Exercise, body mass index, caloric intake, and cardiovascular mortality

Health Orientation as a Psychographic Framework for Understanding Physical Exercise Behavior

The consistent association between regular physical exercise and positive health outcomes presents a compelling case for investigating the differences between individuals who exercise regularly and those who do not. Based on a randomized cross-sectional survey of 1,201 households, this study adopts a psychographic framework to investigate the role of health orientation in physical exercise behavior. This study extends the concept of health orientation, operationalized as five psychographic subscales (health information orientation, preventative orientation, exercise orientation, healthy eating orientation, and health information efficacy) as well as three behavioral constructs (sedentary behavior, BMI and cigarette smoking) to understand physical exercise behavior. The results show significant differences between regular exercisers and non-exercisers, and suggest that a psychographic framework based on health orientation could offer a more holistic approach for understanding physical exercise behavior by highlighting the treatment of the whole individual. Physical exercise, as a specific health behavior, is in fact interlinked with other health behaviors through an underlying health orientation toward health issues in general.

Factors Associated with Body Weight Gain among Korean Adults during the COVID-19 Pandemic

Background

Obesity is of grave concern as a comorbidity of coronavirus disease 2019 (COVID-19). We examined the factors associated with weight gain among Korean adults during the COVID-19 pandemic.

Methods

We conducted an online survey of 1,000 adults (515 men and 485 women aged 20-59 years) in March 2021. Multivariable logistic regression analysis was performed to evaluate the factors associated with weight gain. The analysis was adjusted for sex, age, region, depressive mood, anxiety, eating out, late-night meals, alcohol consumption, exercise, sleep disturbance, meal pattern, subjective body image, comorbidities, marital status, living alone, and income.

Results

After adjusting for confounding variables, the odds for weight gain increased in the group aged 20-34 years compared with the group aged 50-59 years (1.82; 95% confidence interval [CI], 1.01-3.32). Women were more associated with the risk of weight gain compared with men. The odds for weight gain increased in the lack of exercise group compared with the exercise group (4.89; 95% CI, 3.09-7.88). The odds for weight gain increased in the eating-out and late-night meal groups compared with that in the groups not eating out and not having late-night meals. Individuals watching a screen for 3-6 hr/day were more associated with the risk of weight gain compared with those who rarely watched a screen. The odds for weight gain increased in participants who considered themselves obese compared with those who did not consider themselves obese.

Conclusion

A healthy diet and regular physical activity tend to be the best approach to reduce obesity, a risk factor for COVID-19.

Synergistic Assessment of Mortality Risk According to Body Mass Index and Exercise Ability and Capacity in Patients Referred for Radionuclide Stress Testing

OBJECTIVE

To determine the interrelationship between body mass index (BMI), mode of stress testing (exercise or pharmacological), exercise capacity, and all-cause mortality in patients referred for stress-rest single photon emission computed tomography myocardial perfusion imaging.

PATIENTS AND METHODS

We evaluated all-cause mortality in 21,638 patients undergoing stress-rest single photon emission computed tomography myocardial perfusion imaging between January 2, 1991, and December 31, 2012. Patients were divided into exercise and pharmacologically tested groups and 9 BMI categories. The median follow-up was 12.8 years (range, 5.0-26.8 years).

RESULTS

In exercise patients, mortality was increased with both low and high BMI vs patients with a normal referent BMI of 22.5 to 24.9 kg/m². In pharmacologically tested patients, only low BMI, but not high BMI, was associated with increased mortality vs normal BMI. When exercise and pharmacologically tested groups were compared directly, pharmacologically tested patients manifested a marked increase in mortality risk vs exercise patients within each BMI category, ranging from an approximately 4-fold increase in mortality in those with normal or high BMI to a 12.3-fold increase in those with low BMI values. Similar findings were observed in a cohort of 4804 exercise and 4804 pharmacologically tested patients matched to have similar age and coronary artery disease risk factor profiles. In exercise patients, further risk stratification was achieved when considering both BMI and metabolic equivalent tasks of achieved exercise.

CONCLUSION

The combined assessment of BMI and exercise ability and capacity provides synergistic and marked risk stratification of future mortality risk in patients referred for radionuclide stress testing, providing considerable insights into the "obesity paradox" that is observed in populations referred for stress testing.

Association between physical activity level and blood pressure: varied and graded mediating effects of obesity indices in schoolchildren

OBJECTIVE

To explore the mediating effects of adiposity indices in the association between physical activity level and blood pressure in a Nigerian schoolchildren population.

MATERIALS AND METHODS

One thousand five hundred and seventeen schoolchildren (714 males and 803 females) from randomly selected primary schools participated. Physical activity level, sum of skinfold thickness at three sites, waist circumference, body mass index, and blood pressure were measured using standardised procedures. The statistical significance of the mediating effects of adiposity indices was determined using Sobel Test.

RESULTS

Some obesity indices mediated the association between physical activity level and systolic blood pressure in males [waist circumference (t = 5.31; p < 0.001), skin-fold thickness (t = 3.80; p < 0.001) and waist-circumference/height (t = 2.21; p < 0.001)] and in females [body mass index (t = 8.03; p < 0.001), waist circumference (t = 7.80; p < 0.001), and skin-fold thickness (t = 5.94; p < 0.001)]. Similarly, some obesity indices mediated the association of physical activity and diastolic blood pressure in males [body mass index (t = 1.95; p = 0.05), waist circumference (t = 2.65; p = 0.01), and skin-fold thickness (t = 1.97; p = 0.05)], and in females [body mass index (t = 6.49; p < 0.001), waist circumference (t = 6.29; p < 0.001), skin-fold thickness (t = 2.31; p = 0.02) and waist-circumference/Height (t = 2.59; p = 0.01)].

CONCLUSION

The obesity indices that mediate the association between physical activity level and blood pressure vary, and their mediating effects are graded. While waist circumference and skinfold thickness exert the greatest mediating effects on the association in males, body mass index and waist circumference do in females.

Dietary Determinants of Metabolic Syndrome Parameters Differ by Gender in College Students

MyPlate is a guidance system for healthier eating choices. In this cross-sectional study, we investigated the influence of MyPlate food group consumption and exercise on metabolic syndrome (MetS) parameters in college students. Participant (n = 462) blood was analyzed using Cholestech for triglycerides (TG), glucose, low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C). In addition, weight, waist circumference (WC), and blood pressure (BP) were measured. Diet and Wellness Plus was used to compute participant diet records. Regression analysis and a recursive decision tree were made to predict MetS using RStudio (V.1.1.463). BP decision tree predicted high risk of elevated blood pressure with a recall rate of 93.7%. For males; exercise, empty calories, dairy, and protein were main predictors. For females, vegetable and empty calorie consumption were primary determinants. HDL-C decision tree had a recall rate of 91.8% and showed that the main low HDL-C risk determinants for males were; exercise and grain consumption. Conversely, for females; empty calories, grain, and vegetable consumption were the key factors determining low HDL-C risk. This study shows that MyPlate recommendations are valuable to achieve adequate HDL-C and blood pressure and provides insight into the importance of tailoring food intake guidance based on gender.

BDNF contributes to the skeletal muscle anti-atrophic effect of exercise training through AMPK-PGC1α signaling in heart failure mice

INTRODUCTION

Exercise training is a coadjuvant therapy in preventive cardiology, and it delays cardiac dysfunction and exercise intolerance in heart failure (HF). However, the mechanisms underlying muscle function improvement and cardioprotection are poorly understood. In this study, we tested whether exercise training would counteract skeletal muscle atrophy via activation of the BDNF pathway in myocardial infarction (MI)-induced HF mice.

MATERIAL AND METHODS

A cohort of male Sham-operated and MI mice were assigned into 8-week moderate exercise training, and untrained counterparters were used as control. Exercise capacity, plasma norepinephrine (NE) level, heart rate (HR), fractional shortening (FS) and ejection fraction (EF) were measured. The protein expression of BDNF, p-TrkB, p-AMPK and PGC1α were analyzed by Western blot.

RESULTS

Compared with the Sham-operated mice, MI mice displayed reduced total distance run and elevated plasma NE level (both p < 0.05). Exercise training significantly improved distance run and plasma NE levels in HF mice (both p < 0.05). Significantly increased HR, decreased FS and EF were observed in the MI group as compared to the Sham-operated group, and exercise training prevent the hemodynamic status and systolic dysfunction in MI mice (all p < 0.05). The expression of BDNF, p-TrkB, p-AMPK and PGC1α were significantly decreased in the skeletal muscle from MI compared to Sham-operated mice, which were significantly increased by exercise training (all p < 0.05). In addition, BDNF siRNA markedly decreased the protein level of p-AMPK and PGC1α in C2C12 myoblasts.

CONCLUSIONS

Taken together, our data provide evidence for exercise training may counteract HF-induced muscle atrophy through induced activation of BDNF pathway.

Nutritional risk index as a predictor of mortality in acutely decompensated heart failure

BACKGROUND

We investigated the role of nutritional risk index (NRI) in predicting 1-year mortality in patients with acute decompensated heart failure (ADHF).

METHODS

Among 5,625 cohort patients enrolled in Korean Acute Heart Failure (KorAHF) Registry, a total of 5,265 patients who were possible to calculate NRI [NRI = (1.519 x serum albumin [g/dl]) + (41.7 x weight [kg]/ideal body weight [kg])] were enrolled. The patients were divided into 4 groups according to the NRI quartile; Q1 <89 (n = 1121, 69.9 ± 14.5 years, 632 males), Q2 89-95 (n = 1234, 69.7 ± 14.4 years, 677 males), Q3 95-100 (n = 1199, 68.8 ± 14.0 years, 849 males), Q4 >100 (n = 1711, 65.6 ± 14.5 years, 779 males). Primary end-point was all-cause mortality at 1-year clinical follow-up.

RESULTS

The 1-year mortality was significantly increased as the NRI quartile decreased, and the lowest NRI quartile was associated with the highest 1-year mortality (Q1: 27.5% vs. Q2: 20.9% vs. Q3: 12.9% vs. Q4: 8.7%, linear p <0.001). On Kaplan-Meier survival analysis, the significant inter-quartile difference was observed (p <0.001 for all). In multivariate analysis using Cox proportional hazard regression, the lowest NRI quartile was an independent predictor of 1-year mortality in patients with ADHF.

CONCLUSIONS

Poor nutritional status as assessed by NRI and quartile grading of NRI was associated with 1-year mortality in Korean patients with ADHF. The assessment of nutritional status by NRI may provide additional prognostic information and thus would be useful in the risk stratification of the patients with ADHF.

Associations of leisure-time physical activity with cardiovascular mortality: A systematic review and meta-analysis of 44 prospective cohort studies

Background

Many cohort studies within the past few decades have shown the protective effect of leisure-time physical activity on cardiovascular mortality. To summarise the evidence from prospective cohort studies on the relationship between the amount of leisure-time physical activity and the risk of cardiovascular mortality, a dose–response meta-analysis was conducted in this study.

Methods and results

Electronic databases, including PubMed and Embase databases, Scopus and Cochrane Library, were systemically retrieved by two investigators from inception to 14 June 2018 for related studies. The maximum adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) were extracted, and a dose–response analysis was conducted using the restricted cubic splines. Finally, a total of 44 studies comprising 1,584,181 participants was enrolled into this meta-analysis. The HRs of cardiovascular mortality for moderate and high leisure-time physical activity were 0.77 (95% CI 0.74–0.81) and 0.73 (95% CI 0.69–0.77), respectively. Among these 44 studies, 19 were eligible for the dose–response meta-analysis, which suggested a linear negative correlation of leisure-time physical activity with cardiovascular mortality, regardless of age, gender and the presence of underlying cardiovascular disease or not.

Conclusions

Leisure-time physical activity shows a linear negative correlation with the risk of cardiovascular mortality regardless of age, gender and the presence of cardiovascular disease or not. However, the cardiovascular benefits of leisure-time physical activity is decreased for those aged over 65 years or those with a history of cardiovascular disease. Moreover, leisure-time physical activity displays more cardiovascular benefits to people followed up for over 10 years than to those followed up for less than 10 years. Besides, high-intensity leisure-time physical activity has more obvious cardiovascular benefits than those of moderate-intensity leisure-time physical activity.

Using Machine Learning to Define the Association between Cardiorespiratory Fitness and All-Cause Mortality (from the Henry Ford Exercise Testing Project)

Previous studies have demonstrated that cardiorespiratory fitness is a strong marker of cardiovascular health. Machine learning (ML) can enhance the prediction of outcomes through classification techniques that classify the data into predetermined categories. The aim of the analysis is to compare the prediction of 10 years of all-cause mortality (ACM) using statistical logistic regression (LR) and ML approaches in a cohort of patients who underwent exercise stress testing. We included 34,212 patients (55% males, mean age 54 ± 13 years) free of coronary artery disease or heart failure who underwent exercise treadmill stress testing between 1991 and 2009 and had complete 10-year follow-up. The primary outcome of this analysis was ACM at 10 years. The probability of 10-years ACM was calculated using statistical LR and ML, and the accuracy of these methods was calculated and compared. A total of 3,921 patients died at 10 years. Using statistical LR, the sensitivity to predict ACM was 44.9% (95% confidence interval [CI] 43.3% to 46.5%), whereas the specificity was 93.4% (95% CI 93.1% to 93.7%). The sensitivity of ML to predict ACM was 87.4% (95% CI 86.3% to 88.4%), whereas the specificity was 97.2% (95% CI 97.0% to 97.4%). The ML approach was associated with improved model discrimination (area under the curve for ML [0.923 (95% CI 0.917 to 0.928)]) compared with statistical LR (0.836 [95% CI 0.829 to 0.846], p<0.0001). In conclusion, our analysis demonstrates that ML provides better accuracy and discrimination of the prediction of ACM among patients undergoing stress testing.

Longitudinal changes in physical activity, sedentary behavior and body mass index in adolescence: Migrations towards different weight cluster

This study examined longitudinal changes in physical activity, sedentary behavior and body mass index in adolescents, specifically their migrations towards a different weight cluster. A cohort of 755 adolescents participated in a three-year study. A clustering Self-Organized Maps Analysis was performed to visualize changes in subjects' characteristics between the first and second assessment, and how adolescents were grouped. Also a classification tree was used to identify the behavioral characteristics of the groups that changed their weight cluster. Results indicated that boys were more active and less sedentary than girls. Boys were especially keen to technological-based activities while girls preferred social-based activities. A moderate competing effect between sedentary behaviors and physical activities was observed, especially in girls. Overweight and obesity were negatively associated with physical activity, although a small group of overweight/obese adolescents showed a positive relationship with vigorous physical activity. Cluster migrations indicated that 22.66% of adolescents changed their weight cluster to a lower category and none of them moved in the opposite direction. The behavioral characteristics of these adolescents did not support the hypothesis that the change to a lower weight cluster was a consequence of an increase in time devoted to physical activity or a decrease in time spent on sedentary behavior. Physical activity and sedentary behavior does not exert a substantial effect on overweight and obesity. Therefore, there are other ways of changing to a lower-weight status in adolescents apart from those in which physical activity and sedentary behavior are involved.

Physical activity levels and pattern of use for youth participants at a traditional aquatic venue

In an effort to encourage youth to acquire recommended levels of moderate to vigorous physical activity (MVPA), we need to examine affordances available to enhance opportunities. Included for consideration should be built environments such as swimming pools which can have significant impacts through leisure service delivery to promote active lifestyles. For this study, The System for Observing Play and Recreation in Communities (SOPARC), was employed at a traditional aquatic venue during July and August in the Midwestern region of the U.S. Data was collected on three physical activity postures for youths age 4 to 18 along with variables including: (a) age, (b) gender, (c) physical activity posture, and (d) areas of participation termed target areas. A total of 3780 observations were taken into account during analysis. To detect differences among key variables, One-Way ANOVA and t-tests were performed. Descriptive results indicated that MVPA accounted for 70% of activity in the aquatic venue. Overall, female youths generated more MVPA within target areas compared to males, and youth as a single group consistently scored higher in all target areas as well as overall in MVPA. Significant differences were discovered in relation to several target areas. Findings from the study indicate that the use of a traditional aquatic venue can have positive impacts on youth physical activity and assist in meeting national standards for daily requirements of MVPA. It is also indicated that design features of an aquatic venue can play a role in determining levels of engagement and physical activity.

Experimental Evidences Supporting the Benefits of Exercise Training in Heart Failure

Heart Failure (HF), a common end point for many cardiovascular diseases, is a syndrome with a very poor prognosis. Although clinical trials in HF have achieved important outcomes in reducing mortality, little is known about functional mechanisms conditioning health improvement in HF patients. In parallel with clinical studies, basic science has been providing important discoveries to understand the mechanisms underlying the pathophysiology of HF, as well as to identify potential targets for the treatment of this syndrome. In spite of being the end-point of cardiovascular derangements caused by different etiologies, autonomic dysfunction, sympathetic hyperactivity, oxidative stress, inflammation and hormonal activation are common factors involved in the progression of this syndrome. Together these causal factors create a closed link between three important organs: brain, heart and the skeletal muscle. In the past few years, we and other groups have studied the beneficial effects of aerobic exercise training as a safe therapy to avoid the progression of HF. As summarized in this chapter, exercise training, a non-pharmacological tool without side effects, corrects most of the HF-induced neurohormonal and local dysfunctions within the brain, heart and skeletal muscles. These adaptive responses reverse oxidative stress, reduce inflammation, ameliorate neurohormonal control and improve both cardiovascular and skeletal muscle function, thus increasing the quality of life and reducing patients' morbimortality.

Association between Adiposity and disability in the Lc65+ Cohort

OBJECTIVES

To examine the longitudinal association between body mass index (BMI) and waist circumference (WC) with mortality and incident disability in Lc65+ cohort.

DESIGN

Population-based cohort of non-institutionalized adults with up to 8.9 years of follow-up.

SETTING

City of Lausanne, Switzerland.

PARTICIPANTS

1,293 individuals aged 65 to 70 at baseline (58% women).

MEASUREMENTS

BMI, WC and covariates were measured at baseline in 2004-2005. Vital status was obtained up to the 31st December 2013 and difficulty with basic activities of daily living (BADL) was reported in a self-administered questionnaire sent to participants every year. Main outcomes were total mortality and disability, defined as difficulty with BADL for ≥2 years or institutionalization. Cox regression was used with BMI/WC quintiles 2 as the reference.

RESULTS

130 persons died over a median follow-up of 8.47 years (crude mortality rate, men: 16.5/1,000 person-years, women: 9.7/1,000 person-years). In Cox regression adjusted for age, sex, education, financial situation, smoking and involuntary weight loss (IWL) at baseline, mortality was significantly associated with neither BMI nor WC, but there were trends towards non-significant J-curves across both BMI and WC quintiles. Disability (231 cases) tended to increase monotonically across both BMI and WC quintiles and was significantly associated with BMI quintile 5 (HR=2.44, 95% CI [1.65-3.63]), and WC quintiles 4 (HR=1.81 [1.15-2.85]) and 5 (HR=2.58, [1.67-4.00]).

CONCLUSION

Almost half of the study population had a substantially increased HR of disability, as compared to the reference BMI/WC categories. This observation emphasizes the need for life-long strategies aimed at preventing excess weight, muscle loss and functional decline through adequate nutrition and regular physical activity, starting at early age and extending throughout life.

Racial Differences in the Prognostic Value of Cardiorespiratory Fitness (Results from the Henry Ford Exercise Testing Project)

The aim of this analysis was to determine whether racial differences exist in the prognostic value of cardiorespiratory fitness (CRF) in black and white patients undergoing stress testing. We included 53,876 patients (mean age 53 ± 13, 49% women) from the Henry Ford Exercise Testing project free of established coronary disease or heart failure who completed a maximal exercise test from 1991 to 2009. Patients were followed for a mean duration of 11.5 years for all-cause mortality, ascertained by linkage with the Death Master File. Follow-up over mean 6.2 years was also available for incident myocardial infarction. Multivariate Cox proportional hazards regression models were used adjusting for demographic variables, risk factors, medications, and reason for stress test referral, including formal interaction testing by race (black vs white). Black patients (n = 16,725) were younger (54 ± 13 vs 52 ± 13, p <0.001) but had higher prevalence of hypertension (73% vs 57%, p <0.001) and obesity (28% vs 21%, p <0.001). On average, black patients achieved a lower CRF compared with whites (8.4 vs 9.5 metabolic equivalents, p <0.0001). A graded increase in mortality risk was noted with decreasing CRF for both black and white patients. In multivariate Cox regression, CRF was a predictor of both myocardial infarction and mortality, with no significant interaction between race, fitness, and outcomes (all interaction terms p >0.10). CRF is a strong predictor of all-cause mortality in both white and black patients, with no significant interaction observed between race, fitness, and outcomes.

Aerobic Exercise and Pharmacological Therapies for Skeletal Myopathy in Heart Failure: Similarities and Differences

Skeletal myopathy has been identified as a major comorbidity of heart failure (HF) affecting up to 20% of ambulatory patients leading to shortness of breath, early fatigue, and exercise intolerance. Neurohumoral blockade, through the inhibition of renin angiotensin aldosterone system (RAS) and β-adrenergic receptor blockade (β-blockers), is a mandatory pharmacological therapy of HF since it reduces symptoms, mortality, and sudden death. However, the effect of these drugs on skeletal myopathy needs to be clarified, since exercise intolerance remains in HF patients optimized with β-blockers and inhibitors of RAS. Aerobic exercise training (AET) is efficient in counteracting skeletal myopathy and in improving functional capacity and quality of life. Indeed, AET has beneficial effects on failing heart itself despite being of less magnitude compared with neurohumoral blockade. In this way, AET should be implemented in the care standards, together with pharmacological therapies. Since both neurohumoral inhibition and AET have a direct and/or indirect impact on skeletal muscle, this review aims to provide an overview of the isolated effects of these therapeutic approaches in counteracting skeletal myopathy in HF. The similarities and dissimilarities of neurohumoral inhibition and AET therapies are also discussed to identify potential advantageous effects of these combined therapies for treating HF.

Exercise and the cardiovascular system: clinical science and cardiovascular outcomes

Substantial evidence has established the value of high levels of physical activity, exercise training (ET), and overall cardiorespiratory fitness in the prevention and treatment of cardiovascular diseases. This article reviews some basics of exercise physiology and the acute and chronic responses of ET, as well as the effect of physical activity and cardiorespiratory fitness on cardiovascular diseases. This review also surveys data from epidemiological and ET studies in the primary and secondary prevention of cardiovascular diseases, particularly coronary heart disease and heart failure. These data strongly support the routine prescription of ET to all patients and referrals for patients with cardiovascular diseases, especially coronary heart disease and heart failure, to specific cardiac rehabilitation and ET programs.

Classification of accelerometer wear and non-wear events in seconds for monitoring free-living physical activity

OBJECTIVE

To classify wear and non-wear time of accelerometer data for accurately quantifying physical activity in public health or population level research.

DESIGN

A bi-moving-window-based approach was used to combine acceleration and skin temperature data to identify wear and non-wear time events in triaxial accelerometer data that monitor physical activity.

SETTING

Local residents in Swansea, Wales, UK.

PARTICIPANTS

50 participants aged under 16 years (n=23) and over 17 years (n=27) were recruited in two phases: phase 1: design of the wear/non-wear algorithm (n=20) and phase 2: validation of the algorithm (n=30).

METHODS

Participants wore a triaxial accelerometer (GeneActiv) against the skin surface on the wrist (adults) or ankle (children). Participants kept a diary to record the timings of wear and non-wear and were asked to ensure that events of wear/non-wear last for a minimum of 15 min.

RESULTS

The overall sensitivity of the proposed method was 0.94 (95% CI 0.90 to 0.98) and specificity 0.91 (95% CI 0.88 to 0.94). It performed equally well for children compared with adults, and females compared with males. Using surface skin temperature data in combination with acceleration data significantly improved the classification of wear/non-wear time when compared with methods that used acceleration data only (p<0.01).

CONCLUSIONS

Using either accelerometer seismic information or temperature information alone is prone to considerable error. Combining both sources of data can give accurate estimates of non-wear periods thus giving better classification of sedentary behaviour. This method can be used in population studies of physical activity in free-living environments.

Associations Between Physical Activity and Metabolic Syndrome: Comparison Between Self-Report and Accelerometry

PURPOSE

To assess the relationship between self-reported and objectively measured physical activity (PA) and metabolic syndrome and its risk factors in U.S. adults.

DESIGN

A cross-sectional design was used for this study.

SETTING

The study was set among a nationally representative sample of U.S. adults.

SUBJECTS

Adults, ages 20 years and older, from the National Health and Nutrition Examination Survey (NHANES) 2003-2006 (n = 5580) participated in the study.

MEASURES

PA measures included minutes per week of moderate plus vigorous PA estimated by self-report (MVPAsr), total 7-day accelerometry (MVPAa), and accelerometer-based MVPA performed in 10-minute bouts (MVPAb). Risk factors for metabolic syndrome included blood pressure, high-density lipoprotein cholesterol, triglycerides, glucose, and waist circumference.

ANALYSIS

Odds ratios (ORs) for having metabolic syndrome were calculated for men and women who met the Physical Activity Guidelines for Americans compared to those who did not.

RESULTS

Women who did not meet the PA guidelines had significantly greater odds of having metabolic syndrome according to MVPAsr (OR = 2.20; 95% confidence interval [CI] = 1.65-2.94), MVPAa (OR = 4.40; 95% CI = 2.65-7.31), and MVPAb (OR = 2.91; 95% CI = 1.42-5.96). Men had significantly higher odds of having metabolic syndrome according to MVPAa (OR = 2.57; 95% CI = 1.91-3.45) and MVPAb (OR = 2.83; 95% CI = 1.55-5.17), but not MVPAsr. These ORs remained significant after adjusting for all potential confounders except body mass index, after which only MVPAsr in women and MVPAb in men remained significant.

CONCLUSION

Individuals who do not meet the PA guidelines exhibited greater odds of having metabolic syndrome. This relationship tended to be stronger for objective PA measures than for self-report.

Heritability and genetic etiology of habitual physical activity: a twin study with objective measures

Twin studies with objective measurements suggest habitual physical activity (HPA) are modestly to highly heritable, depending on age. We aimed to confirm or refute this finding and identify relevant genetic variants using a candidate gene approach. HPA was measured for 14 days with a validated triaxial accelerometer (Tracmor) in two populations: (1) 28 monozygotic and 24 dizygotic same-sex twin pairs (aged 22 ± 5 years, BMI 21.8 ± 3.4 kg/m(2), 21 male, 31 female pairs); (2) 52 and 65 unrelated men and women (aged 21 ± 2 years, BMI 22.0 ± 2.5 kg/m(2)). Single nucleotide polymorphisms (SNPs) in PPARD, PPARGC1A, NRF1 and MTOR were considered candidates. Association analyses were performed for both groups separately followed by meta-analysis. Structural equation modeling shows significant familiality for HPA, consistent with a role for additive genetic factors (heritability 57 %, 95 % CI 32-74 %, AE model) or common environmental factors (47 %, 95 % CI 23-65 %, CE model). A moderate heritability was observed for the time spent on low- and high-intensity physical activity (P ≤ 0.05), but could not be confirmed for the time spent on moderate-intensity physical activity. For PPARD, each additional effect allele was inversely associated with HPA (P ≤ 0.01; rs2076168 allele C) or tended to be associated with HPA (P ≤ 0.05; rs2267668 allele G). Linkage disequilibrium existed between those two SNPs (alleles A/G and A/C, respectively) and meta-analysis showed that carriers of the AA GC haplotype were less physically active than carriers of the AA AA and AA AC haplotypes combined (P = 0.017). For PPARGC1A, carriers of AA in rs8192678 spent more time on high-intensity physical activity than GG carriers (P = 0.001). No associations were observed with SNPs in NRF1 and MTOR. In conclusion, HPA may be modestly heritable, which is confirmed by an association with variants in PPARD.

Physical activity and cardiovascular disease in African Americans in Atherosclerosis Risk in Communities

PURPOSE

Although there is substantial evidence that physical activity reduces a person's risk of cardiovascular disease (CVD), few of these studies have included African Americans. The studies that have included African Americans offer inconclusive evidence on the association, and none studied heart failure separately. We used data from the Atherosclerosis Risk in Communities study cohort to examine, in African Americans, the association of physical activity with the incidence of CVD and its major components-stroke, heart failure, and CHD.

METHODS

Participants age 45-64 yr (3707 African Americans and, for comparison, 10,018 Caucasians) had physical activity assessed via questionnaire in 1987 and were followed for incident CVD (n = 1039) through 2008.

RESULTS

After adjustment for potential confounders, physical activity was inversely related to CVD, heart failure, and CHD incidence in both races (P values for trend <0.0001), and with stroke in African Americans. Hazard ratios (95% confidence intervals) for CVD for each higher physical activity category were similar by race: 1.0, 0.65 (0.56-0.75), and 0.59 (0.49-0.71) for African Americans and 1.0, 0.74 (0.66-0.83), and 0.67 (0.59-0.75) for Caucasians (P value for interaction = 0.38).

CONCLUSIONS

Our findings reinforce recommendations that regular physical activity is important for CVD risk reduction in African Americans as well as Caucasians and support the idea that some physical activity is better than none.

Physical activity and other health behaviors in adults with hypertrophic cardiomyopathy

The clinical expression of hypertrophic cardiomyopathy (HC) is undoubtedly influenced by modifying genetic and environmental factors. Lifestyle practices such as tobacco and alcohol use, poor nutritional intake, and physical inactivity are strongly associated with adverse cardiovascular outcomes and increased mortality in the general population. Before addressing the direct effect of such modifiable factors on the natural history of HC, it is critical to define their prevalence in this population. A voluntary survey, drawing questions in part from the 2007 to 2008 National Health and Nutrition Examination Survey (NHANES), was posted on the HC Association website and administered to patients with HC at the University of Michigan. Propensity score matching to NHANES participants was used. Dichotomous and continuous health behaviors were analyzed using logistic and linear regression, respectively, and adjusted for body mass index and propensity score quintile. Compared to the matched NHANES participants, the patients with HC reported significantly less alcohol and tobacco use but also less time engaged in physical activity at work and for leisure. Time spent participating in vigorous or moderate activity was a strong predictor of self-reported exercise capacity. The body mass index was greater in the HC cohort than in the NHANES cohort. Exercise restrictions negatively affected emotional well-being in most surveyed subjects. In conclusion, patients with HC are less active than the general United States population. The well-established relation of inactivity, obesity, and cardiovascular mortality might be exaggerated in patients with HC. More data are needed on exercise in those with HC to strike a balance between acute risks and the long-term health benefits of exercise.

Effects of emotional response on adherence to antihypertensive medication and blood pressure improvement

Background. Developing interventions to improve medication adherence may depend upon discovery of novel behavioral risk factors for nonadherence. Objective. Explore the effects of emotional response (ER) on adherence to antihypertensive medication and on systolic blood pressure (SBP) improvement. Design. We studied 101 adults with diabetes and hypertension. The primary outcome, 90-day “percentage of days covered” adherence score, was determined from pharmacy refill records. The secondary outcome was change in SBP over 90 days. ER was classified as positive, negative, or neutral. Results. Average adherence was 71.6% (SD 31.4%), and negative and positive ER were endorsed by 25% and 9% of subjects, respectively. Gender moderated the effect of positive or negative versus neutral ER on adherence (interaction P = 0.003); regardless of gender, negative and positive ER were associated with similarly high and low adherence, respectively, but males endorsing neutral ER had significantly higher adherence than their female counterparts (85.6% versus 57.1%, F value = 15.3, P = 0.0002). Adherence mediated ER's effect on SBP improvement: among participants with negative, but not positive or neutral, ER, increasing adherence and SBP improvement were correlated (Spearman's r = 0.49, P = 0.02). Conclusions. Negative, but not positive or neutral, ER predicted better medication adherence and a correlation between medication adherence and improvement in SBP.

Physical activity, cardiorespiratory fitness, and exercise training in primary and secondary coronary prevention

Substantial data have established that higher levels of physical activity (PA), participating in exercise training (ET), and higher overall cardiorespiratory fitness (CRF) provide considerable protection in the primary and secondary prevention of coronary heart disease (CHD). This review surveys data from epidemiological and prospective ET studies supporting the favorable impact of PA, ET, and CRF in primary CHD prevention. Clearly, cardiac rehabilitation and ET (CRET) programs have been underutilized for patients with CHD, particularly considering the effect of CRET on CHD risk factors, including CRF, obesity indices, fat distribution, plasma lipids, inflammation, and psychological distress, as well as overall morbidity and mortality. These data strongly support the routine referral of patients with CHD to CRET programs and that patients should be vigorously encouraged to attend CRET following major CHD events.

Gender differences in the associations among body mass index, weight loss, exercise, and drinking among college students

OBJECTIVE

To explore gender differences regarding weight management behaviors of college drinkers.

PARTICIPANTS

Nationally representative sample of college students from the fall 2008 American College Health Association's National College Health Assessment II (N = 26,062 students).

METHODS

Structural equation modeling was used to examine potential gender differences in associations among exercise, weight loss behaviors, and alcohol use.

RESULTS

Critical ratio tests revealed that associations between exercise and weight loss behaviors were more strongly correlated among females as compared with males. For females, there was a small negative association between exercise and drinking behaviors; in contrast, for males, there was a positive relationship between exercise and alcohol use. Weight loss behaviors were positively associated with drinking for both female and male students; however, the association was significantly stronger for females.

CONCLUSIONS

This investigation furthers previous research on drunkorexia and also sheds additional light on the gender-based differences in weight management behaviors of drinkers.

Measuring Free-Living Energy Expenditure and Physical Activity with Triaxial Accelerometry

OBJECTIVE

To investigate the ability of a newly developed triaxial accelerometer to predict total energy expenditure (EE) (TEE) and activity-related EE (AEE) in free-living conditions.

RESEARCH METHODS AND PROCEDURES

Subjects were 29 healthy subjects between the ages of 18 and 40. The Triaxial Accelerometer for Movement Registration (Tracmor) was worn for 15 consecutive days. Tracmor output was defined as activity counts per day (ACD) for the sum of all three axes or each axis separately (ACD-X, ACD-Y, ACD-Z). TEE was measured with the doubly labeled water technique. Sleeping metabolic rate (SMR) was measured during an overnight stay in a respiration chamber. The physical activity level was calculated as TEE x SMR(-1), and AEE was calculated as [(0.9 x TEE) - SMR]. Body composition was calculated from body weight, body volume, and total body water using Siri's three-compartment model.

RESULTS

Age, height, body mass, and ACD explained 83% of the variation in TEE [standard error of estimate (SEE) = 1.00 MJ/d] and 81% of the variation in AEE (SEE = 0.70 MJ/d). The partial correlations for ACD were 0.73 (p < 0.001) and 0.79 (p < 0.001) with TEE and AEE, respectively. When data on SMR or body composition were used with ACD, the explained variation in TEE was 90% (SEE = 0.74 and 0.77 MJ/d, respectively). The increase in the explained variation using three axes instead of one axis (vertical) was 5% (p < 0.05).

DISCUSSION

The correlations between Tracmor output and EE measures are the highest reported so far. To measure daily life activities, the use of triaxial accelerometry seems beneficial to uniaxial.

Seasonal variation in accelerometer-determined sedentary behaviour and physical activity in children: a review

AIM

To undertake a review of the methods and findings of published research evaluating the influence of season on accelerometer-determined sedentary behaviour (SB) and physical activity (PA) in children.

METHODS

A literature search was carried out using PubMed, Embase, Medline and Web of Science up to, and including, June 2011. The search strategy focused on four key elements: children, SB or PA, season and accelerometer. Articles were eligible for inclusion if they were published in English, included healthy study participants aged ≤ 18 years, reported at least one outcome variable derived from accelerometer-determined measurements, and compared SB or PA between two or more seasons, or controlled for season of measurement. Eligible papers were reviewed and evidence tables compiled reporting on publication year, country studied, study recruitment, consent rate, sample descriptives, study design, accelerometer protocol, valid accelerometer data receipt, season definition, statistical methods and key findings.

RESULTS

Sixteen of 819 articles were eligible for inclusion: children aged two to five years, six to twelve, or six to 18 years were included in five, six and five articles respectively. Six articles were from the UK, six from other European countries, three from the USA and one from New Zealand. Study sample sizes ranged from 64 to 5595. PA was reported in all articles but SB in only three. Only four studies were longitudinal and none of these reported SB. Seasonal variation in PA was reported in all UK studies, being highest in summer and lowest in winter. In four non-UK studies seasonal variation in PA was not found. Findings were inconclusive for SB.

CONCLUSION

There is sufficient evidence to support public health interventions aimed at increasing PA during winter in UK children. No conclusions can be drawn regarding the effect of season on children's SB reflecting few studies of small sample size, lack of repeat measures, incomparable definitions of season and inconsistent accelerometer protocols. Future research should determine factors that drive seasonal patterns in PA and SB in children such as age, sex, and geographic and climatic setting to inform interventions and target populations.

Advances in physical activity monitoring and lifestyle interventions in obesity: a review

Obesity represents a strong risk factor for developing chronic diseases. Strategies for disease prevention often promote lifestyle changes encouraging participation in physical activity. However, determining what amount of physical activity is necessary for achieving specific health benefits has been hampered by the lack of accurate instruments for monitoring physical activity and the related physiological outcomes. This review aims at presenting recent advances in activity-monitoring technology and their application to support interventions for health promotion. Activity monitors have evolved from step counters and measuring devices of physical activity duration and intensity to more advanced systems providing quantitative and qualitative information on the individuals' activity behavior. Correspondingly, methods to predict activity-related energy expenditure using bodily acceleration and subjects characteristics have advanced from linear regression to innovative algorithms capable of determining physical activity types and the related metabolic costs. These novel techniques can monitor modes of sedentary behavior as well as the engagement in specific activity types that helps to evaluate the effectiveness of lifestyle interventions. In conclusion, advances in activity monitoring have the potential to support the design of response-dependent physical activity recommendations that are needed to generate effective and personalized lifestyle interventions for health promotion.

The usefulness of an accelerometer for monitoring total energy expenditure and its clinical application for predicting body weight changes in type 2 diabetic korean women

BACKGROUND

The purpose of this study was to evaluate the usefulness of an accelerometer in predicting body weight (BW) change during a lifestyle intervention and to find out whether exercise or overall physical activity is associated with change in insulin sensitivity and body composition.

METHODS

A total of 49 overweight (body mass index [BMI] ≥ 23 kg/m(2)) women with diabetes were enrolled and performed lifestyle intervention while monitoring BW, total energy expenditure (TEE) and physical activity energy expenditure (PAEE) using an accelerometer, and energy intake (EI) using a three-day dietary record at baseline and every 2 weeks for 12 weeks. We assessed body composition using bioimpedance analysis and compared the actual BW change to the predicted BW change, which was calculated from the energy deficit (ED) between EI and TEE (ED = EI-TEE).

RESULTS

Mean age was 57.2 years, duration of diabetes was 8.0 years, and BMI was 27.8 kg/m(2). There was no significant difference between EI and TEE at baseline. For 12 weeks, the ED was 474.0 kcal·day(-1), which was significantly correlated with BW change (-3.1 kg) (r = 0.725, P < 0.001). However, the actual BW change was 50% lower than the predicted BW change. Both TEE and PAEE correlated with change in K(ITT) (r = 0.334, P = 0.019; r = 0.358, P = 0.012, respectively), BMI (r = -0.395, P = 0.005; r = -0.347, P = 0.015, respectively), and fat mass (r = -0.383, P = 0.007; r = -0.395, P = 0.005, respectively), but only TEE correlated with fat free mass change (r = -0.314, P = 0.030).

CONCLUSION

The accelerometer appears to be a useful tool for measuring TEE under free-living conditions for both short- and long-term periods.

Sedentary behaviors increase risk of cardiovascular disease mortality in men

PURPOSE

The purpose of this study was to examine the relationship between two sedentary behaviors (riding in a car and watching TV) and cardiovascular disease (CVD) mortality in men in the Aerobics Center Longitudinal Study.

METHODS

Participants were 7744 men (20-89 yr) initially free of CVD who returned a mail-back survey during 1982. Time spent watching TV and time spent riding in a car were reported. Mortality data were ascertained through the National Death Index until December 31, 2003. Cox regression analysis quantified the association between sedentary behaviors (hours per week watching TV, hours per week riding in a car, and total hours per week in these two behaviors) and CVD mortality rates.

RESULTS

Three hundred and seventy-seven CVD deaths occurred during 21 yr of follow-up. After age adjustment, time riding in a car and combined time spent in these two sedentary behaviors were positively (P(trend) < 0.001) associated with CVD death. Men who reported >10 h x wk(-1) riding in a car or >23 h x wk(-1) of combined sedentary behavior had 82% and 64% greater risk of dying from CVD than those who reported <4 or <11 h x wk(-1), respectively. The pattern of the association did not materially change after multivariate adjustment. Regardless of the amount of sedentary activity reported by these men, being older, having normal weight, being normotensive, and being physically active were associated with a reduced risk of CVD death.

CONCLUSION

In men, riding in a car and combined time spent in these two sedentary behaviors were significant CVD mortality predictors. In addition, high levels of physical activity were related to notably lower rates of CVD death even in the presence of high levels of sedentary behavior. Health promotion efforts targeting physically inactive men should emphasize both reducing sedentary activity and increasing regular physical activity for optimal cardiovascular health.

Physical activity and mortality risk in the Japanese elderly: a cohort study

BACKGROUND

Physical activity recommendations for older adults with poor health needs to be understood.

PURPOSE

This study aims to examine the association between the frequency of physical activity and mortality among a sample of elderly subjects, most of whom were under treatment for pre-existing disease.

METHODS

Data on the frequency of leisure-time physical activity, walking for transportation, and non-exercise physical activity were obtained from a population-based cohort study in Shizuoka, Japan. Of the randomly selected 22,200 residents aged 65-84 years, 10,385 subjects were followed from 1999 to 2006 and analyzed. Hazard ratios (HRs) and 95% CIs were obtained for all-cause; cardiovascular disease (CVD); and cancer mortality, after adjusting for covariates such as pre-existing disease(s). A subgroup analysis that was restricted to subjects under treatment for pre-existing disease(s) at baseline was further conducted. Data were collected between 1999 and 2006, and all analyses were conducted in 2008 and 2009.

RESULTS

Every physical activity was associated with a reduced risk of all-cause and CVD mortality, among not only the total sample but even those under treatment. The HRs for CVD mortality among participants with 5 or more days of non-exercise physical activity per week for the total sample and those with pre-existing disease(s) were 0.38 (95% CI=0.22, 0.55) and 0.35 (95% CI=0.24, 0.52), respectively, compared with no non-exercise physical activity. The association between physical activity and cancer mortality was not clear.

CONCLUSIONS

This study suggests a protective effect of physical activity on all-cause and CVD mortality among Japanese elderly people with pre-existing disease.

Classifying household and locomotive activities using a triaxial accelerometer

The purpose of this study was to develop a new algorithm for classifying physical activity into either locomotive or household activities using a triaxial accelerometer. Sixty-six volunteers (31 men and 35 women) participated in this study and were separated randomly into validation and cross-validation groups. All subjects performed 12 physical activities (personal computer work, laundry, dishwashing, moving a small load, vacuuming, slow walking, normal walking, brisk walking, normal walking while carrying a bag, jogging, ascending stairs and descending stairs) while wearing a triaxial accelerometer in a controlled laboratory setting. Each of the three signals from the triaxial accelerometer was passed through a second-order Butterworth high-pass filter to remove the gravitational acceleration component from the signal. The cut-off frequency was set at 0.7 Hz based on frequency analysis of the movements conducted. The ratios of unfiltered to filtered total acceleration (TAU/TAF) and filtered vertical to horizontal acceleration (VAF/HAF) were calculated to determine the cut-off value for classification of household and locomotive activities. When the TAU/TAF discrimination cut-off value derived from the validation group was applied to the cross-validation group, the average percentage of correct discrimination was 98.7%. When the VAF/HAF value similarly derived was applied to the cross-validation group, there was relatively high accuracy but the lowest percentage of correct discrimination was 63.6% (moving a small load). These findings suggest that our new algorithm using the TAU/TAF cut-off value can accurately classify household and locomotive activities.

Socio-demographic and perceived environmental correlates of walking in Portuguese adults--a multilevel analysis

Several studies have identified associations between walking levels and socio-demographic and environmental variables. The aim of the present study was to describe walking patterns and examine associations between socio-demographic characteristics and perceived environmental attributes with walking among adults living in the Azorean Archipelago (Portugal). In all, 7330 adult participants (4104 women), aged 38.1 +/- 9.3 years, of the 2004 Azorean Physical Activity and Health Study answered the Environmental Module and the short version of the International Physical Activity Questionnaire. Among the Azoreans, the environmental dimension "infrastructures, access to destinations, social environment and aesthetics" and moderate to vigorous physical activity were positively associated with walking levels; and smoking, sitting time and being married were negatively related, regardless of gender, age or education level. Through the cross-sectional nature of this study, our results suggest that targeted programs for Azoreans aimed to increase walking levels should consider that infrastructures, access to destinations, social environment and aesthetics seem to act synergistically and associate positively with walking behaviour.

Sports activity and risk of type 2 diabetes in Chinese

An association between physical inactivity and obesity risk has been established. However, the relationship between sports activity and the risk of diabetes among Chinese populations is still unclear. We prospectively investigated the association between sports activity and incidence of type 2 diabetes in a Chinese population. Habitual physical activity in the presumed last year was obtained from a questionnaire developed by Baecke and colleagues. During a median 9.02-year follow-up period among the 1936 participants with complete questionnaire data, 312 participants developed diabetes. After adjusting for age, gender and body mass index, the relative risk (RR) of diabetes according to quartiles of sports activity were 0.86, 0.71 and 0.72 (95% Confidence Interval [CI], 0.52-0.99, P for trend, 0.048). Participants with the highest quartiles of sports activity had a significantly lower risk than the participants with the lowest quartiles among the obese group (multivariate RR, 0.61, 95% CI, 0.41-0.92, P for trend=0.018). Furthermore, the RRs of diabetes were 2.24 (95% CI, 1.58-3.19) for participants who were obese and sedentary, compared with those who were of a healthy weight and participated actively in sports. The findings suggest a significant inverse association between sports activity and incidence of type 2 diabetes in middle to older-aged Chinese individuals.

Survey of cardiovascular risk factors in overweight and obese patients (SCOOP study) six-month changes in risk factor levels and cardiovascular risk

BACKGROUND

Obesity is considered a major threat to health worldwide, and its treatment is difficult. The SCOOP project is aimed at describing the effects of treating obesity in everyday clinical practice, following a standard protocol of weight reduction.

METHODS

A total of 2472 obese or overweight men and women (with a body mass index of 27 units or more), aged between 35 and 74, were enrolled in different clinical facilities. Treatment included a 25% average reduction in caloric intake and a recommendation to take a brisk walk for at least 150 min per week. After 6 months, a second survey was then carried out.

RESULTS

At the entry examination, patients exhibited high levels of most cardiovascular risk factors and estimated cardiovascular risks, and a high prevalence of cardiovascular diseases (14.1% in men; 6.3% in women), diabetes (30.5% in men; 25.2% in women) and metabolic syndrome (25.6% in men; 22.8% in women). After 6 months, 69% of all enrolled patients reported for a final examination. Levels of all cardiovascular risk factors were significantly reduced, including estimated cardiovascular risks (-20.4% in men and -12.6% in women). A targeted 10% reduction in body weight was achieved by 19% of patients. Changes in weight and cardiovascular risk factors were highly correlated with the self-reported compliance to prescriptions, and graded with the observed weight reduction. Benefits should be lowered by 30% if it is assumed that the patients who did not show up at the follow-up did not change their characteristics.

CONCLUSION

Short term positive effects of treatment of obesity can be obtained in everyday clinical practice using a simple protocol.

Endurance Training in the Spontaneously Hypertensive Rat

The effect of endurance training (swimming 90 min/d for 5 days a week for 60 days) on cardiac hypertrophy was investigated in the spontaneously hypertensive rat (SHR). Sedentary SHRs (SHR-Cs) and normotensive Wistar rats were used as controls. Exercise training enhanced myocardial hypertrophy assessed by left ventricular weight/tibial length (228±7 versus 251±5 mg/cm in SHR-Cs and exercised SHRs [SHR-Es], respectively). Myocyte cross-sectional area increased ≈40%, collagen volume fraction decreased ≈50%, and capillary density increased ≈45% in SHR-Es compared with SHR-Cs. The mRNA abundance of atrial natriuretic factor and myosin light chain 2 was decreased by the swimming routine (100±19% versus 41±10% and 100±8% versus 61±9% for atrial natriuretic factor and myosin light chain 2 in SHR-Cs and SHR-Es, respectively). The expression of sarcoplasmic reticulum Ca 2+ pump was significantly augmented, whereas that of Na + /Ca 2+ exchanger was unchanged (93±7% versus 167±8% and 158±13% versus 157±7%, sarcoplasmic reticulum Ca 2+ pump and Na + /Ca 2+ exchanger in SHR-Cs and SHR-Es, respectively; P <0.05). Endurance training inhibited apoptosis, as reflected by a decrease in caspase 3 activation and poly(ADP-ribose) polymerase-1 cleavage, and normalized calcineurin activity without inducing significant changes in the phosphatidylinositol 3-kinase/Akt pathway. The swimming routine improved midventricular shortening determined by echocardiography (32.4±0.9% versus 36.9±1.1% in SHR-Cs and SHR-Es, respectively; P <0.05) and decreased the left ventricular free wall thickness/left ventricular cavity radius toward an eccentric model of cardiac hypertrophy (0.59±0.02 versus 0.53±0.01 in SHR-Cs and SHR-Es, respectively; P <0.05). In conclusion, we present data demonstrating the effectiveness of endurance training to convert pathological into physiological hypertrophy improving cardiac performance. The reduction of myocardial fibrosis and calcineurin activity plus the increase in capillary density represent factors to be considered in determining this beneficial effect.

Obesity, leanness, and mortality: effect modification by physical activity in men and women

The 13-year mortality from BMI, body fat (BF), and fat-free mass (FFM) was examined among active and sedentary adults. In total, 2,819 men and women aged 35-65 years in 1987/1988, participating in the Danish MONICA project, were included, and followed for 13.6 years for total mortality. In men, physical activity modified the health hazard of both a high and a low BMI, and the U-shaped association disappeared among the active (hazard ratio (HR) = 0.86, CI: 0.72-1.02). Among active men, FFM was inversely related to mortality (HR = 0.55, 95% CI: 0.40-0.77) whereas a direct positive trend was seen for BF. Among women, physical activity modified association between BMI and mortality, but the U-shaped association remained among the active. Among women, no significant associations were found between either BF or FFM and total mortality. All effects were independent of waist- and hip-circumferences. In conclusion, among men, physical activity may play an important role for the prevention of early mortality beyond its direct effects, by modifying the health hazard of both a high and a low BMI, and by lowering the risk associated with a high BF or a low FFM. Among women physical activity lowers mortality, but an effect-modifying potential of physical activity on associations between BMI or body composition could not be identified.

Association of physical activity with all-cause and cardiovascular mortality: a systematic review and meta-analysis

BACKGROUND

Over the past several decades, numerous large cohort studies have attempted to quantify the protective effect of physical activity on cardiovascular and all-cause mortality. The aim of the authors' review was to provide an up-to-date overview of the study results.

METHODS

In a systematic MEDLINE search conducted in May 2007, the authors included cohort studies that assessed the primary preventive impact of physical activity on all-cause and cardiovascular mortality. The authors reported risk reductions on the basis of comparison between the least active and the most active population subgroups, with the least active population subgroup as the reference group. Random-effect models were used for meta-analysis.

RESULTS

A total of 33 studies with 883,372 participants were included. Follow-up ranged from 4 years to over 20 years. The majority of studies reported significant risk reductions for physically active participants. Concerning cardiovascular mortality, physical activity was associated with a risk reduction of 35% (95% confidence interval, 30-40%). All-cause mortality was reduced by 33% (95% confidence interval, 28-37%). Studies that used patient questionnaires to assess physical activity reported lower risk reductions than studies that used more objective measures of fitness.

CONCLUSIONS

Physical activity is associated with a marked decrease in cardiovascular and all-cause mortality in both men and women, even after adjusting for other relevant risk factors.

Effect of physical activity on heart rate variability in normal weight, overweight and obese subjects: results from the SAPALDIA study

Many studies have demonstrated an association of both a sedentary lifestyle and a high body mass index (BMI) with greater risk for cardiovascular disease. Within the prospective SAPALDIA cohort (Swiss cohort Study on Air Pollution and Lung Diseases in Adults), we investigated whether regular exercise was protective against reduced heart rate variability (HRV), a clinically relevant predictor of cardiovascular morbidity and mortality, and whether adverse effects of obesity and weight gain on HRV were modified by regular exercise. Twenty-four-hour electrocardiograms were recorded in 1,712 randomly selected SAPALDIA participants aged >or=50, for whom BMI was assessed in the years 1991 and 2001-2003. Other examinations included an interview investigating health status (especially respiratory and cardiovascular health and health relevant behaviours including physical activity) and measurements of blood pressure, body height and weight. The association between regular physical activity and HRV and interactions with BMI and BMI change was assessed in multivariable linear regression analyses. Compared to sedentary obese subjects, SDNN (standard deviation of all RR intervals) was 14% (95% CI: 8-20%) higher in sedentary normal weight subjects; 19% (CI: 12-27%) higher in normal weight subjects exercising regularly >or=2 h/week; and 19% (CI: 11-28%) higher in obese subjects exercising regularly >or=2 h/week. Compared with sedentary subjects who gained weight, those who gained weight but did exercise regularly had a 13% higher SDNN (CI: 7-20%). Regular physical exercise has strong beneficial effects on cardiac autonomic nervous function and thus appears to offset the negative effect of obesity on HRV.

Physical activity and perceived environmental attributes in a sample of Portuguese adults: results from the Azorean Physical Activity and Health study

OBJECTIVES

The aim of the present study was to determine whether the relation of perceived neighbourhood attributes to reported Physical Activity (PA) levels in Azorean adults varied by gender and body mass index (BMI).

METHODS

7330 adult participants (4104 women), aged 38.1+/-9.3 years, from the 2004 Azorean Physical Activity and Health Study. They answered the Environmental Module and the short version of the International Physical Activity Questionnaire (IPAQ). Height and weight were self-reported.

RESULTS

After adjustments for age, BMI, education level and island of residence, the dimension Infrastructures, Access to destinations, Social environment and Aesthetics was positively associated with moderate PA level and Health-Enhancing Physical Activity (HEPA) level, only in women. When participants were categorized by BMI status, the same dimension was a significant predictor for moderate PA level in normal weight men and women, and for HEPA level only in overweight/obese women, after controlling for age, education level and island of residence.

CONCLUSIONS

The dimension Infrastructures, Access to destinations, Social environment and Aesthetics was predictors of higher PA levels in Azorean adults. Targeted programs for Azoreans to increase PA levels should consider that this set of environmental features seem to act synergistically and are positively associated with PA.

Exercise training delays cardiac dysfunction and prevents calcium handling abnormalities in sympathetic hyperactivity-induced heart failure mice

Exercise training (ET) is a coadjuvant therapy in preventive cardiology. It delays cardiac dysfunction and exercise intolerance in heart failure (HF); however, the molecular mechanisms underlying its cardioprotection are poorly understood. We tested the hypothesis that ET would prevent Ca2+ handling abnormalities and ventricular dysfunction in sympathetic hyperactivity-induced HF mice. A cohort of male wild-type (WT) and congenic α2A/α2C-adrenoceptor knockout (α2A/α2CARKO) mice with C57BL6/J genetic background (3–5 mo of age) were randomly assigned into untrained and exercise-trained groups. ET consisted of 8-wk swimming session, 60 min, 5 days/wk. Fractional shortening (FS) was assessed by two-dimensional guided M-mode echocardiography. The protein expression of ryanodine receptor (RyR), phospho-Ser2809-RyR, sarcoplasmic reticulum Ca2+ ATPase (SERCA2), Na+/Ca2+ exchanger (NCX), phospholamban (PLN), phospho-Ser16-PLN, and phospho-Thr17-PLN were analyzed by Western blotting. At 3 mo of age, no significant difference in FS and exercise tolerance was observed between WT and α2A/α2CARKO mice. At 5 mo, when cardiac dysfunction is associated with lung edema and increased plasma norepinephrine levels, α2A/α2CARKO mice presented reduced FS paralleled by decreased SERCA2 (26%) and NCX (34%). Conversely, α2A/α2CARKO mice displayed increased phospho-Ser16-PLN (76%) and phospho-Ser2809-RyR (49%). ET in α2A/α2CARKO mice prevented exercise intolerance, ventricular dysfunction, and decreased plasma norepinephrine. ET significantly increased the expression of SERCA2 (58%) and phospho-Ser16-PLN (30%) while it restored the expression of phospho-Ser2809-RyR to WT levels. Collectively, we provide evidence that improved net balance of Ca2+ handling proteins paralleled by a decreased sympathetic activity on ET are, at least in part, compensatory mechanisms against deteriorating ventricular function in HF.

Low physical activity and obesity: causes of chronic disease or simply predictors?

BACKGROUND AND PURPOSE

Many studies have shown associations between risk of morbidity and mortality with both obesity and low physical activity (PA), but association does not imply causality. Moreover, there is an inverse relationship between PA and obesity; therefore, controlling for one of these factors when investigating the risk associated with the other is essential. The purpose of this review is to determine whether low PA and obesity actually cause metabolic dysfunction and chronic disease, especially type 2 diabetes (T2D), rather than simply operating as predictors or markers.

METHODS

The case for causality is strengthened if the following two conditions are satisfied: first, that significant associations between obesity or low PA and risk persist after controlling appropriately; and second, that the physiological mechanisms by which obesity or low PA may exert a causal effect are clearly established. The studies examined include those that have used cardiorespiratory (CR) fitness as a surrogate measure for PA, thus also providing evidence for low CR fitness as an independent risk factor in its own right.

RESULTS AND CONCLUSIONS

Low PA and poor CR fitness are independent predictors of mortality related to type 2 diabetes and chronic disease in general. Together with well-demonstrated mechanisms, there is strong evidence that low PA and low CR fitness are direct, independent causes of metabolic dysfunction and type 2 diabetes. Despite some reports to the contrary, there is evidence that both general and visceral obesity are predictors of mortality and morbidity after controlling for PA. However, in the absence of established mechanisms, evidence is insufficient to conclude that either general or visceral obesity is a direct, independent cause of metabolic dysfunction or type 2 diabetes.

Physical activity assessment with accelerometers: an evaluation against doubly labeled water

This review focuses on the ability of different accelerometers to assess daily physical activity as compared with the doubly labeled water (DLW) technique, which is considered the gold standard for measuring energy expenditure under free-living conditions. The PubMed Central database (U.S. NIH free digital archive of biomedical and life sciences journal literature) was searched using the following key words: doubly or double labeled or labeled water in combination with accelerometer, accelerometry, motion sensor, or activity monitor. In total, 41 articles were identified, and screening the articles' references resulted in one extra article. Of these, 28 contained sufficient and new data. Eight different accelerometers were identified: 3 uniaxial (the Lifecorder, the Caltrac, and the CSA/MTI/Actigraph), one biaxial (the Actiwatch AW16), 2 triaxial (the Tritrac-R3D and the Tracmor), one device based on two position sensors and two motion sensors (ActiReg), and the foot-ground contact pedometer. Many studies showed poor results. Only a few mentioned partial correlations for accelerometer counts or the increase in R(2) caused by the accelerometer. The correlation between the two methods was often driven by subject characteristics such as body weight. In addition, standard errors or limits of agreement were often large or not presented. The CSA/MTI/Actigraph and the Tracmor were the two most extensively validated accelerometers. The best results were found for the Tracmor; however, this accelerometer is not yet commercially available. Of those commercially available, only the CSA/MTI/Actigraph has been proven to correlate reasonably with DLW-derived energy expenditure.

Body mass index-independent effect of fitness and physical activity for all-cause mortality

Both obesity and physical inactivity are associated with chronic disease and premature mortality. A review of the literature has shown that both objectively measured level of physical fitness and self-reported physical activity have a prognostic value for all-cause mortality, independently of body mass index. Furthermore, there is evidence for a dose-response effect of physical activity. In conclusion, regular exercise has health-promoting effects, which are beyond its effect on weight control.

The relative influences of fitness and fatness on inflammatory factors

OBJECTIVE

Inflammatory processes contribute to disease pathways and may be affected by behavioral lifestyle factors. The relative contributions of fatness and cardiorespiratory fitness to inflammatory factors remain unclear. The present review examines the hypothesis that the association between fitness and inflammatory factors is independent of fatness.

METHODS

Data were examined from 40 observational studies on the association between fitness/physical activity and inflammatory factors after making statistical adjustment for measures of fatness, and from 12 randomized controlled trials that considered the impact of improved fitness and weight loss.

RESULTS

Two thirds of the observational studies report an inverse relationship between inflammatory factors and fitness after adjustment for fatness. Evidence from randomized controlled trials does not consistently support the hypothesis. Inconsistencies in the literature may be related to various factors such as age, gender, and disease status.

CONCLUSIONS

Both fitness and fatness appear to contribute to inflammatory factors, although it is unclear whether fatness is a mediator or if both fitness and fatness share the same causal pathways. Lifestyle interventions for primary prevention in the general public should therefore focus on both increasing physical activity and the prevention of excess adiposity, although the optimal exercise dose and body composition for preventing chronic inflammatory processes is not well established.