTHY High cardiorespiratory fitness may mitigate regional gray matter shrinkage across the adult lifespan.

Cardiorespiratory Fitness and Neurophysiological Indices of Working Memory Maintenance in Young Adults.

Working memory is a crucial component of cognitive performance, supporting well-being, mental health, and successful personal and academic endeavors. Working memory performance and capacity peak during young adulthood, a critical period for managing increased life challenges. Emerging evidence indicates that cardiorespiratory fitness holds potential to enhance working memory performance; however, the underlying mechanisms remain unclear. This study examined the association between cardiorespiratory fitness and neurophysiological markers of cognitive control during a task requiring working memory maintenance. Young healthy adults (N = 112) completed a submaximal ergometer test to estimate cardiorespiratory fitness. Working memory maintenance was assessed using the Sternberg task under low and high cognitive loads, while event-related potentials (ERP) components (cue-P300, CNV, and probe-P300) were recorded. In addition, an immediate free recall task was administered. Path analysis revealed that higher cardiorespiratory fitness was significantly associated with better accuracy in the Sternberg task exclusively under high cognitive load (β = 0.21, p = 0.03). In the high load condition, higher negativity of the contingent negative variation (CNV) amplitude was significantly associated with higher fitness levels (β = -0.20, p = 0.03) and with better performance on the immediate free recall task (β = -0.23, p = 0.02), suggesting enhanced neurophysiological preparatory processes and dominance of proactive cognitive control strategy in fitter individuals. Cue-P300 and probe-P300 did not show significant associations with cardiorespiratory fitness nor working memory performance. These findings underscore the role of proactive cognitive control in mediating the benefits of cardiorespiratory fitness on cognitive performance.

Cardiorespiratory fitness is associated with cognitive function in late adulthood: baseline findings from the IGNITE study

ObjectivesTo evaluate the association between cardiorespiratory fitness (CRF) and cognition in a large sample of older adults, and to examine clinical and demographic factors that might moderate these associations.MethodsCRF was...

Physical health in young males and risk of chronic musculoskeletal, cardiovascular, and respiratory diseases by middle age: A population-based cohort study.

Cardiovascular, respiratory, and musculoskeletal disease are among the leading causes of disability in middle-aged and older people. Health and lifestyle factors in youth have known associations with cardiovascular or respiratory disease in adulthood, but largely unknown associations with musculoskeletal disease. We included approximately 40,000 18-year-old Swedish males, who completed their conscription examination in 1969 to 1970, followed up until age of 60 years. Exposures of interest were physical health: body mass and height, blood pressure, pulse at rest, muscle strength, cardiorespiratory fitness, and hematocrit; self-reported lifestyle: smoking, alcohol, and drug use; self-reported health: overall, headache and gastrointestinal. We followed the participants through the Swedish National Patient Register for incidence of common musculoskeletal (osteoarthritis, back pain, shoulder lesions, joint pain, myalgia), cardiovascular (ischemic heart disease, atrial fibrillation), and respiratory diseases (asthma, chronic obstructive pulmonary disease, bronchitis). We analyzed the associations using general estimating equations Poisson regression with all exposures included in one model and adjusted for parental education and occupation. We found that higher body mass was associated with higher risk of musculoskeletal (risk ratio [RR] per 1 standard deviation [SD] 1.12 [95% confidence interval, CI 1.09, 1.16]), cardiovascular (RR 1.22 [95% CI 1.17, 1.27] per 1 SD) and respiratory diseases (RR 1.14 [95% CI 1.05, 1.23] per 1 SD). Notably, higher muscle strength and cardiorespiratory fitness were associated with higher risk of musculoskeletal disease (RRs 1.08 [95% CI 1.05, 1.11] and 1.06 [95% CI 1.01, 1.12] per 1 SD difference in exposure), while higher cardiorespiratory fitness was protective against both cardiovascular and respiratory diseases (RRs 0.91 [95% CI 0.85, 0.98] and 0.85 [95% CI 0.73, 0.97] per 1 SD exposure, respectively). We confirmed the adverse effects of smoking, with risk ratios when comparing 11+ cigarettes per day to non-smoking of 1.14 (95% CI 1.06, 1.22) for musculoskeletal, 1.58 (95% CI 1.44, 1.74) for cardiovascular, and 1.93 (95% CI 1.60, 2.32) for respiratory diseases. Self-reported headache (category "often" compared to "never") was associated with musculoskeletal diseases (RR 1.38 [95% CI 1.21, 1.58]) and cardiovascular diseases (RR 1.29 [95% CI 1.07, 1.56]), but had an inconclusive association with respiratory diseases (RR 1.13 [95% CI 0.79, 1.60]). No large consistent associations were found for other exposures. The most notable associations with specific musculoskeletal conditions were for cardiorespiratory fitness and osteoarthritis (RR 1.23 [95% CI 1.15, 1.32] per 1 SD) and for muscle strength and back pain (RR 1.18 [95% CI 1.12, 1.24] per 1 SD) or shoulder diseases (RR 1.27 [95% CI 1.19, 1.36] per 1 SD). The main limitations include lack of adjustment for genetic factors and environmental exposures from childhood, and that the register data were available for males only. While high body mass was a risk factor for all 3 studied groups of diseases, high cardiorespiratory fitness and high muscle strength in youth were associated with increased risk of musculoskeletal disease in middle age. We speculate that these associations are mediated by chronic overload or acute trauma.

Perspective on strategies for matching across age and sex in physiology research: "recreationally active" is not good enough.

Cardiorespiratory fitness (CRF) and muscular fitness are powerful confounders in age and sex-related comparisons. This paper provides a perspective on the benefits and limitations of matching participants by physical activity behaviour, objectively measured fitness and normative fitness percentiles. Data presented herein are a subset of a larger study, and highlight that matching by physical activity, does not necessarily match on other metrics like physical fitness, especially when age-related comparisons are being made. Our data showed that young and older adults matched by physical activity behaviours showed the expected higher CRF and muscular fitness in male and younger participants, but older adults had higher CRF percentiles. This suggests that matching by physical activity behaviour may select older adults with relatively higher CRF. Researchers must choose their matching method carefully to ensure the appropriate aspects of fitness have been matched between groups. For clarity, they should also report when certain aspects of fitness have not been accounted for and give an explanation as to why.

The relationship of cardiorespiratory fitness, physical activity, and coronary artery calcification to cardiovascular disease events in CARDIA participants.

Moderate-to-vigorous-intensity physical activity (MVPA), cardiorespiratory fitness (CRF), and coronary artery calcification (CAC) are associated with cardiovascular disease (CVD) risk. While a U-shaped relationship between CRF or MVPA and CAC has been reported, the presence of CAC among highly fit individuals might be benign. We examined interactive associations of CRF or MVPA and CAC with outcomes and evaluated the relationship of CRF and MVPA to CAC incidence. CARDIA participants with CAC assessed in 2005-06 were included (n = 3,141, mean age 45). MVPA was assessed by self-report and accelerometer. CRF was estimated with a maximal graded exercise test. Adjudicated CVD events and mortality data were obtained through 2019. CAC was reassessed in 2010-11. Cox models were constructed to assess hazard ratios (HRs) for CVD, coronary heart disease (CHD), and mortality in groups defined by CAC presence/absence and lower/higher CRF or MVPA levels. Logistic models were constructed to assess associations with CAC incidence. Adjustment was made for sociodemographic and CVD risk factors. Relative to participants with no CAC and higher CRF, the adjusted HRs for CVD were 4.68 for CAC and higher CRF, 2.22 for no CAC and lower CRF, and 3.72 for CAC and lower CRF. For CHD, the respective HRs were 9.98, 2.28, and 5.52. For mortality, the HRs were 1.15, 1.58, and 3.14, respectively. Similar findings were observed when MVPA measured either by self-report or accelerometer was substituted for CRF. A robust inverse association of CRF and accelerometer-derived MVPA with CAC incidence was partly accounted for by adjusting for CVD risk factors. In middle-aged adults, CRF and MVPA demonstrated an inverse association with CAC incidence, but did not mitigate the increased cardiovascular risk associated with CAC, indicating that CAC is not benign in individuals with higher CRF or MVPA levels.