Fitness versus physical activity patterns in predicting mortality in men

Fitness, independent of physical activity is associated with cerebral blood flow in adults at risk for Alzheimer's disease

Patterns of decreased resting cerebral blood flow (CBF) within the inferior temporal gyri, angular gyri, and posterior cingulate are a feature of aging and Alzheimer's disease (AD) and have shown to be predictive of cognitive decline among older adults. Fitness and physical activity are both associated with many indices of brain health and may positively influence CBF, however, the majority of research to date has examined these measures in isolation, leaving the potential independent associations unknown. The purpose of this study was to determine the unique contributions of fitness and physical activity when predicting CBF in cognitively healthy adults at risk for AD. One hundred participants (63% female) from the Wisconsin Registry for Alzheimer's Prevention underwent a maximal exercise test, physical activity monitoring, and a 3-D arterial spin labeling magnetic resonance imaging scan. For the entire sample, fitness was significantly associated with CBF while accounting for physical activity, age, gender, APOE ε4, family history of AD, education, and handedness (p = .026). Further, fitness explained significantly more variance than the combined effect of the covariates on CBF (R2 change = .059; p = .047). These results appear to be gender dependent, our data suggest fitness level, independent of physical activity, is associated with greater CBF in regions that are known to decline with age and AD for female (p = .011), but not male participants.

Prediction equation for estimating cognitive function using physical fitness parameters in older adults

Ageing is associated with declines in cognitive functions and physical fitness (PF). Physical exercise training and physical activity (PA) have been shown to have positive effects on cognitive functions and brain plasticity. This study aims to establish a practical equation for evaluating cognitive functions using PF parameters in healthy older adults. One-hundred and two older subjects were physically and clinically evaluated. Participants performed the Short Physical Performance Battery (SPPB) and handgrip test (HG); general cognitive functions were examined using the Mini Mental State Examination (MMSE). For all of them, a multiple regression analysis was used to predict MMSE from age, SPPB and HG variables. The new equation was cross validated to determine its prediction accuracy. Considering that SPPB and MMSE reference score are not different between genders, only one equation was developed for females and males. Age, SPPB and HG correlated significantly (p<0.01) with the MMSE score. The developed equation was MMSE = 19.479 + (1.548 x SPPB)-(0.130 x age) (R2 = 0.72 and root mean square errors of 3.6). The results of PF are useful for exercise specialists to achieve the best physical exercise training and PA in older adults. In conclusion, this study showed for the first time that our new equation can be used to predict subjects' cognitive functions based on SPPB results and subject age. We suggest its use when patients' cognitive functions or more appropriate clinical tests cannot be pursued.

Limitations to exercise tolerance in type 1 diabetes: the role of pulmonary oxygen uptake kinetics and priming exercise

We compared the time constant (τV̇O2) of the fundamental phase of pulmonary oxygen uptake (V̇o₂) kinetics between young adult men with type 1 diabetes and healthy control subjects. We also assessed the impact of priming exercise on τV̇O2, critical power, and muscle deoxygenation in a subset of participants with type 1 diabetes. Seventeen men with type 1 diabetes and 17 healthy male control subjects performed moderate-intensity exercise to determine τV̇O2. A subset of seven participants with type 1 diabetes performed an additional eight visits, in which critical power, τV̇O2, and muscle deoxyhemoglobin + myoglobin ([HHb+Mb], via near-infrared spectroscopy) kinetics (described by a time constant, τ_[HHb+Mb]) were determined with (PRI) and without (CON) a prior 6-min bout of heavy exercise. τV̇O2 was greater in participants with type 1 diabetes compared with control subjects (type 1 diabetes 50 ± 13 vs. control 32 ± 12 s; P < 0.001). Critical power was greater in PRI compared with CON (PRI 161 ± 25 vs. CON 149 ± 22 W; P < 0.001), whereas τV̇O2 (PRI 36 ± 15 vs. CON 50 ± 21 s; P = 0.006) and τ_[HHb+Mb] (PRI 10 ± 5 vs. CON 17 ± 11 s; P = 0.037) were reduced in PRI compared with CON. Type 1 diabetes patients showed slower pulmonary V̇o₂ kinetics compared with control subjects; priming exercise speeded V̇o₂ and [HHb + Mb] kinetics and increased critical power in a subgroup with type 1 diabetes. These data therefore represent the first characterization of the power-duration relationship in type 1 diabetes and the first experimental evidence that τV̇O2 is an independent determinant of critical power in this population.NEW & NOTEWORTHY Patients with type 1 diabetes demonstrated slower oxygen uptake (V̇o₂) kinetics compared with healthy control subjects. Furthermore, a prior bout of high-intensity exercise speeded V̇o₂ kinetics and increased critical power in people with type 1 diabetes. Prior exercise speeded muscle deoxygenation kinetics, indicating that V̇o₂ kinetics in type 1 diabetes are limited primarily by oxygen extraction and/or intracellular factors. These findings highlight the potential for interventions that decrease metabolic inertia for enhancing exercise tolerance in this condition.

Health-Related Physical Fitness Benefits in Sedentary Women Employees after an Exercise Intervention with Zumba Fitness®

Background: The protective properties of high physical fitness levels on health are manifest independently of age, sex, fatness, smoking, alcohol consumption, and other clinical factors. However, women are less active than men, which contributes to low physical fitness and a high risk of CVD. Thus, the objective of this study is to analyze the effect of two exercise interventions on health-related physical fitness in sedentary employed females. Methods: A total of 98 physically inactive adult women were randomly assigned to 3 study groups: the control group (CG) = 31, the endurance training group based on Zumba Fitness^® classes (ET; n = 39), and the concurrent training group that had an extra muscle-strengthening workout after the Zumba Fitness^® class (CnT; n = 28). Body composition (BMI, waist circumference), motor fitness (one-leg stand test), musculoskeletal fitness (shoulder–neck mobility, handgrip strength test, jump and reach test, and dynamic sit-up test), and cardiorespiratory fitness (2-km test and estimated VO₂ max) were assessed with the ALPHA-Fit test battery for adults. Results: Both interventions showed a significant improvement in the majority of health-related fitness and body composition variables/test (waist circumference: ET = −2.275 ± 0.95, p = 0.02, CnT = −2.550 ± 1.13, p = 0.03; one-stand leg test: ET = 13.532 ± 2.65, p < 0.001; CnT = 11.656 ± 2.88, p < 0.001; shoulder–neck mobility: ET = 1.757 ± 0.44, p < 0.001, CnT = 2.123 ± 0.47, p < 0.001; handgrip test: 0.274 ± 0.08, p < 0.001, CnT = 0.352 ± 0.08, p < 0.001; dynamic sit-up: ET = 1.769 ± 0.45, p < 0.001, CnT = −1.836 ± 0.49, p < 0.001; 2-km test time: −1.280 ± 0.25, p < 0.001, CnT = −1.808 ± 0.28, p < 0.001; estimated VO₂ max: ET = 1.306 ± 0.13, p < 0.001, CnT = 1.191 ± 0.15, p < 0.001). There were no significant differences after the intervention between the two exercise intervention groups. Conclusions: Exercise interventions based on Zumba fitness^® or Zumba fitness^® combined with an extra muscle-strengthening workout based on bodyweight training exercises are effective strategies to improve the health-related physical fitness in sedentary women employees.

The effects of endurance exercise on the heart: panacea or poison?

Regular aerobic physical exercise of moderate intensity is undeniably associated with improved health and increased longevity, with some studies suggesting that more is better. Endurance athletes exceed the usual recommendations for exercise by 15-fold to 20-fold. The need to sustain a large cardiac output for prolonged periods is associated with a 10-20% increase in left and right ventricular size and a substantial increase in left ventricular mass. A large proportion of endurance athletes have raised levels of cardiac biomarkers (troponins and B-type natriuretic peptide) and cardiac dysfunction for 24-48 h after events, but what is the relevance of these findings? In the longer term, some endurance athletes have an increased prevalence of coronary artery disease, myocardial fibrosis and arrhythmias. The inherent association between these 'maladaptations' and sudden cardiac death in the general population raises the question of whether endurance exercise could be detrimental for some individuals. However, despite speculation that these abnormalities confer an increased risk of future adverse events, elite endurance athletes have an increased life expectancy compared with the general population.

An Overview of the Beneficial Effects of Exercise on Health and Performance

Life expectancy is steadily increasing in modern societies, and so are noncommunicable diseases such as cardiovascular diseases, diabetes, obesity, and cancer, accounting for more than 70% of all deaths globally. The costs associated with these diseases are enormous, but it has been estimated that the majority of these noncommunicable diseases are preventable. In addition to an unhealthy diet, tobacco use, and harmful use of alcohol, physical inactivity is a key risk factor. Consequently, physical activity is a logical remedy, and in this chapter an overview of the numerous beneficial effects of physical activity on health and performance is given.The chapter is divided into three parts: First, the basics of physical activity and exercise are discussed, for instance exercise classification, exercise intensity operationalization, energy supply, and the acute effects of exercise such as blood flow redistribution and increased cardiac output. In the second part, the effects of exercise on physical performance are summarized. Specifically, it is discussed how endurance, strength, power, and balance can be improved. This discussion includes recommendations regarding the type, intensity, and duration of the exercise leading to improvements in one of these aspects of physical performance, as well as the mechanisms causing these adaptations. In the third part, the beneficial effects of physical activity on physical and mental health are outlined, with particular attention to cardiovascular diseases, the metabolic syndrome, musculoskeletal diseases, mood, anxiety, depression, and dementia.It can be concluded that with adequate programming, regular physical activity is an effective way to improve physical performance, improve physical and mental health, and reduce the risk factors for many noncommunicable diseases such as cardiovascular diseases, metabolic syndrome, sarcopenia, osteoporosis, and depression. In contrast to medication, physical exercise has no negative side effects, costs very little, and targets many health issues at once. If the multitude of beneficial effects of regular exercise were to be combined in a single low-cost drug, it would be prescribed for almost all types of physical and mental health issues.

Exercise and Stroke

Stroke is a leading cause of mortality and morbidity all around the world. Identification of stroke risk factors and protective lifestyles is necessary for optimizing personalized treatment and reducing mortality. Sedentary lifestyle is a well-known modifiable risk factor in primary and secondary stroke prevention. Also, in recent years, exercise has been described as a neuroprotective and neuroreparative factor. Here we summarized the existing available evidence of the relationship between physical activity and stroke.

Striated muscle-specific serine/threonine-protein kinase beta segregates with high versus low responsiveness to endurance exercise training

Bidirectional selection for either high or low responsiveness to endurance running has created divergent rat phenotypes of high-response trainers (HRT) and low-response trainers (LRT). We conducted proteome profiling of HRT and LRT gastrocnemius of 10 female rats (body weight 279 ± 35 g; n = 5 LRT and n = 5 HRT) from generation 8 of selection. Differential analysis of soluble proteins from gastrocnemius was conducted by label-free quantitation. Genetic association studies were conducted in 384 Russian international-level athletes (age 23.8 ± 3.4 yr; 202 men and 182 women) stratified to endurance or power disciplines. Proteomic analysis encompassed 1,024 proteins, 76 of which exhibited statistically significant (P < 0.05, false discovery rate <1%) differences between HRT and LRT muscle. There was significant enrichment of enzymes involved in glycolysis/gluconeogenesis in LRT muscle but no enrichment of gene ontology phrases in HRT muscle. Striated muscle-specific serine/threonine-protein kinase-beta (SPEG-β) exhibited the greatest difference in abundance and was 2.64-fold greater (P = 0.0014) in HRT muscle. Coimmunoprecipitation identified 24 potential binding partners of SPEG-β in HRT muscle. The frequency of the G variant of the rs7564856 polymorphism that increases SPEG gene expression was significantly greater (32.9 vs. 23.8%; OR = 1.6, P = 0.009) in international-level endurance athletes (n = 258) compared with power athletes (n = 126) and was significantly associated (β = 8.345, P = 0.0048) with a greater proportion of slow-twitch fibers in vastus lateralis of female endurance athletes. Coimmunoprecipitation of SPEG-β in HRT muscle discovered putative interacting proteins that link with previously reported differences in transforming growth factor-β signaling in exercised muscle.

Cardiorespiratory Fitness, Smoking Status, and Risk of Incidence and Mortality From Cancer: Findings From the Veterans Exercise Testing Study

BACKGROUND

To assess the joint and stratified associations between cardiorespiratory fitness (CRF), incidence, and mortality from cancer in never, former, and current male smokers.

METHODS

CRF (treadmill exercise test) was assessed in 4694 men (never smokers [n = 1715]; former smokers [n = 1602], 32.4 [30.5] pack-years; and current smokers [n = 1377], 40.3 [26] pack-years) aged 58.1 (17.3) years, and prospectively followed for 12.7 (7.5) years. Multivariable Cox hazard models were analyzed.

RESULTS

In joint analyses, where high CRF in never smokers was used as a reference, hazard ratios and 95% (confidence intervals) for cancer incidence and cancer mortality were as follows: moderate CRF 1.41 (1.0-1.9) and 3.0 (1.7-5.5) in never smokers, 1.65 (1.3-2.2) and 3.7 (2.1-6.6) in former smokers, and 1.3 (0.9-1.7) and 3.4 (1.9-6.1) in current smokers, respectively. The corresponding values for low CRF were 1.53 (1.1-2.2) and 5.1 (2.7-9.5), 1.84 (1.3-2.5) and 6.6 (3.7-11.8), and 1.5 (1.1-2.2) and 5 (2.7-9.3), respectively. In stratified analyses by smoking status, compared with low CRF, moderate and high CRF were associated with a 32% to 78% reduction in cancer mortality risk (P trend for all <.001).

CONCLUSION

Higher CRF is associated with lower risk of incidence and mortality from cancer regardless of smoking status, supporting the potential preventive benefits for public health.

Cardiorespiratory fitness and future risk of venous thromboembolism

BACKGROUND

Cardiorespiratory fitness (CRF) is a strong predictor of future arterial cardiovascular disease and premature mortality. However, there are limited data on the association between CRF and the risk of incident venous thromboembolism (VTE).

OBJECTIVES

To investigate whether estimated CRF (eCRF) was associated with the risk of incident VTE in a cohort recruited from the general population.

METHODS

Participants (n = 10 393) from the sixth survey of the Tromsø Study (2007-08) were included, and incident VTEs were recorded up to 31 December 2016. CRF was estimated in sex-specific algorithms based on age, waist circumference, resting heart rate, and self-reported physical activity. Hazard ratios (HRs) with 95% confidence intervals (CIs) of VTE according to categories of eCRF were estimated in Cox regression models adjusted for sex with age as timescale. The impact of weight status was evaluated in analyses stratified by weight category.

RESULTS

There were 176 incident VTEs during follow-up. Compared with individuals with eCRF < 85% of age-predicted, those with eCRF of 85% to 100% and >100% of age-predicted had 46% (HR 0.54; 95% CI 0.39-0.77) and 67% (HR 0.33; 95% CI 0.20-0.54) lower VTE risk, respectively. Compared with overweight/obese individuals with eCRF < 85% of age-predicted, overweight/obese individuals with eCRF ≥ 85% had 50% (HR 0.50, 95% CI 0.35-0.74) lower risk, and normal weight individuals with eCRF ≥ 85% had 55% (HR 0.45, 95% CI 0.30-0.68) lower risk.

CONCLUSIONS

Higher eCRF was associated with lower risk of incident VTE. The association was independent of weight categories, suggesting that higher eCRF may modify the association between obesity and VTE.

Cardiorespiratory Fitness and Mortality in Healthy Men and Women

BACKGROUND

There is a well-established inverse relationship between cardiorespiratory fitness (CRF) and mortality. However, this relationship has almost exclusively been studied using estimated CRF.

OBJECTIVES

This study aimed to assess the association of directly measured CRF, obtained using cardiopulmonary exercise (CPX) testing with all-cause, cardiovascular disease (CVD), and cancer mortality in apparently healthy men and women.

METHODS

Participants included 4,137 self-referred apparently healthy adults (2,326 men, 1,811 women; mean age: 42.8 ± 12.2 years) who underwent CPX testing to determine baseline CRF. Participants were followed for 24.2 ± 11.7 years (1.1 to 49.3 years) for mortality. Cox-proportional hazard models were performed to determine the relationship of CRF (ml·kg^-1·min^-1) and CRF level (low, moderate, and high) with mortality outcomes.

RESULTS

During follow-up, 727 participants died (524 men, 203 women). CPX-derived CRF was inversely related to all-cause, CVD, and cancer mortality. Low CRF was associated with higher risk for all-cause (hazard ratio [HR]: 1.73; 95% confidence interval [CI]: 1.20 to 3.50), CVD (HR: 2.27; 95% CI: 1.20 to 3.49), and cancer (HR: 2.07; 95% CI: 1.18 to 3.36) mortality compared with high CRF. Further, each metabolic equivalent increment increase in CRF was associated with a 11.6%, 16.1%, and 14.0% reductions in all-cause, CVD, and cancer mortality, respectively.

CONCLUSIONS

Given the prognostic ability of CPX-derived CRF for all-cause and disease-specific mortality outcomes, its use should be highly considered for apparently healthy populations as it may help to improve the efficacy of the individualized patient risk assessment and guide clinical decisions.

Associations of vigorous physical activity with all-cause, cardiovascular and cancer mortality among 64 913 adults

Background

Physical activity recommendations state that for the same energy expenditure, moderate-to-vigorous physical activities (MVPAs) produce similar health benefits. However, few epidemiological studies have tested this hypothesis.

Design

We examined whether, compared with moderate, vigorous activity was associated with larger mortality risk reductions.

Methods

Data from 11 cohorts of the Health Survey for England and the Scottish Health Survey, collected from 1994 to 2011 (mean (SD) follow-up, 9.0 (3.6) years). Adults aged ≥30 years reported MVPA and linkage to mortality records. Exposure was the proportion of self-reported weighted MVPA through vigorous activity. Outcomes were all-cause, cardiovascular disease (CVD) and cancer mortality.

Results

Among 64 913 adult respondents (44% men, 56% women, mean (SD) age, 49.8 (13.6) years), there were 5064 deaths from all-causes, 1393 from CVD and 1602 from cancer during 435 743 person-years of follow-up. Compared with those who reported no vigorous physical activity, and holding constant the volume of weighted MVPA, vigorous activity was associated with additional reductions in mortality risk. For all-cause mortality, the adjusted HR was HR=0.84 (95% CI 0.71, 0.99) and HR=0.84 (95% CI 0.76, 0.94) among those who reported between >0% and<30%, or ≥30% of their activity as vigorous, respectively. For CVD and cancer mortality, point estimates showed similar beneficial associations yet CIs were wider and crossed unity.

Conclusion

Vigorous activities were associated with larger reductions in mortality risk than activities of moderate intensity, but no evidence of dose–response effects was found.

Running effects on cognition and plasticity (ReCaP): study protocol of a longitudinal examination of multimodal adaptations of marathon running

Regular moderate physical activity (PA) has been linked to beneficial adaptations in various somatic diseases (e.g. cancer, endocrinological disorders) and a reduction in all-cause mortality from several cardiovascular and neuropsychiatric diseases. This study was designed to investigate acute and prolonged exercise-induced cardio- and neurophysiological responses in endurance runners competing in the Munich Marathon. ReCaP (Running effects on Cognition and Plasticity) is a multimodal and longitudinal experimental study. This study included 100 participants (20-60 years). Six laboratory visits were included during the 3-month period before and the 3-month period after the Munich marathon. The multimodal assessment included laboratory measurements, cardiac and cranial imaging (MRI scans, ultrasound/echocardiography) and neurophysiological methods (EEG and TMS/tDCS), and vessel-analysis (e.g. retinal vessels and wave-reflection analyses) and neurocognitive measurements. The ReCaP study was designed to examine novel exercise-induced cardio- and neurophysiological responses to marathon running at the behavioral, functional and morphological levels. This study will expand our understanding of exercise-induced adaptations and will lead to more individually tailored therapeutic options.

Association of Fitness With Racial Differences in Chronic Kidney Disease

INTRODUCTION

Non-white minorities are at higher risk for chronic kidney disease than non-Hispanic whites. Better cardiorespiratory fitness is associated with slower declines in estimated glomerular filtration rate and a lower incidence of chronic kidney disease. Little is known regarding associations of fitness with racial disparities in chronic kidney disease.

METHODS

A prospective cohort of 3,842 young adults without chronic kidney disease completed a maximal treadmill test at baseline in 1985-1986. Chronic kidney disease status was defined as estimated glomerular filtration rate of <60 mL/min/1.73 m² during 10-, 15-, 20-, 25-, and 30-year follow-up assessments (through 2006). Analyses were completed in 2019. Multivariable Cox models were used to determine hazard ratios and 95% CI for incidence of chronic kidney disease. Multivariable models included race, gender, age, field center, education, baseline estimated glomerular filtration rate, and time-varying covariates of healthy diet index, smoking status, alcohol intake, BMI, systolic blood pressure, and fasting glucose. Percent attenuation quantified the association of fitness to racial disparities in chronic kidney disease.

RESULTS

Chronic kidney disease incidence was higher among blacks (n=83/1,941, 1.61 per 1,000 person years) than whites (43/1,901, 0.82 per 1,000 person years). Every 1-minute shorter treadmill duration was associated with 1.14 (95% CI=1.04, 1.25) times higher risk of chronic kidney disease. Blacks were 1.72 (95% CI=1.13, 2.63) times more likely to develop chronic kidney disease compared with whites. The risk was reduced to 1.54 (95% CI=1.01, 2.39) with fitness added. This suggests that fitness is associated with 20.4% (95% CI=5.8, 43.0%) of the excess risk of chronic kidney disease attributable to race.

CONCLUSIONS

Low fitness is a modifiable factor that may contribute to the racial disparity in chronic kidney disease.

The Association of Cardiorespiratory Fitness on Memory Function: Systematic Review

Background and Objectives: Cardiorespiratory fitness is an important predictor of cardiovascular and cardiometabolic health. To extend our knowledge on the health effects associated with cardiorespiratory fitness, the objective of this study was to evaluate the association of cardiorespiratory fitness on memory function. Materials and Methods: Embase/PubMed, Web of Science, Google Scholar, Sports Discus, and PsychInfo databases were searched. Inclusionary criteria included: (1) were conducted among adult humans (18+ years), (2) evaluated cardiorespiratory fitness as the independent variable, (3) measured cardiorespiratory fitness with an objective device (e.g., indirect calorimetry), (4) evaluated memory function (any type) as the outcome measure, and (5) included either a cross-sectional, prospective, or experimental-study design. Information on the participant’s characteristics, study design, cardiorespiratory fitness assessment, memory type, whether the study statistically controlled for exercise behavior, and study results were extracted. The relationship between cardiorespiratory fitness and memory was synthesized while considering the data extraction parameters. Results: In total, 17 articles met the inclusionary criteria, including two prospective cohort studies and 15 cross-sectional studies. The main findings of this review are twofold: (1) across the 17 evaluated studies, 15 (88.2%) studies demonstrated some evidence of a positive association between cardiorespiratory fitness (CRF) and memory function, and (2) none of these 17 studies statistically controlled for physical activity behavior. Conclusion: CRF appears to be positively associated with memory function, however, it is uncertain as to whether this association occurs independently of physical activity or is mediated via physical activity behavior.

PCI Alternative Using Sustained Exercise (PAUSE): Rationale and trial design

Cardiovascular disease (CVD) currently claims nearly one million lives yearly in the US, accounting for nearly 40% of all deaths. Coronary artery disease (CAD) accounts for the largest number of these deaths. While efforts aimed at treating CAD in recent decades have concentrated on surgical and catheter-based interventions, limited resources have been directed toward prevention and rehabilitation. CAD is commonly treated using percutaneous coronary intervention (PCI), and this treatment has increased exponentially since its adoption over three decades ago. Recent questions have been raised regarding the cost-effectiveness of PCI, the extent to which PCI is overused, and whether selected patients may benefit from optimal medical therapy in lieu of PCI. One alternative therapy that has been shown to improve outcomes in CAD is exercise therapy; exercise programs have been shown to have numerous physiological benefits, and a growing number of studies have demonstrated reductions in mortality. Given the high volume of PCI, its high cost, its lack of effect on survival and the potential for alternative treatments including exercise, the current study is termed "PCI Alternative Using Sustained Exercise" (PAUSE). The primary aim of PAUSE is to determine whether patients randomized to exercise and lifestyle intervention have greater improvement in coronary function and anatomy compared to those randomized to PCI. Coronary function and anatomy is determined using positron emission tomography combined with computed tomographic angiography (PET/CTA). Our objective is to demonstrate the utility of a non-invasive technology to document the efficacy of exercise as an alternative treatment strategy to PCI.

"With Every Step, We Grow Stronger": The Cardiometabolic Benefits of an Indigenous-Led and Community-Based Healthy Lifestyle Intervention

Community-based and Indigenous-led health and wellness approaches have been widely advocated for Indigenous peoples. However, remarkably few Indigenous designed and led interventions exist within the field. The purpose of this study was to evaluate an Indigenous-led and community-based health and wellness intervention in a remote and rural Indigenous community. This protocol was designed by and for Indigenous peoples based on the aspirations of the community (established through sharing circles). A total of 15 participants completed a 13-week walking and healthy lifestyle counselling program (incorporating motivational interviewing) to enhance cardiometabolic health. Measures of moderate-to-vigorous physical activity (MVPA; 7-day accelerometry and self-report), predicted maximal aerobic power (VO₂max; 6-min walk test), resting heart rate and blood pressure, and other health-related physical fitness measures (musculoskeletal fitness and body composition) were taken before and after the intervention. The intervention led to significant (p < 0.05) improvements in VO₂max (7.1 ± 6.3 % change), with the greatest improvements observed among individuals with lower baseline VO₂max (p < 0.05, r = -0.76). Resting heart rate, resting systolic blood pressure, and resting diastolic blood pressure decreased significantly (p < 0.05) after the intervention. Self-reported and accelerometry-measured frequency of MVPA increased significantly (p < 0.05), and the total MVPA minutes (~275 min/week) were above international recommendations. Change in VO₂max was significantly correlated with change in self-reported (r = 0.42) and accelerometry-measured (r = 0.24) MVPA minutes. No significant changes were observed in weight, body mass index, waist circumference, body fat (via bioelectrical impedance), grip strength, and flexibility. These findings demonstrate that a culturally relevant and safe, community-based, Indigenous-led, health and wellness intervention can lead to significant and clinically relevant improvements in cardiometabolic health and physical activity behaviour, with the greatest changes being observed in the least active/fit individuals.

Non-alcoholic fatty liver disease: Prevalence and all-cause mortality according to sedentary behaviour and cardiorespiratory fitness. The HUNT Study

PURPOSE

Sedentary behaviour (SB) and low physical activity (PA) are independently associated with non-alcoholic fatty liver disease (NAFLD). Compared to PA, high cardiorespiratory fitness (CRF) has been associated with a higher protection against all-cause mortality and a number of specific diseases. However, this relationship has not been investigated in NAFLD. This study examined the roles of SB and CRF on: i) the likelihood of having NAFLD in the general population, and ii) the risk of mortality over 9 years within individuals having NAFLD.

METHODS

A cross-sectional analysis of 15,781 adults (52% female; age range 19-95 years) was conducted. Self-reported SB was divided into tertiles. CRF was estimated using validated non-exercise models, and the presence of NAFLD from the Fatty Liver Index. Adjusted Odds Ratios and 95% Confidence Intervals for NAFLD were estimated using logistic regression analyses. Hazard Ratios for all-cause mortality were estimated using Cox proportional hazard regression in individuals with NAFLD.

RESULTS

For each additional 1 h/d of SB, the likelihood of having NAFLD was significantly increased by 4% (CI, 3-6%). In combined analyses, compared with the reference group [high CRF and low (≤4 h/d) SB], individuals with low CRF had a markedly higher likelihood of having NAFLD (OR, 16.9; CI 12.9-22.3), even if they had SB ≤ 4 h/d. High CRF attenuated the negative role of SB up to 7 h/d on NAFLD. Over 9.4 ± 1.3 years of follow-up, individuals with NAFLD and low CRF had the risk of mortality increased by 52% (CI, 10-106%) compared to those with high CRF, regardless of SB or meeting PA guidelines.

CONCLUSIONS

Low CRF increases the risk of premature death in individuals with NAFLD, and is strongly associated with higher likelihood of having NAFLD, outweighing the influence of SB.

Association of cardiorespiratory fitness on interhemispheric hippocampal and parahippocampal functional connectivity

Interhemispheric functional connectivity is associated with cognitive functioning. Although previous work has evaluated the association of cardiorespiratory fitness on cognitive function, there has been a limited investigation of the association of cardiorespiratory fitness on the functional connectivity of memory-related brain structures. As such, the objective of this study was to examine the association between cardiorespiratory fitness and parahippocampal and hippocampal interhemispheric functional connectivity. Data from the Nathan Kline Institute-Rockland Sample (NKI-RS) were utilized. Our analysis consisted of 284 participants (M_age  = 43 years; 62% female). Cardiorespiratory fitness was objectively measured using a cycle ergometer protocol. Parahippocampal and hippocampal interhemispheric functional connectivity were assessed from fMRI. Higher cardiorespiratory fitness was associated with greater parahippocampal (β = 0.004; CI, 0.00009 to 0.008, p = 0.04), but not hippocampal (β = 0.001; CI, -0.002 to 0.005, p = 0.44) interhemispheric functional connectivity. In conclusion, enhanced cardiorespiratory fitness may facilitate parahippocampal interhemispheric functional connectivity.

Cardiorespiratory fitness and cardiovascular disease - The past, present, and future

The importance of cardiorespiratory fitness (CRF) is now well established and it is increasingly being recognized as an essential variable which should be assessed in health screenings. The key findings that have established the clinical significance of CRF are reviewed in this report, along with an overview of the current relevance of exercise as a form of medicine that can provide a number of positive health outcomes, including increasing CRF. Current assessment options for assessing CRF are also reviewed, including the direct measurement via cardiopulmonary exercise testing which now can be interpreted with age and sex-specific reference values. Future directions for the use of CRF and related measures are presented.

Aerobic Training Associated with Arginine Supplementation Reduces Collagen-Induced Platelet Hyperaggregability in Rats under High Risk to Develop Metabolic Syndrome

BACKGROUND

Increased platelet response is seen in individuals with metabolic syndrome. Previous reports have shown that arginine supplementation and aerobic exercise training enhance vascular nitric oxide (NO) activity and inhibit platelet hyperaggregability; however, the effects of their association remain unknown.

AIM

To investigate whether arginine supplementation and aerobic exercise association may exert beneficial effects, reducing platelet hyperaggregability in rats under high risk to develop metabolic syndrome.

METHODS

Wistar rats were divided into two groups: control (C) and fructose (F - water with 10% of fructose). After two weeks, the F group was subdivided into four groups: F, the same as before; fructose + arginine (FA - 880 mg/kg/day of L-arginine by gavage); fructose + training (FT); and fructose + arginine + training (FTA). Treatment lasted for eight weeks.

RESULTS

The fructose administration was able to increase the collagen-induced platelet aggregation (27.4 ± 2.7%) when compared to the C group (8.0 ± 3.4%). Although the arginine supplementation (32.2 ± 6.3%) or aerobic training (23.8 ± 6.5%) did not promote any change in platelet collagen-induced hyperaggregability, the association of arginine supplementation and aerobic exercise promoted an inhibition of the platelet hyperaggregability induced by fructose administration (13.9 ± 4.4%) (P < 0.05). These effects were not observed when ADP was employed as an agonist. In addition, arginine supplementation associated with aerobic exercise promoted a decrease in interleukin-6 (IL-6) and interleukin-8 (IL-8) serum levels when compared to the fructose group, demonstrating an anti-inflammatory effect.

CONCLUSIONS

Our data indicate an important role of arginine supplementation associated with aerobic exercise, reducing platelet hyperaggregability and inflammatory biomarker levels in rats under high risk to develop metabolic syndrome.

Risk Factors Associated with Poor Physical Fitness in Three- to Six-Year-Old Children in Tujia-Nationality Settlement of China

Background

Physical fitness has been recognized not only as an integrated predictor of the body's functional status, but also as an important marker of health outcomes. The aim of this study was to examine the factors associated with physical fitness among 3-6-year-old children within the Tujia-Nationality settlement in the years 2005, 2010, and 2014.

Methods

Demographics questionnaires and fitness assessment were performed to identify the risk factors for poor physical fitness (PPF) among 3- to 6-year-old children in the years 2005, 2010, and 2014 in the area of southwest Hubei of China.

Results

Of the 2128 children, 495 were classified as PPF (23.3%). In 2005, the percentage of PPF children was 21.7%, and the percentage of PPF children decreased from 29.1% in 2010 to 18.8% in 2014. Furthermore, Urban area children had a significant risk of PPF than rural area children (OR=1.299, P=0.031). Three-year-old children had 2.150-fold risk of PPF as compared to 6-year-old children. The children with less than 0.5 hours of activity time per day had 1.95-fold risk of PPF as compared to those with 1-2-hour activity time per day, respectively. Underweight and overweight/obese children had 2.74-fold and 1.67-fold risk of PPF as compared to normal weight children. Children had 1.97-fold risk of PPF when their father's schooling ceased after middle school and 1.51-fold risk of PPF when their father's schooling ceased after high school, respectively.

Conclusions

These results demonstrated that the incidence of PPF children went up from 2005 to 2010 and then down from 2010 to 2014 within the Tujia settlement. For the children in this area, the risk factors associated with PPF included urban location, younger age, less than 1-hour activity time per day in kindergarten, underweight/overweight, low father's education level, and mother's childbearing age being less than 20 years.

Association between maximal oxygen consumption and physical activity and sedentary lifestyle in metabolic syndrome. Usefulness of questionnaires

INTRODUCTION AND OBJECTIVES

To analyze whether variations in physical activity (PA) and sedentary behaviors are accompanied by differences in maximal oxygen consumption (VO_2max).

METHODS

We conducted a prospective cross-sectional study of 243 participants (82 women), aged 65.0±4.9 years old, with metabolic syndrome and overweight/obesity who performed a maximal exercise test with expired gas analysis. PA was evaluated using subjective methods, the REGICOR and RAPA 1 self-reported questionnaires, and objective methods, the chair test and accelerometry. Sedentariness was analyzed with the Nurses' Health Study questionnaire and accelerometry.

RESULTS

VO_2max was higher in participants who reported they adhered to the recommendations of the PA guidelines in the REGICOR questionnaire (21.3±4.6 vs 18.0±4.4 mL/kg/min; P <.001) and was 18% higher in those who reported more PA in the RAPA 1 questionnaire than the less active group (P <.001). The chair test (> 15 vs ≤ 15 repetitions) also showed significant differences in VO_2max (21.2±4.8 vs 18.7±4.5 ml/kg/min; P <.001). Correlations between PA variables and VO_2max were significant but low (r: 0.2 to 0.4). Sedentary activities showed less relationship with VO_2max.

CONCLUSIONS

Participants with metabolic syndrome and overweight/obesity who reported adhering to PA recommendations achieved higher VO_2max. The self-reported questionnaires and the chair test identified significant variations in VO_2max. Sedentary activities do not appear to modify VO_2max.

Associations between measures of health-related physical fitness and cardiometabolic risk factors in college students

OBJECTIVE

To determine the influence of health-related fitness on cardiometabolic risk factors in college students.

PARTICIPANTS

75 traditional students (33 men and 42 women, 21.8±1.8 years old) at a university in southeastern U.S.

METHODS

Height, weight, waist circumference, body composition, blood pressure, lipids, glucose, insulin, c-reactive protein, and glucose tolerance were measured. Indices of insulin sensitivity were calculated. Aerobic and muscular fitness were measured. Regression and correlation analyses, and comparisons of cardiometabolic markers in low- vs high-fit participants were performed.

RESULTS

Men and women with low muscular fitness exhibited higher fasting insulin, and poorer insulin sensitivity index scores than those with high muscular fitness. In addition, women with high body fat percentage exhibited higher fasting and 2-hour insulin levels and lower insulin sensitivity index scores than those with low body fat percentages.

CONCLUSIONS

College students possessing low levels of health-related physical fitness exhibited less favorable cardiometabolic risk profiles.

Association of domain-specific physical activity and cardiorespiratory fitness with all-cause and cause-specific mortality in two population-based cohort studies

Physical activity (PA) reduces the risk for mortality. Whether the beneficial effects of PA are domain specific is unclear. We associated leisure time (LTPA), sports (SPA) and work (WPA) related PA and cardiorespiratory fitness (CRF) with all-cause mortality in two German population-based cohorts. We used data of the Study of Health in Pomerania (SHIP, n = 2,935, median age 53; 48% male) and the Cardiovascular Disease, Living and Ageing in Halle study (CARLA, n = 1,776, median age 64 and 54% male). Mortality was determined after a median follow-up of 8.2 years in SHIP (n = 332) and 11.5 years in CARLA (n = 409). LTPA (SHIP: hazard ratio [HR] per standard deviation [SD] 0.82 95%-CI 0.73 to 0.91 and CARLA: HR per SD 0.70: 95%-CI 0.59 to 0.82) and SPA (SHIP: HR per SD 0.80 95%-CI 0.71 to 0.91 and CARLA: HR per SD 0.70 95%-CI 0.60 to 0.82) but not WPA were inversely associated with all-cause mortality. In a subsample CRF was inversely related to mortality and positively to LTPA and sports SPA. No association was found for WPA. Our results may suggest that the inverse association between PA and mortality are partly influenced by higher CRF.

Effect of high-intensity interval training on cardiovascular disease risk factors and body composition in psoriatic arthritis: a randomised controlled trial

Background

Psoriatic arthritis (PsA) is associated with an accumulation of cardiovascular disease (CVD) risk factors. The aim of this study was to evaluate the effect of high-intensity interval training (HIIT) on CVD risk factors in patients with PsA.

Methods

We randomly assigned 61 patients with PsA (41 women and 20 men) to an intervention group performing HIIT for 11 weeks or a control group who were instructed to not change their physical exercise habits. Outcomes were assessed at 3 and 9  months with measures on maximal oxygen uptake (VO_2max), fat percentage and Body Mass Index (BMI). We used linear mixed models to calculate mean difference with 95% CI between the groups according to the intention-to-treat principle.

Results

At 3  months, the HIIT group had a 3.72  mL/kg/min (95%  CI 2.38 to 5.06) higher VO_2max and a 1.28 (95% CI −2.51 to −0.05) lower truncal fat percentage than controls. There was also some evidence that the HIIT group had lower total fat percentage (−0.80; 95%  CI −1.71 to 0.10) and slightly lower BMI (−0.31; 95%  CI −0.78 to 0.17) than the control group. At 9  months, the HIIT group had still a higher VO_2max (3.08; 95%  CI 1.63 to 4.53) than the control group, whereas the difference in other factors were small.

Conclusion

In patients with PsA, 3  months with HIIT was associated with a substantial increase in VO_2max and a reduction in truncal fat percentage compared with controls. The beneficial effect on VO_2max was also sustained through 9  months.

Trial registration number

NCT02995460.

Precancer diagnosis cardiorespiratory fitness, physical activity and cancer mortality in men

BACKGROUND

The preventive role of precancer diagnosis cardiorespiratory fitness (CRF) and physical activity (PA) in cancer mortality is poorly characterized. The aim of this study was to assess the association between CRF, PA at precancer-diagnosis and cancer mortality in men who diagnosed with cancer later in life.

METHODS

A total of 699 men (63±10 years) who were diagnosed with cancer during 7.5±4.9 years from a baseline treadmill exercise test and reported PA were analyzed. Multivariate Cox models for CRF and univariate model for PA were conducted. Population Attributable Risks (PARs%) and exposure impact number (EIN) of low CRF (<5 METs) and inactivity were determined.

RESULTS

During 6.5±5.2 years from cancer diagnosis, 56% died from cancer. CRF was inversely, graded and independently associated with cancer death. A 1-MET increase and categories of moderate and high CRF were associated with 7%, 28% and 51% reductions in risk of cancer death, respectively. Active compared to inactive individuals had a 23% reduced risk of cancer mortality (HR=0.77, 95% CI [0.63-0.94], P=0.01). PARs% of low CRF and inactivity were 4.8% and 9.4%, respectively, while the respective EIN were 3 and 9.

CONCLUSIONS

Higher CRF and being active at precancer-diagnosis were associated with lower cancer mortality and longer survival time in men who developed cancer later in life. Screening and intervening for low CRF and inactivity as risk factors during middle-age and maintaining at least moderate CRF and activity levels may be effective strategies for prevention of cancer mortality.

Comparison of Serum Cytokine Levels in Men Who are Obese or Men Who are Lean: Effects of Nonlinear Periodized Resistance Training and Obesity

Nikseresht, M. Comparison of serum cytokine levels in men who are obese or men who are lean: effects of nonlinear periodized resistance training and obesity. J Strength Cond Res 32(6): 1787-1795, 2018-This study examined the capacity of nonlinear resistance training (NRT) to alter some cytokines and markers of insulin resistance in men who are obese. An additional aim was to compare these variables between men who are obese and men who are lean. Age- and fitness-matched men who are obese were randomly allocated to NRT (n = 12) and control (CON, n = 10) groups. An age- and fitness-matched control group of lean men (n = 11) were also recruited for baseline comparison. The NRT (12 weeks, 3 d·wk, 5-11 exercises) performed at different intensities (40-95% of 1 repetition maximum) with flexible periodization. Serum insulin, glucose, interleukin (IL)-6, IL-10, IL-17A, and IL-20 levels were measured at baseline and after training. Men who were obese had significantly lower IL-20 and higher glucose, insulin, insulin resistance (homeostasis model assessment, HOMA-IR), IL-10, and IL-6 than lean participants at baseline (all, p ≤ 0.05). There were significant negative correlations between IL-10 with anthropometric markers and HOMA-IR at baseline, whereas these variables were inversely correlated with IL-20. After training, V[Combining Dot Above]O2peak and 1 repetition maximum for bench press and knee extension of the NRT increased significantly compared with CON, which was accompanied by significant reductions in anthropometric markers, insulin and HOMA-IR. IL-6 and IL-17A did not change significantly in response to training, but IL-10 and IL-20 increased significantly compared with baseline. An inverse relationship between the percent IL-20 increase and the percent waist circumference decrease suggests that adipocytes, or other metabolic factors such as glucose, may exert a lowering-effect on IL-20.

The Associations between Dietary Patterns and Sedentary Behaviors in Polish Adults (LifeStyle Study)

Sedentary behavior, a low physical activity level, and unhealthy dietary patterns are risk factors for major chronic diseases, including obesity. The aim of this study was to assess the associations of dietary patterns (DPs) with sedentary behaviors (SB) and self-reported physical activity (PA). The data was collected in November 2016 through a cross-sectional quantitative survey amongst 1007 Polish adults. Principal components analysis (PCA) was conducted to derive DPs. Logistic regression analysis was used to verify associations between PA and SD (independent variables), and DPs (dependent variables). Five DPs ('Fast foods & sweets'-FF&S; 'Meat & meat products'-M&MP; 'Fruit & vegetable'-F&V; 'Wholemeal food'-WF; 'Fruit & vegetable juices'-F&VJ) were identified. Representing M&MP independently increased the chance of watching TV at least once a day (by 73%). There was no such relationship between the FF&S and sedentary behaviors. Being in the upper tertiles of pro-health DPs increased the chance of reading books (by 177%-F&V, 149%-WF, 54%-F&VJ) and watching TV (by 71%-F&V). On the other hand, belonging to the upper tertile of WF reduced the chance of using the computer for more than 4 h a day. Belonging to the upper tertile of healthy DPs (WF and F&VJ) increased the chances of moderate or high physical activity, both at work/school and during leisure time. Within F&V, there was a lower chance of moderate or high physical activity at work/school. Being in the upper tertile of unhealthy DPs (FF&S and M&MP) did not show any significant association with physical activity. The study indicated the associations between both healthy and unhealthy DPs and some sedentary behaviors. Association between F&V and watching TV and reading books/newspapers should be recognized as potentially efficient in education. Association between M&MP and watching television can be indicative of the mutual overlap of a negative lifestyle resulting in the development of overweight and obesity, especially since the extent of occurrence of sedentary behaviors is high.

Exercise as an intervention for first-episode psychosis: a feasibility study

AIM

Exercise can improve psychiatric symptoms, neurocognitive functioning and physical health in schizophrenia. However, the effects in early psychosis have not been explored. This study aimed to assess the feasibility of an exercise intervention for early psychosis and to determine if it was associated with changes in physical and mental health.

METHODS

Thirty-one patients with first-episode psychosis (FEP) were recruited from early intervention services to a 10-week exercise intervention. The intervention group received individualized training programmes, aiming to achieve ≥90 min of moderate-to-vigorous activity each week, using exercise programmes tailored to individual preferences and needs. A comparison FEP sample from the same services (n = 7) received treatment as usual.

RESULTS

Rates of consent and retention in the exercise group were 94% and 81%, respectively. Participants achieved an average of 107 min of moderate-to-vigorous exercise per week. Positive and Negative Syndrome Scale total scores reduced by 13.3 points after 10 weeks of exercise, which was significantly greater than the treatment as usual comparison group (P = 0.010). The greatest differences were observed in negative symptoms, which reduced by 33% in the intervention group (P = 0.013). Significant improvements were also observed in psychosocial functioning and verbal short-term memory. Increases in cardiovascular fitness and processing speed were positively associated with the amounts of exercise achieved by participants.

CONCLUSION

Individualized exercise training could provide a feasible treatment option for improving symptomatic, neurocognitive and metabolic outcomes in FEP.

The Relationship between Cardiorespiratory Fitness and Montreal Cognitive Assessment Scores in Older Adults

BACKGROUND

Relatively little is known regarding the association between objective measures of physical function such as cardiorespiratory fitness (CRF) and cognitive function tests in healthy older adults.

OBJECTIVE

To evaluate the relationship between CRF and cognitive function in adults aged 55 and older.

METHODS

Between 2008 and 2017, 4,931 men and women underwent a comprehensive preventive physical exam at the Cooper Clinic in Dallas, Texas. CRF was determined by duration of a maximal treadmill exercise test. Cognitive function was evaluated with the Montreal Cognitive Assessment (MoCA). In a multivariate model, adjusted odds ratios with 95% confidence intervals for MoCA scores < 26 (i.e., cognitive impairment) were determined by using CRF as both a continuous and a categorical variable.

RESULTS

The mean age of the sample was 61.0 ± 6.0 years; mean maximal MET values were 10.0 ± 2.2. Mean MoCA scores were 26.9 ± 2.2; 23.4% of the sample had MoCA scores indicative of cognitive impairment. The odds ratio for cognitive impairment was 0.93 (0.88-0.97) per 1-MET increment in CRF. When examined as a categorical variable, and using the lowest CRF quintile as the referent, there was a significantly reduced likelihood for cognitive impairment across the remaining ordered CRF categories (p trend = 0.004).

CONCLUSION

The association between CRF and MoCA score in older adults suggests that meeting or exceeding public health guidelines for physical activity is likely to increase CRF in low fit individuals, maintain CRF in those with a moderate to high level of CRF, and thereby help to maintain cognitive function in healthy older adults.

Cardiorespiratory Fitness and Health Outcomes: A Call to Standardize Fitness Categories

An inverse association between physical activity or fitness status and health outcomes has been reported by several cohort studies. When fitness categories are established in quartiles or quintiles based on the peak exercise capacity achieved, the association is graded. Although significant health benefits of increased cardiorespiratory fitness (CRF) have been uniformly reported, the degree of protection has varied substantially between studies. This variability is likely due to varying methods used to define CRF categories, and not considering age, despite its strong effect on CRF. To ameliorate these methodological discrepancies, we propose standardized guidelines by which age-specific CRF categories should be defined.

Cardiorespiratory fitness versus physical activity as predictors of all-cause mortality in men

BACKGROUND

Although both cardiorespiratory fitness (CRF) and physical activity (PA) are associated with mortality, whether they are associated with all-cause mortality independent of each other is unclear.

METHODS

CRF was assessed by a maximal exercise test and PA was measured by self-report in 8,171 male veterans. The predictive power of CRF and PA, along with clinical variables, was assessed for all-cause mortality during a mean (±SD) follow-up 8.7 (4.4) years during which there were 1,349 deaths.

RESULTS

CRF was associated with mortality after adjusting for clinical variables and remained a strong predictor of mortality after further adjusting for PA (hazard ratio 0.85, 95% CI 0.83-0.87). PA was a significant predictor of mortality after controlling for clinical variables; however, the association was eliminated after further adjusting for CRF (hazard ratio 0.98, 95% CI 0.88-1.10). In CRF-stratified analysis, being active (≥150 min/wk) was not associated with mortality within the unfit or fit categories (P>.4). However, in PA-stratified analysis, subjects categorized as fit (≥7 metabolic equivalents [METS]) had a lower risk of mortality regardless of PA status (P<.001).

CONCLUSIONS

In adult men, PA was associated with mortality independent of established risk factors, but not CRF. Conversely, CRF remained a strong predictor of mortality independent of PA status and established risk factors.

Using Metabolic Equivalents in Clinical Practice

Metabolic equivalents, or METs, are routinely employed as a guide to exercise training and activity prescription and to categorize cardiorespiratory fitness (CRF). There are, however, inherent limitations to the concept, as well as common misapplications. CRF and the patient's capacity for physical activity are often overestimated and underestimated, respectively. Moreover, frequently cited fitness thresholds associated with the highest and lowest mortality rates may be misleading, as these are influenced by several factors, including age and gender. The conventional assumption that 1 MET = 3.5 mL O₂/kg/min has been challenged in numerous studies that indicate a significant overestimation of actual resting energy expenditure in some populations, including coronary patients, the morbidly obese, and individuals taking β-blockers. These data have implications for classifying relative energy expenditure at submaximal and peak exercise. Heart rate may be used to approximate activity METs, resulting in a promising new fitness metric termed the "personal activity intelligence" or PAI score. Despite some limitations, the MET concept provides a useful method to quantitate CRF and define a repertoire of physical activities that are likely to be safe and therapeutic. In conclusion, for previously inactive adults, moderate-to-vigorous physical activity, which corresponds to ≥3 METs, may increase MET capacity and decrease the risk of future cardiac events.