Low Cardiorespiratory Fitness Research Articles

High Intensity Interval Exercise Causes Acute Microvascular Dysfunction in Elderly Individuals with Low Cardiorespiratory Fitness - A Pilot Study

Background: Frailty is strongly associated with low physical and cardiorespiratory fitness, and unfortunately is observed in 20-50% of the ~50 million adults that experience surgical stress in the U.S. each year. The peripheral microvasculature may serve as a potential target to increase resilience to stress and improve postoperative outcomes. A better understanding of how the microvasculature responds to stress in elderly individuals with low fitness is thus needed. Objective: To define the relationship between cardiorespiratory fitness and microvascular resiliency to stress in elderly individuals. Hypothesis: Elderly individuals with low cardiorespiratory fitness will show acute reductions in acetylcholine (Ach)-mediated dilation of the skin microvasculature following the physiological stressful stimulus of high intensity interval exercise (HIIE). Methods: This was a prospective, observational study that enrolled elderly individuals aged 65-85 years from the community. Each participant was asked to complete two study visits. During visit 1, participants completed the Frailty Index and performed a graded cardiopulmonary exercise test (CPET) on a cycle ergometer with a metabolic cart to measure peak total body oxygen consumption (VO2 Peak). During visit 2, laser Doppler flowmetry with dermal microdialysis was performed on the ventral forearm to measure peak cutaneous microvascular vasodilation to Ach (10 mM). After baseline assessment, the participants performed a HIIE protocol where they repetitively switched between exercising at 70% of the peak workload achieved during the CPET for 60 seconds, followed by a 60 second active recovery at 10 watts. These intervals were repeated 12 times, for a total exercise duration of 24 min. Thirty minutes following exercise, Ach-mediated dilation of the cutaneous microvasculature was reassessed. Maximum dilator capacity of each site was assessed by infusing sodium nitroprusside (28 mM) and heating the skin to 43 °C. Results: Six individuals (1 male, 5 females; mean age 68 ±4 years) completed all study procedures. Based on age- and sex-predicted normative values for VO2 Max, three of the individuals had high physical fitness while three had low fitness (mean VO2 Peak = 27.5±1.1 vs. 13.6±3.4 ml/kg/min, respectively). Prior to HIIE there was no difference in peak dilation to Ach between the individuals with high vs. low fitness (% max dilation = 72±13 vs. 83±13, respectively). During HIIE, the individuals reached a Borg rating of perceived exertion of 15±4 (out of 20) and their peak heart rate was 74±15% of their age-predicted maximum. Ach-mediated dilation of the dermal microvasculature was reduced following HIIE in elderly individuals with low cardiorespiratory fitness (pre vs. post % maximum dilation = 82±13 vs. 49±27, respectively; mean change = -34±40 %) but unchanged in those with high fitness (pre vs. post % maximum dilation = 72±13 vs. 78±10, respectively; mean change = 5±3 %). Using Pearson correlation tests there was a strong correlation between the change in peak Ach-mediated dilation pre vs. post HIIE and both VO2 Peak (r=0.82, p=0.04) and Frailty Index score (r=-0.98, p<0.001). Conclusion: Microvascular resilience to acute stress is decreased in elderly individuals with low cardiorespiratory fitness compared to those with high fitness. None. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Mitochondrial-targeted Antioxidant Enhancing Effects on Vascular Endothelial Function in Middle-aged and Older Adults Is Influenced by Cardiorespiratory Fitness

Vascular endothelial dysfunction in middle-aged and older (MA/O, ≥ 45 y) adults is partly attributable to excess mitochondrial reactive oxygen species (mtROS) production. Aerobic exercise preserves endothelial function in preclinical models via lower mtROS and mitigates the deleterious effects of aging on cardiorespiratory fitness (CRF). However, the acute effects of a mitochondrial-targeted antioxidant on age-related vascular endothelial function in the context of CRF are currently unknown. We hypothesized lower CRF resulting from a physically inactive lifestyle contributing to age-related endothelial dysfunction is mediated via greater mtROS in humans. In a double-blind, randomized, placebo-controlled crossover study design MA/O adults were divided into two groups: exercisers (EX, n=11, age 60.0 ± 4.0 y, BMI 25.0 ± 0.9 kg/m2) and non-exercisers (NEX, n=12, age 64.0 ± 2.8 y, BMI 28.2 ± 1.0 kg/m2). CRF, assessed via VO2max, was measured on a cycle ergometer from an incremental ramp protocol (10 or 20 watts/min). Vascular endothelial function from brachial artery flow mediated dilation (FMDBA) was acquired before (pre-ingestion) and ~1 h after MitoQ (single dose, 80 mg) or placebo supplementation. A two-way repeated measures ANOVA with a Bonferroni post-hoc analysis was used to determine the effects of MitoQ and placebo on FMDBA. Compared to placebo, MitoQ increased FMDBA in NEX (pre: 4.9 ± 0.4 vs post: 7.0 ± 0.4 %, p<0.05) by +37% and brachial artery diameter (pre: 0.18 ± 0.02 vs post: 0.24 ± 0.02 mm, p<0.05) by +34% whereas no changes were observed for FMDBA (pre: 6.8 ± 0.5 vs post: 7.0 ± 0.3 %, p>0.05) or brachial artery diameter (pre: 0.25 ± 0.02 vs post: 0.26 ± 0.02 mm, p>0.05) in EX. CRF was positively correlated with baseline FMDBA (n=17, r=0.56, p=0.01) whereas the change in FMDBA with MitoQ was inversely correlated with CRF (r=-0.54, p=0.02). These data demonstrate the acute MitoQ-enhancing effects on vascular endothelial function in MA/O adults is attributable, in part, to greater mtROS in physically inactive adults with lower CRF. Funding for this study was provided, in part, by Ball State University ASPiRE internal research grant (N.A. Carlini). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Cardiorespiratory fitness is a strong and consistent predictor of morbidity and mortality among adults: an overview of meta-analyses representing over 20.9 million observations from 199 unique cohort studies

ObjectiveTo examine and summarise evidence from meta-analyses of cohort studies that evaluated the predictive associations between baseline cardiorespiratory fitness (CRF) and health outcomes among adults.DesignOverview of systematic reviews.Data sourceFive bibliographic...

Association Between Physical Activity Amount and Cardiorespiratory Fitness, Sleep Quality, and Health-Related Quality of Life in Patients With Long COVID: A Cross-sectional Study

ObjectiveTo investigate the association between physical activity (PA) amount and gender differences on cardiorespiratory fitness (CRF), sleep quality, and health-related quality of life (HRQoL) in individuals with long COVID. DesignCross-sectional study. SettingAn integrated outpatient clinic for post-COVID-19 at a medical center. ParticipantsConvenience sample of patients (N=264) diagnosed with long COVID. InterventionsNot applicable. Main Outcome MeasuresPA amounts, sleep quality, and HRQoL were measured by the International Physical Activity Questionnaire, Pittsburgh Sleep Quality Index, and the World Health Organization Questionnaire on Quality of Life: Short Form, respectively. CRF was evaluated through graded exercise testing. ResultsThe participants had a mean age of 42.5±13.5 years and a mean duration of post-COVID-19 symptoms of 12.7±6.8 weeks. More than half (n=149, 56.5%) were female patients. Female participants had significantly lower CRF than male participants (P<.05). Older age and higher body mass index were associated with worse CRF and HRQoL (P<.05). Less sitting behavior and greater amounts of vigorous-intensity PA (VPA) or total PA were associated with better CRF (P<.05). In addition, greater total PA and moderate-intensity PA (MPA) were associated with better sleep quality and HRQoL (P<.05), respectively. ConclusionsGender differences were found in CRF among patients with long COVID. Greater self-reported VPA or total PA was associated with better CRF, whereas greater total PA and MPA were associated with better sleep quality and HRQoL, respectively, in patients with long COVID. Further research is needed to explore these associations in longitudinal studies.

Low cardiorespiratory fitness is associated with elevated intraocular pressure among apparently healthy adults.

To evaluate the association of cardiorespiratory fitness with elevated intraocular pressure (IOP) in healthy adults. In this cross-sectional study, we evaluated 17,990 asymptomatic self-referred adults free of diabetes or cardiovascular disease who were screened in a preventive healthcare setting. All subjects underwent measurement of IOP and completed a maximal exercise stress test according to the Bruce protocol. Fitness was categorized into age and sex-specific quintiles according to the treadmill time and dichotomized to low (lowest quintile) and non-low fitness groups. Elevated IOP was defined as ≥ 21 mmHg. Median age was 45 (IQR 39-52) years and 12,073 (67%) were men. There were 3,351 (19%) subjects in the low fitness group. Median IOP was 14 mmHg (IQR 12-16) with elevated IOP documented in 188 (1%) subjects. Univariate binary logistic regression model demonstrated that compared with non-low fitness group, subjects in the low fitness group were 2.2 times more likely to have elevated IOP (95% CI 1.598-2.95, p<0.001). Multivariate binary logistic regression with adjustment to known cardiovascular risk factors (age, sex, hypertension, smoking, overweight, regular physical activity, low HDL cholesterol, high triglycerides, and fasting glucose levels) successfully demonstrated that lower fitness was independently and significantly associated with a 90% increased likelihood of elevated IOP (95% CI 1.37-2.61, p<0.001). Subgroup analysis revealed that the association was more pronounced among women compared with men (OR 3.8 vs. 1.6, p for interaction = 0.069). Low cardiorespiratory fitness is independently associated with increased IOP among apparently healthy adults.

Frequent sauna bathing and psychosis: Interrelationship with cardiorespiratory fitness

Frequent sauna bathing and higher cardiorespiratory fitness (CRF) levels may play a role in reducing the risk of mental disorders such as psychosis, however, data on their joint contributions is scanty. We aimed to investigate the interplay between sauna bathing, CRF and psychosis risk using a population-based prospective study. Self-reported frequency of sauna bathing (FSB) and CRF measured by respiratory gas analyses were assessed at baseline in 2221 men aged 42–61 years who had no history of psychosis. Frequency of sauna bathing was categorized as low and high (≤2 and 3–7 sessions/week, respectively) and CRF as tertiles (low, medium and high). Hazard ratios (HRs) with 95% CIs were estimated. During a median follow-up of 25.2 years, 215 psychotic disorders were recorded. Comparing high vs low FSB, the multivariable-adjusted HRs (95% CIs) for psychosis was 0.49 (0.32–0.74), which persisted on further adjustment for CRF 0.50 (0.33–0.75). Compared to low CRF, the multivariable-adjusted HRs (95% CIs) for medium and high CRF levels were 0.65 (0.46–0.90) and 0.75 (0.52–1.07) respectively. Compared to low FSB & low CRF, the HRs (95% CIs) for low FSB & medium-high CRF, high FSB & low CRF, and high FSB & medium-high CRF were 0.62 (0.45–0.84), 0.26 (0.11–0.60), and 0.41 (0.25–0.68) respectively. Frequent sauna baths and medium-high CRF levels appear to each independently decrease psychosis risk. However, frequent sauna bathing may be related to a reduced risk of psychosis irrespective of fitness levels and might be a stronger risk indicator for psychosis than CRF.

Cardiorespiratory Fitness Is Impaired in Type 1 and Type 2 Diabetes: A Systematic Review, Meta-Analysis, and Meta-Regression.

Low cardiorespiratory fitness (CRF) increases the risk of cardiovascular disease by up to eightfold and is one of the strongest predictors of mortality. Some studies demonstrate impaired CRF in people living with type 1 and type 2 diabetes compared with those without diabetes, whereas others demonstrate no diabetes-associated impairment in CRF. We aimed to determine whether diabetes can influence CRF and, if so, identify clinical associations underlying diabetes-associated exercise impairments. Sixty-eight studies were included in the quantitative analysis. Standardized mean difference (SMD) was calculated and meta-analyses and meta-regressions were performed by using a random-effects model. Diabetes is associated with a large negative effect on CRF (SMD = -0.80, P < 0.001)-an effect that is partially mitigated, but still significant, in those with high physical activity levels (SMD = -0.50, P = 0.007). A sedentary lifestyle (SMD = -0.83, P = 0.007) and the presence of clinical complications related to diabetes (SMD = -1.66, P < 0.001) predict a greater magnitude of CRF reduction in people with diabetes compared with controls without diabetes. Both type 1 diabetes and type 2 diabetes are independently associated with impaired CRF compared with controls without diabetes; however, the effect is significantly greater in those type 2 diabetes (SMD = -0.97, P < 0.001). Meta-regression analysis demonstrates the effects of diabetes on CRF are primarily associated with HbA1c levels for type 1 diabetes ( B = -0.07, P < 0.001) and body mass index for type 2 diabetes ( B = -0.17, P = 0.005). These data demonstrate a negative influence of diabetes on the key risk factor of low CRF and provide critical insight into specific clinical markers of low CRF associated with diabetes.

Cardiorespiratory fitness mediates the relationship between depressive symptomatology and cognition in older but not younger adults

Aging is commonly associated with emotional, physical, and cognitive changes, with the latter, particularly affecting executive functioning. Further, such changes may interact. For instance, depressive symptomatology is a known risk factor for developing cognitive deficits, especially at older ages. In contrast, an active lifestyle, reflected in high cardiorespiratory fitness (CRF) levels, has proven to protect against adverse effects on cognition across the adult lifespan. Hence, this study aimed to investigate the relationships between depressive symptomatology, CRF, and cognition during critical developmental stages, namely in young adults (YA), when cognitive abilities are at their peak, and in older adults (OA), when they may start to decline. Eighty-one OA with ages between 60 and 89 years (M = 70.46; SD = 7.18) and 77 YA with ages between 18 and 34 years (M = 22.54; SD = 3.72) went through (i) a sociodemographic interview, (ii) an emotional assessment, (iii) a battery of cognitive tests, and (iv) a physical evaluation assessing CRF levels, visceral fat and body-mass index. Results showed that OA exhibited lower general cognitive performance, inhibitory control, cognitive flexibility, memory, and CRF. Depressive symptoms and anxiety were not different among groups, with CRF mediating the relationship between depressive symptoms and cognition in the OA group. The present study provides valuable insights into the interplay between emotional, physical, and cognitive well-being. Additionally, it calls attention to how lifestyle factors can play a protective role against the adverse effects that depressive symptoms have on cognition, particularly at older ages.

Influence of cardiorespiratory fitness on obesity-associated inflammation in women and men: The FATCOR study

Background and aimsCardiorespiratory fitness has been postulated to lower chronic inflammation in obesity. We assessed sex-specific associations of inflammation with cardiorespiratory fitness in overweight and obese persons. Methods and resultsPeak oxygen uptake (VO2max) was measured by treadmill in 566 participants (age 48 ± 9 years, 60% women) with body mass index >27.0 kg/m2 in the FAT associated CardiOvasculaR dysfunction (FATCOR) study. Fitness was identified from age- and sex specific reference levels of VO2max. The inflammatory markers C-reactive protein (CRP), serum amyloid A (SAA), kynurenine:tryptophan ratio (KTR) and pyriodoxic acid ratio (PAr) were measured by mass spectrometry. In the total study population 63% had obesity and 74% were cardiorespiratory unfit. Unfit women had the highest fat percentage and the highest serum levels of CRP and SAA (p < 0.05). In multivariable linear regression analyses in women, higher CRP (β −0.15, p = 0.001), SAA (β −0.10, p = 0.03) and PAr (β −0.09, p = 0.03) were associated with lower VO2max after adjusting for confounders. In multivariable analyses in men, higher PAr (β −0.14, p = 0.02) was associated with lower VO2max. In multivariable analyses in obese women, higher CRP and PAr remained associated with lower VO2max (p < 0.05), while in obese men there was no significant association. When normalizing VO2max for fat-free mass (VO2maxFFM) higher CRP, SAA and PAr index were associated with lower VO2maxFFM in women, while only higher PAr index was associated with lower VO2maxFFM in men. ConclusionThe association of inflammation with lower cardiorespiratory fitness was more pronounced in women than men, in particular when obesity was present. Clinical trial registrationURL: http://www.clinicaltrials.gov NCT02805478.

Acute effects of MitoQ on vascular endothelial function are influenced by cardiorespiratory fitness and baseline FMD in middle-aged and older adults.

A key mechanism promoting vascular endothelial dysfunction is mitochondrial-derived reactive oxygen species (mtROS). Aerobic exercise preserves endothelial function in preclinical models by lowering mtROS. However, the effects of mtROS on endothelial function in exercising and non-exercising adults is limited. In a double-blind, randomized, placebo-controlled crossover study design 23 (10M/13 F, age 62.1 ± 11.5 years) middle-aged and older (MA/O, ≥45 years) adults were divided into two groups: exercisers (EX, n=11) and non-exercisers (NEX, n=12). All participants had endothelial function (brachial artery flow-mediated dilatation, FMDBA) measured before and ∼1h after mitoquinone mesylate (MitoQ) (single dose, 80mg) and placebo supplementation. A two-way repeated measures ANOVA was used to determine the effects of MitoQ and placebo on FMDBA. Pearson correlations assessed the association between the change in FMDBA with MitoQ and baseline FMDBA and cardiorespiratory fitness (CRF). Compared with placebo, MitoQ increased FMDBA in NEX by + 2.1% (MitoQ pre: 4.9 ± 0.4 vs. post: 7.0 ± 0.4 %, P=0.004, interaction) but not in EX (P=0.695, interaction). MitoQ also increased endothelial function in adults with a FMDBA <6% (P < 0.0001, interaction) but not >6% (P=0.855, interaction). Baseline FMDBA and CRF were correlated (r=0.44, P=0.037), whereas the change in FMDBA with MitoQ was inversely correlated with CRF (r=-0.66, P < 0.001) and baseline FMDBA (r=-0.73, P < 0.0001). The relationship between the change in FMDBA and baseline FMDBA remained correlated after adjusting for CRF (r=-0.55, P=0.007). These data demonstrate that MitoQ acutely improves FMDBA in NEX and EX adults who have a baseline FMDBA <6%. KEY POINTS: A key age-related change contributing to increased cardiovascular disease (CVD) risk is vascular endothelial dysfunction due to increased mitochondrial-derived reactive oxygen species (mtROS). Aerobic exercise preserves endothelial function via suppression of mtROS in preclinical models but the evidence in humans is limited. In the present study, a single dose of the mitochondria-targeted antioxidant, mitoquinone mesylate (MitoQ), increases endothelial function in non-exercisers with lower cardiorespiratory fitness (CRF) but not in exercisers with higher CRF. The acute effects of MitoQ on endothelial function in middle-aged and older adults (MA/O) are influenced by baseline endothelial function independent of CRF. These data provide initial evidence that the acute MitoQ-enhancing effects on endothelial function in MA/O adults are influenced, in part, via CRF and baseline endothelial function.

Measurement of Sedentary Behavior-The Outcomes of the Angle for Posture Estimation (APE) Method.

Hip-worn accelerometers are commonly used to assess habitual physical activity, but their accuracy in precisely measuring sedentary behavior (SB) is generally considered low. The angle for postural estimation (APE) method has shown promising accuracy in SB measurement. This method relies on the constant nature of Earth's gravity and the assumption that walking posture is typically upright. This study investigated how cardiorespiratory fitness (CRF) and body mass index (BMI) are related to APE output. A total of 3475 participants with adequate accelerometer wear time were categorized into three groups according to CRF or BMI. Participants in low CRF and high BMI groups spent more time in reclining and lying postures (APE ≥ 30°) and less time in sitting and standing postures (APE < 30°) than the other groups. Furthermore, the strongest partial Spearman correlation with CRF (r = 0.284) and BMI (r = -0.320) was observed for APE values typical for standing. The findings underscore the utility of the APE method in studying associations between SB and health outcomes. Importantly, this study emphasizes the necessity of reserving the term "sedentary behavior" for studies wherein the classification of SB is based on both intensity and posture.

Role of Cardiorespiratory Fitness and Mitochondrial Oxidative Capacity in Reduced Walk Speed of Older Adults With Diabetes.

Cardiorespiratory fitness and mitochondrial oxidative capacity are associated with reduced walking speed in older adults. The impact of cardiorespiratory fitness and mitochondrial oxidative capacity on walking speed in older adults with diabetes has not been clearly defined. We examined differences in cardiorespiratory fitness and skeletal muscle mitochondrial oxidative capacity between older adults with and without diabetes as well as determine their relative contribution to slower walking speed in older adults with diabetes. Participants with diabetes (n=159) had lower cardiorespiratory fitness and mitochondrial respiration in permeabilized fiber bundles when compared to those without diabetes (n=717), following adjustments for covariates including BMI, chronic comorbid health conditions, and physical activity. 4-m and 400-m walking speeds were slower in those with diabetes. Mitochondrial oxidative capacity alone or combined with cardiorespiratory fitness mediated ∼20-70% of the difference in walk speed between older adults with and without diabetes. Additional adjustments with BMI and co-morbidities further explained the group differences in walk speed. Cardiorespiratory fitness and skeletal muscle mitochondrial oxidative capacity contribute to slower walking speeds in older adults with diabetes.

Longitudinal development and tracking of cardiorespiratory fitness from childhood to adolescence.

Cardiorespiratory fitness (CRF) is an important indicator of health in childhood and adolescence but longitudinal studies on the development and tracking of CRF from childhood to adolescence are scarce. The objectives of this study were (1) to assess longitudinal development and track CRF over 10 years from childhood to adolescence, and (2) to examine potential sex differences in the development and tracking of CRF during this period. Participants were Icelandic children born in 1999, measured at the age of 7 (n = 190, 106 girls), 9 (n = 163, 95 girls), 15 (n = 239, 134 girls), and 17 (n = 202, 119 girls). CRF was assessed with a maximal cycle ergometer test and expressed as maximal power output (Max W) and maximal power output relative to lean mass (W/kgLM). Multilevel regression models were used to study the longitudinal development of CRF, and tracking was assessed with Spearman's rank correlation, logistic regression, and the percentage of participants remaining in low, moderate, or high CRF categories between measurements. Max W and W/kgLM increased for both boys and girls up to age 15. Max W plateaued for both boys and girls while W/kgLM plateaued for girls but declined for boys from age 15 to 17. Boys had higher Max W than girls from age 15 and higher W/kgLM from age 9. CRF tracked at low to moderate levels from childhood to adolescence and at high levels in adolescence, with higher values observed for boys than girls. Age 15 was a critical time point in the development of CRF, with values starting to plateau for girls and decline for boys. The results support early intervention for improved CRF in later years, with interventions targeting all children, regardless of their CRF level.

Cardiorespiratory fitness, physical activity, and fatigue three months after first-ever ischemic stroke

ABSTRACT Background Research on cardiorespiratory fitness (CRF) in relation to physical activity (PA) and fatigue after stroke is limited. Increased knowledge of interrelationships between these factors can help optimize rehabilitation strategies and improve health-outcomes. Objectives We aimed to: 1) evaluate CRF, PA, and fatigue, 2) characterize patients with impaired versus non-impaired CRF, and 3) examine associations of CRF with PA and fatigue, three months after first-ever ischemic stroke. Methods In this cross-sectional study CRF was measured as peak oxygen uptake (VO2peak) by cardiopulmonary exercise testing. PA was measured using accelerometers. Fatigue was assessed with the 7-item Fatigue Severity Scale (FSS). Results The sample (n=74, mean age 64±13 years, 36% women) had a mean VO2peak of 27.0±8.7 (86% of predicted). Fifty-one percent met the World Health Organization’s recommendation of ≥150 min of moderate PA/week. Mean steps-per-day was 9316±4424 (113% of predicted). Thirty-five percent of the sample had moderate-to-high fatigue (FSS≥4), mean FSS score was 3.2±1.8. Patients with impaired CRF (VO2peak<80% of predicted) had higher body-fat-percent (p<0.01), less moderate-to-vigorous PA (MVPA) (p<0.01) and a trend toward higher fatigue (p=0.053) compared to the non-impaired. Backward regression analysis showed that higher CRF was associated with more MVPA (unstandardized beta [95% CI]: 0.38 [0.15, 0.63], p=0.002) and less fatigue (unstandardized beta [95% CI]: -3.9 [-6.4, -1.6], p=0.004). Conclusions Stroke patients had lower CRF compared to reference values. Impaired CRF was mainly related to overweight. Higher CRF was associated with more MVPA and less fatigue. Exercise after stroke may be especially beneficial for patients with impaired CRF.

The joint profiles of cardiorespiratory fitness and muscle strength on daily physical activity levels in patients with symptomatic peripheral artery disease: A cross-sectional study.

In peripheral artery disease (PAD) patients, the joint profile of low strength and cardiorespiratory fitness on movement behaviors, specifically physical activity levels and sedentary time, remains unclear. To investigate the joint profiles between cardiorespiratory and neuromuscular fitness and daily physical activity among PAD patients. Cross-sectional study in a sample of 155 PAD patients. We measured their physical activity level per week using accelerometers, assessed their muscle strength through a sit-to-stand test and cardiorespiratory fitness through a six-minute walk test. Patients were categorized into three groups: those with high strength and cardiorespiratory fitness (NC, n = 28), those with at least one component classified as low (1C, n = 88), and those with both components classified as low fitness (2C, n = 39). The patients in the 1C and 2C groups spent less time engaged in low-light and moderate activities compared to the NC group (low-light: NC: 2291 ± 680 minutes/week vs. 1C: 1826 ± 649 minutes/week vs. 2C: 1885 ± 651 minutes/week, p = .005; moderate: NC: 2617 ± 796 minutes/week vs. 1C: 2071 ± 767 minutes/week vs. 2C: 2092 ± 776 minutes/week, p = .005) and the patients in the 2C group spent less time engaged in vigorous activities compared to the NC and 1C groups (NC: 155 ± 148 minutes/week vs. 1C: 110 ± 110 minutes/week vs. 2C: 64 ± 70 minutes/week, p = .003). PAD patients with low strength and/or cardiorespiratory fitness are more likely to spend less time engaging in low-light and moderate physical activities and patients with low fitness in both components are more likely to spend less time engaging in vigorous physical activity.

Adolescent Cardiorespiratory Fitness and Future Work Ability

Although research indicates that low fitness in youth is associated with a higher risk of chronic disability in men, the association of fitness in adolescence with work ability in working men and women remains unknown. To examine the associations of adolescent health-related physical fitness with future work ability. This 45-year observational cohort study, conducted in Finland, examined the direct and indirect longitudinal associations of objectively measured health-related fitness in adolescence (in 1976) with self-reported work ability and sickness absence in early middle age (in 2001) and the Work Ability Index in late middle age (in 2021). A countrywide stratified random baseline sample included fitness measurements for cardiorespiratory fitness (CRF) (running 1.5 km for girls and 2 km for boys), musculoskeletal fitness (MF; standing broad jump and sit-ups for both sexes, pull-ups for boys, and flexed-arm hang for girls), and height and weight, from which body mass index (BMI) was calculated. Structural equation modeling-based path analysis, adjusted for age and sex at baseline and for educational level, work-related physical strain, and leisure-time physical activity in late middle age, was conducted. Data analysis was performed from January to July 2023. Self-reported work ability was measured with structured questions in early middle age and with the validated Work Ability Index in late middle age. The final sample from longitudinal analyses (1207 individuals; 579 [48%] male individuals) consisted of participants with fitness measurement from age 12 to 19 years, and work ability assessment from age 37 to 44 years and/or age 57 to 64 years. Higher adolescent CRF was associated with higher work ability (839 participants; β = 0.12; 95% CI, 0.01 to 0.22; P = .03) and lower sickness absence (834 participants; β = -0.07; 95% CI, -0.12 to -0.02; P = .004) in early middle age and, indirectly, mediated by work ability in early middle age, with a higher work ability at the end of working age (603 participants; β = 0.04; 95% CI, 0.001 to 0.08; P = .04). The results remained consistent in both sexes and after adjustment for the confounders. Neither MF nor BMI was associated with work ability (MF, 1192 participants; β = -0.07; 95% CI, -0.17 to 0.03; BMI, 1207 participants, β = 0.09; 95% CI, -0.004 to 0.19) or sickness absence (MF, 1185 participants, β = 0.02; 95% CI, -0.03 to 0.06; BMI, 1202 participants, β = -0.03; 95% CI, -0.09 to 0.03) in early middle age or with late middle age work ability, mediated by work ability in early middle age (MF, 603 participants, β = -0.02; 95% CI, -0.06 to 0.01; BMI, 603 participants, β = 0.03; 95% CI, -0.004 to 0.07). These findings suggest that low CRF in youth is associated with poor work ability at the middle and end of working life, which highlights the informative and prognostic value of CRF assessment early in youth. Enhancing CRF in the first decades of life might contribute to better work capacity and productivity in the labor force, which would have implications for health, quality of life, society, and the economy.

Abstract P345: Is a Fixed Value of the Rate of Gas Exchange Appropriate to Indicate the Maximum Effort of Obese and Nonobese Adults Undergoing a Treadmill Cardiopulmonary Exercise Test?

Introduction: Obese individuals present a higher O2 uptake/workload during a treadmill cardiopulmonary exercise test (CPET) in addition to chronotropic and biomechanical impairment, which preclude them, many times, from reaching a maximal rate of gas exchange (Rmax) &gt; 1.0. Therefore, it is necessary to develop reference values for Rmax for a treadmill CPET according to age, sex, and a wide range of body mass index (BMI). Objectives: To establish reference values for Rmax for a treadmill CPET according to age, sex, and BMI. Methods: We re-examined 1,612 treadmill ramp CPETs of adults (893 women), of which 772 were obese (BMI ≥ 30 kg/m 2 ). We excluded tests of nonobese participants with HRmax &lt; 85% of predicted, of any participant with a rate of perceived exertion in the BORG scale &lt; 4 (intense), and of those that we had operational problems during the test. We produced a Rmax percentile table according to sex, age (&lt; 33, 34 to 46, and &gt; 46 years), and BMI (&lt; 30 and ≥ 30 kg/m 2 ). We fit stepwise multiple regressions to investigate the influence of age, sex, BMI, and cardiovascular risk on Rmax. We also presented an obesity-specific equation to estimate maximum heart rate (HRmax). Results: We evaluated 442 eutrophic participants (BMI &lt; 25 kg/m 2 ), 398 were overweighted (BMI = 25 - 29.99 kg/m 2 ), 295 had class 1 obesity (BMI = 30 - 34.99 kg/m 2 ), 247 had class 2 obesity (BMI = 35 - 39.99 kg/m 2 ) and 230 had class 3 obesity (BMI ≥ 40 kg/m 2 ). Age, sex, and BMI were the main determinants of Rmax (R 2 = 0.195). The table with percentiles confirmed that the lower limits of Rmax did not reach 1.0, especially in older, obese, and female participants (Table 1). In the obese participants, we could predict HRmax as 195.2 - (0.796 x age). Conclusions: The Rmax values in a treadmill CPET should be chosen considering attributes such as age, sex, and BMI. Our results suggest that fixed values of Rmax are not appropriate to indicate maximum effort, especially in people with low cardiorespiratory fitness.

Abstract P285: Relationship Between Body Mass Index, Waist Measurement, Six-Minute Walk Performance and Whole-Body Strength in Adults With Cardiovascular Disease: Findings From the Lifestyle Heart Health Study

Introduction: Cardiovascular disease (CVD) is the leading cause of death, killing 17.9 million people annually worldwide. Key risk factors include physical inactivity, overweight/obesity, high blood pressure, high cholesterol which worsen with age, and smoking and excessive alcohol intake. Six-minute walk (6MW) performance and whole-body muscle strength are both related to cardiovascular mortality and also worsen with age, particularly in the absence of physical activity. The aims of this study were to understand levels of cardiovascular risk and compliance to usual medical treatment (medication, lifestyle modifications) in a high socioeconomic Australian population, and to identify relationships between key risk factors, 6MW and muscle strength. A secondary aim was to help inform development of the Lifestyle Heart Health Education Program. Methods: This was a cross-sectional study of 473 people with CVD in Sydney. Class was classified based on the Australian socioeconomic index for areas. Conditions were defined according to Australian national guidelines. Medical history, body mass index (BMI), waist measurement, whole-body muscle strength and 6MW measurements were assessed. Simple linear and stepwise regressions were used to assess potential relationships. Results: Mean age of the cohort was 66.8±11.6; range 21-94 yrs; 68.5% female; socioeconomic index was deemed high. All participants had CVD, of which 25% were on aspirin. Hypertension was prevalent in 65% (38% on anti-hypertensives); 65% had dyslipidaemia (40% on a statin); 91% had a BMI over 26.0; and 85% of males and 80% of females had a waist measurement over gender-specific heart health recommendations. Less than 3% of the cohort smoked, and less than 10% consumed alcohol at a level deemed high-risk. Almost 20% of the cohort were at risk of CV mortality according to 6MW performance with scores less than 350 metres. Waist measurement, BMI, and blood pressure were the greatest risk factors across the cohort. Muscle strength (r=-0.34; r 2 =0.17; p&lt;0.001) and 6MW performance (r=-0.37; r 2 =0.17; p&lt;0.001) both decreased with age. BMI and age were the most significant predictors of 6MW (r=-0.45; r 2 =0.20; p=0.004) and whole-body strength (r=0.49; r 2 =0.24; p&lt;0.001) in females; waist and age were the most significant predictors of 6MW (r=-0.38; r 2 =0.14; p=0.11) and whole-body strength (r=0.41; r 2 =0.17; p=0.04) in males. Conclusion: Whilst alcohol and smoking campaigns are working to reduce consumption of these harmful substances, low cardiorespiratory and muscular fitness and overweight/obesity remain highly prevalent. Population-level interventions such as the Lifestyle Heart Health Program that aim to reduce weight and waist and improve physical activity, walking ability and muscle strength are urgently needed to reduce cardiovascular risk and mortality.

Cardiorespiratory and Muscular Fitness in Children and Adolescents with Obesity.

Examine the current state of literature related to the impact of obesity in children and adolescents on health-related physical fitness and the resultant cardiometabolic disease risk. Cardiorespiratory fitness of children and adolescents has declined over the past few decades which corresponds with an increase in obesity rates. Children with obesity are more likely to have low cardiorespiratory fitness which is associated with higher cardiometabolic disease risk and poorer mental health. The impact of obesity on muscular fitness in children and adolescents is more difficult to ascertain, but in general measures of physical function are lower in children with obesity which has also been associated with higher cardiometabolic disease risk. Components of health-related physical fitness are trending negatively in children and adolescents and appear to be related to the increase in prevalence of obesity. The resultant cardiometabolic disease risk has also risen which suggests a greater disease burden in the future. These disparaging findings highlight the need for aggressive interventions to improve physical fitness in children and adolescents.

Cardiorespiratory fitness and muscular fitness correlates in youth: A hierarchy of behavioral, contextual, and health-related outcomes

ObjectivesDespite the health importance of identifying correlates of physical fitness in youth, no investigation to date has explored the influence of behavioral, health-related, and contextual correlates simultaneously. We investigated the hierarchical relationship of multiple modifiable correlates favoring or diminishing cardiorespiratory and muscular fitness in youth. DesignCross-sectional investigation. MethodsIn a sample of 5174 children and adolescents, 31 correlates were hierarchized according to their impact on cardiorespiratory and muscular fitness assessed using the FITESCOLA® fitness battery. A Chi-squared Automatic Interaction Detection approach was employed and measures of correlation and association were used to investigate the relationship between physical fitness and correlates. ResultsIn children, body mass index was the most relevant factor to discriminate between high and low cardiorespiratory and muscular fitness of the upper, middle, and lower body. While body mass index was more important than any other correlate to differentiate levels of upper and lower body muscular fitness during adolescence, specific characteristics of sports participation emerged as key factors to discriminate between high and low cardiorespiratory fitness and middle body muscular fitness. Other correlates, including the self-report of active recess time, active commuting to school, favorable neighborhood conditions, and limited time on screens and cellphones, were demonstrative of favorable physical fitness levels. ConclusionsBoth body composition and sports-related characteristics emerged as the two most relevant factors of physical fitness in youth. Additional health benefits may be obtained from building supportive environments for sports and healthy exercise habits within the household and at different school education levels.