Physical Activity, Cardiorespiratory Fitness, and Population-Attributable Risk

Visceral adiposity index, cardiorespiratory fitness, and fasting plasma glucose associations in adolescents

BACKGROUND

The global rise in the prevalence of type 2 diabetes mellitus (T2DM) in children and adolescents is partly linked to the increasing rates of childhood obesity and physical inactivity.

AIM

To explore the independent relationships of visceral adiposity index (VAI) and cardiorespiratory fitness (CRF) with fasting plasma glucose (FPG) in adolescents.

METHODS

This descriptive cross-sectional study included 403 adolescents (202 boys and 201 girls) aged 11-19 years. Participants were evaluated for VAI, CRF, and FPG. Regression models, adjusted for age and maturity status, were used to assess the associations between VAI, CRF, and FPG.

RESULTS

The prevalence of T2DM risk was 15.3% (girls = 7.4%; boys = 7.9%). In boys, high VAI was positively associated with FPG (β = 0.190, P = 0.009), while low CRF was negatively associated with FPG (β = -0.206, P = 0.010). These associations persisted even after adjusting for CRF and VAI. However, no significant associations between VAI, CRF, and FPG were observed in girls (P > 0.05). Adolescents with high VAI and low fitness levels demonstrated poorer glycemic profiles.

CONCLUSION

Among boys, both VAI and CRF were independently associated with T2DM risk, with CRF showing a stronger association. These associations were not observed in girls. Promoting regular aerobic exercise and healthy diets may serve as essential public health promotion strategies in preventing and managing T2DM risk in adolescents.

The prognostic role of cardiopulmonary exercise testing in obesity

AIM

Poor cardiorespiratory fitness has been suggested to increase the risk of chronic diseases in obesity. We investigated the ability of key variables from cardiopulmonary exercise testing (CPET) to predict all-cause mortality in an obese cohort.

METHODS

The sample included 469 participants of both sexes (mean age 40 ± 13 years) who underwent a CPET for clinical reasons between 1 March 2009 and 1 December 2023. All-cause mortality was the prognostic endpoint. A receiver operating characteristic analysis was performed to establish optimal cut-points for CPET variables. Kaplan-Meier and Cox regression analyses were used to determine the association between CPET variables and all-cause mortality.

RESULTS

There were 46 deaths during a mean follow-up period of 69 ± 48 months, resulting in an annual mortality rate of 2%. Despite the sample being made up of mostly women (70%), there were more deaths in men (18 vs. 6%, p < 0.001).The optimal thresholds for discrimination of survival were as follows: (a) peak oxygen uptake (pVO2) ≤16 mL/kg/min; (b) minute ventilation/carbon dioxide production (VE/VCO2) slope ≥31; (c) ventilatory power ≤5.8 mmHg; and (d) circulatory power ≤2980 mmHg/mL O2/min. Kaplan-Meier survival plots revealed a significant positive association between lower pVO2, circulatory power and ventilatory power values and survival (log-rank, p < 0.001) and higher mortality for men than women. Adjusted Cox regression models showed that a pVO2 ≤16 mL/kg/min had a 20-fold higher risk of mortality when compared with >16 mL/kg/min.

CONCLUSION

Given the strong association of VO2, ventilatory efficiency, circulatory and ventilatory power with all-cause mortality, our findings support the notion that poorer cardiorespiratory fitness is associated with a poor prognosis in patients with obesity.

Using a Fitbit-based Walking Game to Improve Physical Activity Among U.S. Veterans

INTRODUCTION

Physical inactivity, hereafter inactivity, is a serious health problem among U.S. veterans, hereafter veterans. Inactive adults are at risk for adverse cardiac events and premature mortality. Specifically, among veterans, inactivity has been associated with a 23% increase in mortality. In order to increase physical activity among veterans, we developed Veterans Affairs (VA) MapTrek, a mobile-phone-based web app that allows users to take a virtual walk in interesting locations around the world while tracking their progress against that of others like themselves on an interactive map. Steps are counted by a commercially available Fitbit triaxial accelerometer, and users see their progress along a predefined scenic path overlaid on Google Maps. The objective of this study was to determine the effectiveness of VA MapTrek to increase physical activity in a population of veterans at risk for obesity-related morbidity.

MATERIALS AND METHODS

We recruited overweight and obese veterans obtaining care at the Iowa City Veterans Affairs Health Center. Half of the veterans were assigned to participate in VA MapTrek. Each week, participants were assigned virtual walking races (Monday through Saturday), which followed a predetermined route that is displayed on Google Maps. The participant's position on the map is automatically updated each time their Fitbit syncs to their phone. In addition, challenges were issued periodically. Veterans in the control group were only given a Fitbit. We regressed daily step counts on the days of the week, the days since the start of the intervention period, whether the user was in the VA MapTrek or Control group, and an interaction between the study group and the days since the start of the intervention period. We included subject-specific random intercepts and subject-specific random slopes. This model was estimated using Bayesian Hamiltonian Monte Carlo using Stan's No-U-Turns sampler. We set vague, uniform priors on all the parameters.

RESULTS

We enrolled 276 participants, but only 251 (102 in the control group and 149 in the VA MapTrek group) contributed data during the intervention period. Our analysis suggests an 86.8% likelihood that the VA MapTrek intervention led to a minimum increase of 1,000 daily steps over the 8-week period, compared to the control group. Throughout the 8-week intervention, we project that VA MapTrek participants would have taken an extra 96,627 steps, equivalent to 77.8 additional kilometers (km) (48.3 additional miles), assuming an average of 1,242 steps per km (2,000 steps per mile).

CONCLUSIONS

Our study underscores the potential of VA MapTrek as an intervention for promoting walking among veterans who face elevated risks of obesity and cardiac issues. Rural veterans are a high-risk population, and new interventions like VA MapTrek are needed to improve veterans' health.

The Potential Influence of Firearm Violence on Physical Inactivity in the United States

BACKGROUND

Despite broad recognition of the physical inactivity pandemic, little to no progress has been made in the past decade in mitigating the problem. The current analysis builds upon previous research into the drivers of physical inactivity to assess the potential interactions with firearm violence in the United States.

METHODS

We merged county-level data on firearm fatality rates, physical inactivity prevalence, the Social Vulnerability Index, and the American nations regional cultures schematic.

RESULTS

Counties with a physical inactivity prevalence currently above the federal government's 2030 goal (ie, ≥21.8%) had a significantly higher firearm fatality rate per 100,000 population. This finding was consistent for both the overall rate and race-based subgroups. The overall White, Hispanic, and Black firearm fatality rates were also significantly higher in the American nations group comprising Greater Appalachia, Deep South, El Norte, New France, and First Nation. Stepwise linear regression analysis revealed that the Social Vulnerability Index, American nations dichotomous grouping, and firearm fatality rate were all retained (P < .001) in predicting physical inactivity prevalence as a continuous variable.

CONCLUSION

In conclusion, the United States faces myriad health and societal challenges. Unhealthy lifestyles and gun violence are two of the leaders. The current analysis in conjunction with previous findings demonstrates that solving these challenges by interacting, create complexity to finding solutions that has not been thoroughly considered.

Physical activity is associated with a lower risk of contracting and dying in infection and sepsis: a Swedish population-based cohort study

BACKGROUND

Sepsis is a condition where the immune response to infection becomes dysregulated and life-threatening. It is not known whether lifestyle factors influence the risk of sepsis. The aim of the present study is to investigate the association between physical activity and the risk of acquiring and dying in infection or sepsis.

METHODS

The population-based Swedish Mammography Cohort and Cohort of Swedish Men sent participants lifestyle questionnaires in 1997 and have subsequently followed participants in national Swedish registers, including the National Patient Register, the Swedish Intensive Care Registry and the Cause of Death Register. The risk of contracting infection and sepsis, the risk of intensive care unit admission and the risk of death were estimated using multivariable Cox regression.

RESULTS

Among 64,850 cohort participants, 26,124 individuals suffered at least one episode of infection or sepsis and 4708 individuals died of infection or sepsis during the study period. In adjusted analyses, compared to exercising less than one hour per week, stated exercise one hour per week was associated with lower risk of contracting infection or sepsis, hazard ratio (HR) 0.93 (95% confidence interval (CI) 0.90-0.97), and lower risk of dying in infection or sepsis, HR 0.87 (95% CI 0.80-0.96). Further exercise was associated with even lower risk, and similar patterns were observed for walking. The population-attributable risks of contracting and dying in infection or sepsis for not exercising were 2.6% and 4.5%, respectively.

CONCLUSIONS

Exercise and walking demonstrate inverse dose-response associations with both the risk of contracting and dying in infection and sepsis, presenting possible preventative interventions for this critical condition.

Improving Reporting of Exercise Capacity Across Age Ranges Using Novel Workload Reference Equations

Exercise capacity (EC) is an important predictor of survival in the general population and in subjects with cardiopulmonary disease. Despite its relevance, considering the percent-predicted workload (%pWL) given by current equations may overestimate EC in older adults. Therefore, to improve the reporting of EC in clinical practice, our main objective was to develop workload reference equations (pWL) that better reflect the relation between workload and age. Using the Fitness Registry and the Importance of Exercise National Database (FRIEND), we analyzed a reference group of 6,966 apparently healthy participants and 1,060 participants with heart failure who underwent graded treadmill cardiopulmonary exercise testing. For the first group, the mean age was 44 years (18 to 79); 56.5% of participants were males and 15.4% had obesity. Peak oxygen consumption was 11.6 ± 3.0 METs in males and 8.5 ± 2.4 METs in females. After partition analysis, we first developed sex-specific pWL equations to allow comparisons to a healthy weight reference. For males, pWL (METs) = 14.1-0.9×10-3×age2 and 11.5-0.87×10-3×age2 for females. We used those equations as denominators of %pWL, and based on their distribution, we determined thresholds for EC classification, with average EC defined by the range corresponding to 85% to 115%pWL. Compared with %pWL using current equations, the new equations yielded better-calibrated %pWL across different age ranges. We also derived body mass index-adjusted pWL equations that better assessed EC in subjects with heart failure. In conclusion, the novel pWL equations have the potential to impact the report of EC in practice.

Genotype-Phenotype Models Predicting V̇O 2max Response to High-Intensity Interval Training in Physically Inactive Chinese

PURPOSE

This study aimed to analyze the interindividual differences of the maximal oxygen uptake (V̇O 2max ) response to 12 wk of high-intensity interval training (HIIT), and the genotype-phenotype models were constructed to predict the effect of HIIT on V̇O 2max .

METHODS

A total of 228 physically inactive adults who completed a 12-wk HIIT were analyzed. A genome-wide association study (GWAS) was conducted to identify genetic variants associated with the V̇O 2max response. Nonresponders, responders, and the highest training responders were defined as the effect sizes (ES) <0.2, ≥0.2, and ≥0.8, respectively. We generated polygenic predictor score (PPS) using lead variants and constructed a predictive model for V̇O 2max response based on a linear stepwise regression analysis.

RESULTS

The V̇O 2max increased significantly after HIIT (~14%, P < 0.001), but with interindividual differences (-7.8 to 17.9 mL·kg -1 ·min -1 ). In 27% of participants, the V̇O 2max showed no improvement. We identified one genetic locus near the γ-aminobutyric acid type A receptor subunit beta 3 gene ( GABRB3 , rs17116985) associated with V̇O 2max response at the genome-wide significance level ( P < 5 × 10 -8 ), and an additional nine single nucleotide polymorphisms (SNPs) at the suggestive significance level ( P < 1 × 10 -5 ). The SNPs rs474377, rs9365605, and rs17116985, respectively, explained 11%, 9%, and 6.2% of variance in V̇O 2max response. The 13 SNPs ( P < 1 × 10 -5 ) were found on chromosome 6 (position: 148209316-148223568). Individuals with a PPS greater than 1.757 had the highest response, and those with a PPS lower than -3.712 were nonresponders. The PPS, baseline V̇O 2max , sex, and body mass explained 56.4% of the variance in the V̇O 2max response; the major predictor was the PPS, which explained 39.4% of the variance.

CONCLUSIONS

The PPS, baseline V̇O 2max , sex, and body mass could explain the variance in V̇O 2max response. Individuals who had a PPS greater than 1.757 had the highest training response after 12 wk of HIIT. Genetic variants in a region on chromosome 6, especially the sterile alpha motif domain containing 5 gene ( SAMD5 ), which had been explored influencing angiogenesis, might have a potential role in the V̇O 2max response.

Improved cardiorespiratory fitness is associated with lower incident ischemic stroke risk: Henry Ford FIT project

BACKGROUND

Change in cardiorespiratory fitness (CRF) modulates vascular disease risk; however, it's unclear if this adds further prognostic information, particularly for ischemic stroke. The objective of this analysis is to describe the association between the change in CRF over time and subsequent incident ischemic stroke.

METHODS

This is a retrospective, longitudinal, observational cohort study of 9,646 patients (age=55±11 years; 41% women; 25% black) who completed 2 clinically indicated exercise tests (> 12 months apart) and were free of any stroke at the time of test 2. CRF was expressed as metabolic-equivalents-of-task (METs). Incident ischemic stroke was identified using ICD codes. The adjusted hazard ratio (aHR) was determined for risk of ischemic stroke associated with change in CRF.

RESULTS

Mean time between tests was 3.7 years (IQR, 2.2, 6.0). During a median of 5.0 years (IQR, 2.7, 7.6 y) of follow-up, there were 873 (9.1%) ischemic stroke events. Each 1 MET increase between tests was associated with a 9% lower ischemic stroke risk (aHR 0.91 [0.88-0.94]; n = 9.646). There was an interaction effect by baseline CRF category, but not for sex or race. A sensitivity analysis which removed those who experienced an incident diagnosis known to be associated with an increased risk of ischemic vascular disease, validated our primary findings (aHR 0.91 [0.88, 0.95]; n= 6,943).

CONCLUSIONS

Improvement in CRF over time is independently and inversely associated with a lower risk of ischemic stroke. Encouragement of regular exercise focused on improving CRF may reduce ischemic stroke risk.

The association of aerobic and muscular fitness with cognitive impairment: Findings from a nationally representative survey

This study aimed to characterize the combined association between cardiorespiratory fitness (CRF), muscular strength, and cognitive outcomes in middle-aged and older adults from low and middle-income countries (LMICs). We analyzed cross-sectional, population-based data from adults aged 50 years or older from six LMICs. Mild cognitive impairment (MCI) was defined according to the National Institute on Aging-Alzheimer's Association criteria. Estimated CRF (eCRF) was calculated using previously validated, sex-specific equations. Handgrip strength (HS) was used as an indicator of muscular strength. We used linear and robust Poisson regression models to examine the associations between eCRF, HS, and MCI. Data from 28,339 adults (63.1 [9.5] years) were analyzed. Participants with low eCRF (PR: 1.45; 95%CI: 1.11, 1.90) and HS (PR: 1.92; 95%CI: 1.79, 2.04) were more prone to have MCI. Participants with low HS showed higher likelihood of MCI than those with preserved HS through the CRF range; however, this difference was not seen among highly fit individuals (10 METs or higher). Each 1-MET (PR: 0.77; 95%CI: 0.67, 0.86) and 5-kgf (PR: 0.63; 95%CI: 0.48, 0.79) increase was associated with a reduction in the likelihood of MCI. eCRF and HS were strongly and independently associated with MCI in middle-aged and older adults.

The Effect of Wearable Activity Monitor Presence on Step Counts

Objective: In this study, we tested the effect of wearable activity monitors and tracking on physical activity over 2 weeks. Methods: Ninety young adults participated. Prior to initiation of the study, each participant was asked to download an iPhone app that tracked physical activity level (step counts) but were not told the app's purpose. Each participant was then randomly assigned to one of 3 groups (N=30/group): (1) measurement awareness, (2) measurement awareness+track/record, or (3) control. Participants in the measurement awareness and the measurement awareness+track/record groups were given a pedometer to wear for 2 weeks. Additionally, participants in the measurement awareness+track/ record group were instructed to record daily steps and submit their record after 2 weeks. Participants in the control group were not given a pedometer band nor asked track steps. Results: Neither the measurement awareness group nor the measurement awareness+track/record group were statistically different than controls during the intervention (p>.05). However, collapsing the intervention groups and comparing to the control group resulted in a 388.3 (SE=-186.9) higher daily step count during the intervention (p<.05). Conclusion: Wearable monitors modestly increases daily step count. However, the addition of recording daily step counts does not appear to provide an additional benefit in our study.

Current state of unhealthy living characteristics in White, African American and Latinx populations

The United States (US) is similar to most industrialized countries in that it falls short on many of the basic metrics related to cardiovascular and overall health. These metrics include nutritional patterns, levels of physical activity (PA), cardiorespiratory fitness (CRF), and prevalence of overweight and obesity. These issues are even more apparent in underserved communities, among whom unhealthy living characteristics cluster and contribute to a disproportionate chronic disease burden. The reasons for these inequities are complex and include social and economic factors as well as reduced access to health care. CRF has been demonstrated to be a critically important risk factor that tends to be lower in disadvantaged groups. In this article we discuss the current state of health & lifestyle characteristics in the US, the impact of social inequality on health, and the particular role that CRF and PA patterns play in the current state of unhealthy living characteristics as they relate to underserved populations.

What Comes First, the Behavior or the Condition? In the COVID-19 Era, It May Go Both Ways

Which came first, the chicken or the egg? This causality dilemma was first proposed by the Greek biographer Plutarch in the 1st century CE. While the cause-effect relationship between lifestyle behaviors and chronic disease is not always a certainty, and genetic predisposition can independently lead to premature chronic disease, the likelihood of developing one or more chronic conditions is significantly higher in those who: (1) lead sedentary lifestyles; (2) consume unhealthy diets; (3) smoke; or (4) have excess body mass. Recently, the Royal College of General Practitioners issued an apology for the title of an online event that suggested the coronavirus disease 2019 (COVID-19) is a lifestyle disease. We feel that this was the correct course of action as leading an unhealthy lifestyle is certainly not the cause for an individual contracting COVID-19 (ie, effect). However, a body of evidence has demonstrated that unhealthy lifestyle behaviors and characteristics as well as being diagnosed with one or more chronic diseases does significantly increase the risk for a complicated medical course in individuals infected with COVID-19. Moreover, the cause-effect relationship between lifestyle behaviors and characteristics and COVID-19 may eventually prove to go both ways, as the pandemic may lead to a higher prevalence of unhealthy lifestyle behaviors and characteristics over the long term that eventually leads to a higher prevalence of chronic disease. As such, health living medicine must be widely practiced and prescribed to all individuals globally.

Impact of cardiorespiratory fitness on outcomes in cardiac rehabilitation

Cardiovascular rehabilitation (CR) significantly improves outcomes in patients with cardiovascular diseases (CVD), especially coronary heart disease and heart failure (HF). Although CR is often considered as an exercise training (ET) program for patients following CVD events, CR is more than just ET as it involves education, dietary and psychological counseling, as well as a multi-factorial risk factor modification. However, a major component of ET involves efforts to measure and improve levels of cardiorespiratory fitness (CRF). In this state-of-the-art review, we analyze the data, including from our John Ochsner Heart and Vascular Institute, evaluating CRF and its impact on psychological improvements and major outcomes with CR, especially long-term survival.

Two-minute exercise testing is sufficient to estimate maximal cardiorespiratory fitness in people with epilepsy

We aimed to examine the agreement between submaximal cardiopulmonary exercise testing (CPET) measures and peak oxygen consumption (VO_2peak) in adults with epilepsy. Data from a randomized controlled trial with adults with epilepsy (N = 21) were analyzed. VO_2peak was assessed using indirect calorimetry during a treadmill graded maximal CPET. Oxygen uptake efficiency slope (OUES) was calculated from the relationship between oxygen uptake and minute ventilation during the entire test (OUES_peak) and the first 2 (OUES_2min), 3 (OUES_3min), and 4 (OUES_4min) minutes of the CPET. The strength of the association between measures was tested by Pearson correlation. Linear regression models were used to predict VO_2peak based on OUES from the different testing durations. Agreement between measured and predicted maximal values was tested using intraclass correlation coefficient (ICC) and Bland-Altman plots. OUES_2min, OUES_3min, and OUES_4min were highly associated with absolute (r = 0.84, r = 0.76, r = 0.75, respectively) and relative (r = 0.84, r = 0.78, r = 0.78, respectively) VO_2peak. Agreement (ICC = 0.83) between CPET-measured and OUES-predicted VO_2peak values was stronger with OUES_2min than the other time-based OUES markers. Bland-Altman plot showed satisfactory agreement between predicted and measured CPET measures with the narrowest limits of agreement observed with the OUES_2min. No potential bias was identified between these two measurements (p = 0.33). Changes in absolute (r = 0.77) and relative (r = 0.88) VO₂peak were highly associated with the change in OUES_2min. OUES_2min can be used as a surrogate for maximal cardiorespiratory fitness in adults with epilepsy. Studies with larger samples size are encouraged to confirm our findings in a more heterogeneous population.