Current knowledge on the prognosis of metabolically healthy but obese phenotype is limited due to the exclusive use of the body mass index to define obesity and the lack of information on cardiorespiratory fitness. We aimed to test the following hypotheses: (i) metabolically healthy but obese individuals have a higher fitness level than their metabolically abnormal and obese peers; (ii) after accounting for fitness, metabolically healthy but obese phenotype is a benign condition, in terms of cardiovascular disease and mortality.
Methods and results
Fitness was assessed by a maximal exercise test on a treadmill and body fat per cent (BF%) by hydrostatic weighing or skinfolds (obesity = BF% ≥25 or ≥30%, men or women, respectively) in 43 265 adults (24.3% women). Metabolically healthy was considered if meeting 0 or 1 of the criteria for metabolic syndrome. Metabolically healthy but obese participants (46% of the obese subsample) had a better fitness than metabolically abnormal obese participants (P < 0.001). When adjusting for fitness and other confounders, metabolically healthy but obese individuals had lower risk (30–50%, estimated by hazard ratios) of all-cause mortality, non-fatal and fatal cardiovascular disease, and cancer mortality than their metabolically unhealthy obese peers; while no significant differences were observed between metabolically healthy but obese and metabolically healthy normal-fat participants.
(i) Higher fitness should be considered a characteristic of metabolically healthy but obese phenotype. (ii) Once fitness is accounted for, the metabolically healthy but obese phenotype is a benign condition, with a better prognosis for mortality and morbidity than metabolically abnormal obese individuals.
Cardiovascular diseases; Heart diseases; Metabolic syndrome; Mortality; Obesity; Physical fitness
There is evidence that physical activity may reduce the risk of developing Alzheimer’s disease and dementia. However, few reports have examined the physical activity-dementia association with objective measures of physical activity. Cardiorespiratory fitness (hereafter called fitness) is an objective reproducible measure of recent physical activity habits.
We sought to determine whether fitness is associated with lower risk for dementia mortality in women and men.
We followed 14,811 women and 45,078 men, ages 20-88 at baseline, for an average of 17 years. All participants completed a preventive health examination at the Cooper Clinic in Dallas, Texas during 1970-2001. Fitness was measured with a maximal treadmill exercise test, with results expressed in maximal metabolic equivalents (METs). The National Death Index identified deaths through 2003. Cox proportional hazards models were used to examine the association between baseline fitness and dementia mortality, adjusting for age, sex, examination year, body mass index, smoking, alcohol use, abnormal ECGs, and health status.
There were 164 deaths with dementia listed as the cause during 1,012,125 person-years of exposure. Each 1-MET increase in fitness was associated with a 14% lower adjusted risk of dementia mortality (95% confidence interval, CI 6%-22%). With fitness expressed in tertiles, adjusted hazard ratios (HRs) for those in the middle and high fitness groups suggest their risk of dementia mortality was less than half that of those in the lowest fitness group (respectively: HR 0.44, CI 0.26-0.74; HR 0.49, CI 0.26-0.90).
Greater fitness was associated with lower risk of mortality from dementia in a large cohort of men and women.
physical fitness; cognitive function; Alzheimer’s disease; vascular dementia; metabolic equivalents (METs)
We assessed the effects of the four newly defined American Heart Association (AHA) lifestyle factors on mortality by examining the associated population attributable fractions (PAFs) of these factors.
Slightly modified AHA cardiovascular health factors (smoking, BMI, cardiorespiratory fitness, and diet) were measured among 11,240 (24% women) participants from the Aerobics Center Longitudinal Study between 1987 and 1999. The cohort was followed to December 31, 2003 or death. PAFs were calculated as the proportionate reduction in death attributable to identified risk factors.
During an average 12 years of follow-up, 268 deaths occurred. Low fitness had the highest PAFs at the 5th, 10th, and 15th year of follow-up, respectively: 6.6%, 6.4%, and 5.5%. Current smokers had the second highest PAFs at the 5th, 10th, and 15th year of follow-up, respectively: 5.4%, 5.2%, and 5.0%. Additional adjusting for other confounders in the model did not change the above associations. The PAFs for overweight or obesity and unhealthy diet were not significant in the current analyses.
Assuming a causal relationship between smoking, low fitness and mortality, avoidance of both would have prevented 13% of the deaths in the current population. Preventive interventions to increase physical activity and stop smoking would most likely promote longevity.
Physical inactivity is an important modifiable risk factor for non-communicable disease. The degree to which physical activity affects the life expectancy of Americans is unknown. This study estimated the potential years of life gained due to leisure-time physical activity across the adult lifespan in the United States.
Data from the National Health and Nutrition Examination Survey (2007–2010), National Health Interview Study mortality linkage (1990–2006), and US Life Tables (2006) were used to estimate and compare life expectancy at each age of adult life for inactive (no moderate-to-vigorous physical activity), somewhat active (some moderate-to-vigorous activity but <500 metabolic equivalent min/week) and active (≥500 metabolic equivalent min/week of moderate-to-vigorous activity) adults. Analyses were conducted in 2012.
Somewhat active and active non-Hispanic white men had a life expectancy at age 20 that was around 2.4 years longer than the inactive men; this life expectancy advantage was 1.2 years at age 80. Similar observations were made in non-Hispanic white women, with a higher life expectancy within the active category of 3.0 years at age 20 and 1.6 years at age 80. In non-Hispanic black women, as many as 5.5 potential years of life were gained due to physical activity. Significant increases in longevity were also observed within somewhat active and active non-Hispanic black men; however, among Hispanics the years of life gained estimates were more variable and not significantly different from 0 years gained.
Leisure-time physical activity is associated with increases in longevity in the United States.
Exercise training reduces adiposity and risk of cardiovascular disease. However, the combined effects of habitual free-living physical activity and aerobic training on waist circumference, weight, fitness, and blood pressure in postmenopausal women are unknown.
To evaluate the effects of habitual physical activity levels during aerobic training on weight, waist circumference, fitness, and blood pressure.
Secondary analysis of an RCT. Original data collected April 2001 to June 2005 and analyzed in 2012.
Postmenopausal women in a supervised exercise trial.
Women (n=325) were randomized to 4, 8, or 12 kcal per kg per week of aerobic training or a control group for 6 months. All outcome measures were collected at baseline and follow-up. Changes in dependent variables within each training group were evaluated across tertiles of pedometer-determined habitual physical activity outside exercise training sessions.
Main outcome measures
Changes in waist circumference and weight.
Reductions in waist circumference were significantly greater with higher steps/day accumulated outside exercise training compared to lower levels in the 4 (high: −4.8 cm vs low: −1.4 cm, p=0.03); 8 (high: −4.2 cm vs low: −0.4 cm, p=0.03), and 12 kcal per kg per week groups (high: −4.1 cm vs low: −0.7 cm, p=0.05). For all groups, p-trend < 0.03). A trend was observed for greater weight reduction with higher steps/day in the 4 kcal per kg per week group (p-trend= 0.04), but not for the other exercise doses. No effects were observed for blood pressure or fitness measures (all p>0.05).
In postmenopausal women, higher habitual physical activity while participating in aerobic training was associated with greater reductions in central adiposity, and was supportive of weight loss compared to lower levels.
Non-exercise algorithms are cost-effective methods to estimate cardiorespiratory fitness (CRF) in healthcare settings. The limitation of current non-exercise models is that they were developed with cross-sectional data.
To extend the non-exercise research by developing algorithms for men and women using longitudinal data on indicators available in healthcare settings.
The sample included 1325 women (aged 20–78 years) and 10,040 men (aged 20–86 years) who completed from two to 21 maximal treadmill tests between 1977 and 2005. The data were analyzed in 2011 and 2012. The dependent variable was CRF measured by treadmill test. The independent variables were age, body composition (percentage fat or BMI); waist circumference, self-reported physical activity; resting heart rate; and smoking behavior.
Linear mixed-models regression showed that all variables were independently related to CRF. There was a positive association between CRF and physical activity. Higher levels of body composition were linked to lower CRF. High resting heart rate and smoking resulted in lower estimates of CRF. The error estimates of the percentage fat algorithms were: women, 1.41 METs (95% CI=1.35, 1.47); and men, METs 1.54 (95% CI=1.51, 1.55). The BMI models were somewhat less accurate: women, METs 1.51 (95% CI=1.45, 1.58); and men, 1.66 METs (95% CI=1.63, 1.68).
These results showed that the CRF of women and men can be estimated from easily obtained health indicators. The longitudinal non-exercise algorithms provide models to accurately estimate CRF changes associated with aging and provide cost-effective algorithms to track CRF over time with health indicators available in healthcare settings.
Physical fitness is one of the strongest predictors of individual future health status. Together with cardiorespiratory fitness (CRF), muscular strength (MusS) has been increasingly recognized in the pathogenesis and prevention of chronic disease. We review the most recent literature on the effect of MusS in the development of cardiovascular disease (CVD), with special interest in elucidating its specific benefits beyond those from CRF and body composition. MusS has shown an independent protective effect on all-cause and cancer mortality in healthy middle-aged men, as well as in men with hypertension (HTN) and patients with heart failure. It has also been inversely associated with age-related weight and adiposity gains, risk of HTN, and prevalence and incidence of the metabolic syndrome. In children and adolescents, higher levels of muscular fitness have been inversely associated with insulin resistance, clustered cardiometabolic risk and inflammatory proteins. Generally, the influence of muscular fitness was weakened but remained protective after considering CRF. Also interestingly, higher levels of muscular fitness seems to some extent counteract the adverse cardiovascular profile of overweight and obese individuals. As many of the investigations have been conducted with non-Hispanic white men, it is important to examine how race/ethnicity and gender may affect these relationships. To conclude, most important effects of resistance training (RT) are also summarized, to better understand how higher levels of muscular fitness may result in a better cardiovascular prognosis and survival.
muscular strength; cardiorespiratory fitness; cardiovascular disease; resistance training
Methodological limitations compromise the validity of U.S. nutritional surveillance data and the empirical foundation for formulating dietary guidelines and public health policies.
Evaluate the validity of the National Health and Nutrition Examination Survey (NHANES) caloric intake data throughout its history, and examine trends in the validity of caloric intake estimates as the NHANES dietary measurement protocols evolved.
Validity of data from 28,993 men and 34,369 women, aged 20 to 74 years from NHANES I (1971–1974) through NHANES 2009–2010 was assessed by: calculating physiologically credible energy intake values as the ratio of reported energy intake (rEI) to estimated basal metabolic rate (BMR), and subtracting estimated total energy expenditure (TEE) from NHANES rEI to create ‘disparity values’.
Main Outcome Measures
1) Physiologically credible values expressed as the ratio rEI/BMR and 2) disparity values (rEI–TEE).
The historical rEI/BMR values for men and women were 1.31 and 1.19, (95% CI: 1.30–1.32 and 1.18–1.20), respectively. The historical disparity values for men and women were −281 and −365 kilocalorie-per-day, (95% CI: −299, −264 and −378, −351), respectively. These results are indicative of significant under-reporting. The greatest mean disparity values were −716 kcal/day and −856 kcal/day for obese (i.e., ≥30 kg/m2) men and women, respectively.
Across the 39-year history of the NHANES, EI data on the majority of respondents (67.3% of women and 58.7% of men) were not physiologically plausible. Improvements in measurement protocols after NHANES II led to small decreases in underreporting, artifactual increases in rEI, but only trivial increases in validity in subsequent surveys. The confluence of these results and other methodological limitations suggest that the ability to estimate population trends in caloric intake and generate empirically supported public policy relevant to diet-health relationships from U.S. nutritional surveillance is extremely limited.
Studies of physical activity and incidence of physician-diagnosed depression have been limited to a single estimate of self-reported physical activity exposure, despite follow-up periods lasting many years.
To examine longitudinal change in cardiorespiratory fitness, an objective marker of habitual physical activity, and incident depression complaints made to a physician.
Cardiorespiratory fitness assessed at four clinic visits between 1971 and 2006, each separated by an average of 2–3 years, was used to objectively measure cumulative physical activity exposure in cohorts of 7936 men and 1261 women, aged 20–85 years, from the Aerobics Center Longitudinal Study who did not complain of depression at their first clinic visit in 1971–2003. Data were analyzed in August 2010.
Across subsequent visits, there were 446 incident cases in men and 153 cases in women. After adjustment for age, time between visits, BMI at each visit, and fitness at Visit 1, each 1-minute decline in treadmill endurance (i.e., a decline in cardiorespiratory fitness of approximately 1 half-MET) between ages 51 and 55 years in men and ages 53 and 56 years in women, increased the odds of incident depression complaints by approximately 2% and 9.5%, respectively. The increased odds remained significant but were attenuated to 1.3% and 5.4% after further adjustment at each visit for smoking, alcohol use, chronic medical conditions, anxiety, and sleep problems.
Maintenance of cardiorespiratory fitness during late middle-age, when decline in fitness typically accelerates, helps protect against the onset of depression complaints made to a physician.
Emerging evidence suggests the adverse association between sedentary behaviour (SB) with physical and mental health, but few studies have investigated the relationship between volume of physical activity and psychological distress. The present study examined the independent and interactive associations of daily SB and weekly level of moderate to vigorous physical activity (MVPA) with psychological distress in a multi-ethnic Asian population.
De-identified data of 4,337 adults (18–79 years old) on sedentary behaviors, physical activity patterns, psychological distresses, and other relevant variables were obtained from the Singapore Ministry of Health’s 2010 National Health Survey. Psychological distress was assessed using General Health Questionnaire-12 (GHQ-12), whereas total daily SB and total weekly volume (MET/minutes) of MVPA were estimated using the Global Physical Activity Questionnaire version 2 (GPAQ v2). Multivariate logistic regression analyses were carried out to estimate the odds ratios (95% confidence intervals) of the independent and interactive relationships of SB and MVPA with prevalence of psychological distress.
The category of high SB was positively associated with increased odds (OR = 1.29, 1.04-1.59) for psychological distress, whereas the category of active was inversely associated with lower odds (OR = 0.73, 0.62-0.86) for psychological distress. Multivariate analyses for psychological distress by combined daily SB and weekly MVPA levels showed inverse associations between middle SB and active categories (OR = 0.58, 0.45 - 0.74) along with low SB and active categories (OR = 0.61, 0.47-0.80).
The present population-based cross-sectional study indicated that in the multi-ethnic Asian society of Singapore, a high level of SB was independently associated with psychological distress and meeting the recommended guidelines for physical activity along with ≤ 5 h/day of SB was associated with the lowest odds of psychological distress.
Sedentary behavior; Volume; Physical activity; Psychological distress; Singapore; Cross-sectional
Physical activity may protect against breast cancer. Few prospective studies have evaluated breast cancer mortality in relation to cardiorespiratory fitness, an objective marker of physiologic response to physical activity habits.
We examined the association between cardiorespiratory fitness and risk of death from breast cancer in the Aerobics Center Longitudinal Study. Women (N=14,811), aged 20 to 83 years with no prior breast cancer history, received a preventive medical examination at the Cooper Clinic in Dallas, TX, between 1970 and 2001. Mortality surveillance was completed through December 31, 2003. Cardiorespiratory fitness was quantified as maximal treadmill exercise test duration and was categorized for analysis as low (lowest 20% of exercise duration), moderate (middle 40%), and high (upper 40%). At baseline, all participants were able to complete the exercise test to at least 85% of their age-predicted maximal heart rate.
A total of 68 breast cancer deaths occurred during follow-up (mean=16 years). Age-adjusted breast cancer mortality rates per 10,000 woman-years were 4.4, 3.2, and 1.8 for low, moderate, and high cardiorespiratory fitness groups, respectively (trend P = 0.008). After further controlling for body mass index, smoking, drinking, chronic conditions, abnormal exercise electrocardiogram responses, family history of breast cancer, oral contraceptive use, and estrogen use, hazard ratios (95% CI) for breast cancer mortality across incremental cardiorespiratory fitness categories were 1.00 (referent), 0.67 (0.35–1.26), 0.45 (0.22–0.95); trend P = 0.04.
These results indicate that cardiorespiratory fitness is associated with a reduced risk of dying from breast cancer in women.
Epidemiology; Prevention; Death from breast cancer; Physical activity
We examined the associations between muscular strength, markers of overall and central adiposity and cancer mortality in men.
Prospective cohort study including 8,677 men aged 20-82 years followed from 1980 to 2003. Participants were enrolled in The Aerobics Centre Longitudinal Study, the Cooper Clinic in Dallas, Texas, U.S. Muscular strength was quantified by combining 1-repetition maximal measures for leg and bench presses. Adiposity was assessed by body mass index (BMI), percent body fat, and waist circumference.
Cancer death rates per 10,000 person-years adjusted for age and examination year were: 17.5, 11.0, and 10.3 across incremental thirds of muscular strength (P=0.001); 10.9, 13.4, and 20.1 across BMI groups of 18.5-24.9, 25.0-29.9, and ≥30kg/m2, respectively (P=0.008); 11.6 and 17.5 for normal (<25%) and high percent body fat (≥25%), respectively (P=0.006); and 12.2 and 16.7 for normal (≤102 cm) and high waist circumference (>102 cm), respectively (P=0.06). After adjusting for additional potential confounders, hazard ratios (95% confidence intervals) were 1.00 (referent), 0.65 (0.47-0.90), and 0.61 (0.44-0.85) across incremental thirds of muscular strength, respectively (P=0.003 for linear trend). Further adjustment for BMI, percent body fat, waist circumference, or cardiorespiratory fitness had little effect on the association. The associations of BMI, percent body fat, or waist circumference with cancer mortality did not persist after further adjusting for muscular strength (all P≥0.1).
Higher levels of muscular strength are associated with lower cancer mortality risk in men, independent of clinically established measures of overall and central adiposity, and other potential confounders.
Muscular strength; obesity; cancer; cardiorespiratory fitness; resistance exercise
We modeled the age-related trajectory of glucose and determined if cardiorespiratory fitness altered the trajectory in a cohort of men from the Aerobics Center Longitudinal Study.
10,092 men free of diagnosed diabetes, CVD, and cancer, aged 20 to 90 years, completed from 2 to 21 health examinations between 1977 and 2005. Cardiorespiratory fitness was measured by a maximal treadmill exercise test and normalized for age. The covariates included waist circumference, hypertension, elevated cholesterol, smoking behavior and physical activity.
Linear mixed models regression analysis showed that fasting glucose increased at a linear rate with aging. Glucose increased at a yearly rate of 0.17 mg/dL (95% confidence interval: 0.16, 0.19). Fitness had little influence on the aging glucose trajectory below age 35, but significantly influenced the trend after age 35 (P for interaction <0.001). The aging-related glucose increases in low fit men (0.25 mg/dL per year) was higher than average fit (0.15 mg/dL per year) and high fit (0.13 mg/dL per year) men.
The aging-related glucose increases in low fit men was nearly double that of high fit men. Our results may suggest that it is possible to delay the age-related glucose impairment through increasing one’s fitness.
Fasting glucose; aging; physical fitness
Strong evidence shows that physical inactivity increases the risk of many adverse health conditions, including the world’s major non-communicable diseases (NCDs) of coronary heart disease (CHD), type 2 diabetes, and breast and colon cancers, and shortens life expectancy. Because much of the world’s population is inactive, this presents a major public health problem. We aimed to quantify the impact of physical inactivity on these major NCDs by estimating how much disease could be averted if those inactive were to become active and to estimate gain in life expectancy, at the population level.
Using conservative assumptions, we calculated population attributable fractions (PAF) associated with physical inactivity for each of the major NCDs, by country, to estimate how much disease could be averted if physical inactivity were eliminated, and used life table analysis to estimate gains in life expectancy of the population.
Worldwide, we estimate that physical inactivity is responsible for 6% of the burden of disease from CHD (range: 3.2% in South-east Asia to 7.8% in the Eastern Mediterranean region); 7% of type 2 diabetes (3.9% to 9.6%), 10% of breast cancer (5.6% to 14.1%), and 10% of colon cancer (5.7% to 13.8%). Inactivity is responsible for 9% of premature mortality (5.1% to 12.5%), or >5.3 of the 57 million deaths that occurred worldwide in 2008. If inactivity were not eliminated, but decreased instead by 10% or 25%, >533,000 and >1.3 million deaths, respectively, may be averted each year. By eliminating physical inactivity, life expectancy of the world’s population is estimated to increase by 0.68 (0.41 to 0.95) years.
Physical inactivity has a major health impact on the world. Elimination of physical inactivity would remove between 6% and 10% of the major NCDs of CHD, type 2 diabetes, and breast and colon cancers, and increase life expectancy.
To determine if time spent in screen-based sedentary behavior is associated with change in cardiorespiratory fitness (CRF) levels in children from age 11 to 13, adjusting for vigorous physical activity (VPA).
Participants were children (n=2,097) enrolled in the control arm of the HEALTHY Study, who performed 20m shuttle run tests at ages 11 and 13. Self-reported screen time was used as a measure of sedentary behavior. Longitudinal quantile regression was used to model the influence of predictors on changes at the 10th, 25th, 50th, 75th and 90th shuttle run lap percentiles. Screen time (hrs/d) was the main predictor and adjustment was also made for VPA, body mass index and household education.
In boys, more screen time was associated with fewer shuttle run laps completed from age 11 to 13 at the 25th, 50th and 75th shuttle run lap percentiles; the strongest association was at the 75th shuttle run percentile (-0.57, 95% CI: -0.93 to -0.21). In girls, more screen time was associated with fewer shuttle run laps completed from age 11 to 13 at the 50th, 75th and 90th shuttle run lap percentiles; the strongest association was at the 90th shuttle run percentile (-0.65, -1.01 to -0.30). Borderline negative associations were found between screen time and shuttle run laps at the 10th shuttle run percentile in boys and girls (-0.28, -0.57 to 0.01 and -0.17, -0.41 to 0.06, respectively).
More screen time was associated with lower CRF from age 11 to 13, independent of VPA. However, the association was weakest at the lower tail of the CRF distribution.
aerobic; shuttle run; pacer; television; computer; longitudinal
Background. Prior studies suggest that weight satisfaction may preclude changes in behavior that lead to healthier weight among individuals who are overweight or obese. Objective. To gain a better understanding of complex relationships between weight satisfaction, weight-related health behaviors, and health outcomes. Design. Cross-sectional analysis of data from the Aerobics Center Longitudinal Study (ACLS). Participants. Large mixed-gender cohort of primarily white, middle-to-upper socioeconomic status (SES) adults with baseline examination between 1987 and 2002 (n = 19,003).
Main Outcome Variables. Weight satisfaction, weight-related health behaviors, chronic health conditions, and clinical health indicators. Statistical Analyses Performed. Chi-square test, t-tests, and linear and multivariate logistic regression. Results. Compared to men, women were more likely to be dieting (32% women; 18% men) and had higher weight dissatisfaction. Men and women with greater weight dissatisfaction reported more dieting, yo-yo dieting, and snacking and consuming fewer meals, being less active, and having to eat either more or less than desired to maintain weight regardless of weight status. Those who were overweight or obese and dissatisfied with their weight had the poorest health. Conclusion. Greater satisfaction with one's weight was associated with positive health behaviors and health outcomes in both men and women and across weight status groups.
To describe longitudinal patterns of objectively measured sedentary behavior from age 12 to 16.
Children participating in the Avon Longitudinal Study of Parents and Children wore accelerometers for one week at age 12, 14 and 16. Participants included boys (n=2591) and girls (n=2845) living in a single geographic location in the U.K. (Bristol). Total minutes per day spent in sedentary behavior, and time spent in blocks of sedentary behavior lasting 10–19 minutes, 20–29 minutes and 30+ minutes are described. Growth curve models were used to determine the rate of change in sedentary behavior from age 12 to 16.
At age 12 the boys and girls, on average, were sedentary for 418.0 (67.7) and 436.6 (64.0) minutes per day respectively, and sedentary behavior increased over time to 468.0 (74.3) and 495.6 (68.9) minutes per day at age 14, and to 510.4 (76.6) and 525.4 (67.4) minutes per day at age 16. Growth curve analyses found that total sedentary behavior increased at a rate of 19.5 (0.7) and 22.8 (0.7) minutes per day per year for the boys and girls respectively. The absolute mean increase in total sedentary behavior (+92.4 min/d and +88.8 min/d for the boys and girls respectively) closely matched the mean decrease in light physical activity (−82.2 min/d and −82.9 min/d for the boys and girls respectively, from age 12 to 16. Time spent in continuous sedentary behavior lasting 30+ minutes increased by 121% from age 12 to 16.
Sedentary behavior increased with age, at the expense of light physical activity. The increase in sedentary behavior lasting 30+ minutes in duration contributed greatly to the increase in total sedentary behavior.
Children; adolescents; longitudinal; patterns; descriptive
Type-2 diabetes is associated with increased risk of cardiovascular disease and elevated C-reactive protein levels (CRP). Aerobic exercise training has been shown to improve CRP, however there are limited data evaluating the effect of other exercise training modalities (aerobic, resistance or combination training) in individuals with type-2 diabetes.
Participants (n=204) were randomized to an aerobic exercise (aerobic), resistance exercise (resistance) or a combination of both (combination) for nine months. CRP was evaluated at baseline and at follow-up.
Baseline CRP was correlated with fat mass, waist circumference, BMI, and VO2 peak (p<0.05). CRP was not reduced following aerobic (0.16 mg·L -1, 95% CI: −1.0, 1.3), resistance (−0.03 mg·L -1, 95% CI: −1.1, 1.0) or combination (−0.49 mg·L -1, 95% CI: −1.5 to 0.6) training compared to control (0.35 mg·L -1, 95% CI: −1.0, 1.7). Change in fasting glucose (r=0.20, p=0.009), glycated hemoglobin (HbA1C) (r=0.21 p=0.005), and fat mass (r=0.19, p=0.016) were associated with reductions in CRP, but not change in fitness or weight (p > 0.05). There were significant trends observed for CRP among tertiles of change in HbA1C (p=0.009) and body fat (p=0.040).
Aerobic, resistance or a combination of both did not reduce CRP levels in individuals with type-2 diabetes. However, exercise related improvements in HbA1C, fasting glucose, and fat mass were associated with reductions in CRP.
Inflammation; Aerobic Training; Resistance Training; Hemoglobin A1C; Adiposity; Fitness
Instrumental activities of daily living (IADLs) are tasks that are necessary for independent community living. These tasks often require intact physical and cognitive function, the impairment of which may adversely affect health in older adults. In the current study, we examined the association between IADL impairment and incident heart failure (HF) in community-dwelling older adults.
Methods and results
Of the 5795 community-dwelling adults, aged ≥65 years, in the Cardiovascular Health Study, 5511 had data on baseline IADL and were free of prevalent HF. Of these, 1333 (24%) had baseline IADL impairment, defined as self-reported difficulty with one or more of the following tasks: using the telephone, preparing food, performing light and heavy housework, managing finances, and shopping. Propensity scores for IADL impairment, estimated for each of the 5511 participants, were used to assemble a cohort of 1038 pairs of participants with and without IADL impairment who were balanced on 42 baseline characteristics. Centrally adjudicated incident HF occurred in 26% and 21% of matched participants with and without IADL impairment, respectively, during >12 years of follow-up [matched hazard ratio (HR) 1.33; 95% confidence interval (CI) 1.11–1.59; P = 0.002]. Unadjusted and multivariable-adjusted HRs for incident HF before matching were 1.77 (95% CI 1.56–2.01; P < 0.001) and 1.33 (95% CI 1.15–1.54; P < 0.001), respectively. IADL impairment was also associated with all-cause mortality (matched HR 1.19; 95% CI 1.06–1.34; P = 0.004).
Among community-dwelling older adults free of baseline HF, IADL impairment is a strong and independent predictor of incident HF and mortality.
Instrumental activities of daily living; Incident heart failure; Propensity score
While combination antiretroviral therapy has extended the life expectancy of those infected with human immunodeficiency virus (HIV), there is a high prevalence of comorbidities that increase the risk of cardiovascular morbidity and mortality among people living with HIV/AIDS (PLWHA). The side effects associated with antiretroviral therapy (ART) lead to multiple metabolic disorders, making the management of these metabolic issues and risk of cardiovascular disease (CVD) in those treated with ART a critical issue. Clinical research trials, primarily clinical exercise, rarely include this population due to unique challenges in research methods with underserved minority populations living with a life threatening illness like HIV/AIDS. This paper describes the rationale and design of a randomized clinical trial evaluating the feasibility of a home-based exercise program designed to increase physical activity (PA) and reduce the risk of CVD in PLWHA.
PLWHA being treated with ART will be randomly assigned to one of two groups: a home-based PA intervention or standard care. All participants will receive an educational weight loss workbook and pedometer for self-monitoring of PA. Only those in the intervention group will receive additional elastic Thera-bands® for strength training and behavioral telephone based coaching.
This study will evaluate the feasibility of a home-based program designed to increase PA among PLWHA. Further, it will evaluate the effectiveness of such a program to decrease modifiable risk factors for CVD as a secondary outcome. This study was funded by the NIH/NINR R21 Grant 1R21NRO11281.
Clinical Trial Identifier NCT01377064
Randomized trial; Cardiovascular disease; HIV; Physical activity; Self care; Study design
To measure the levels and patterns of physical activity, using accelerometers, of 11‐year‐old children participating in the Avon Longitudinal Study of Parents and Children (ALSPAC).
ALSPAC is a birth cohort study located in the former county of Avon, in the southwest of England. This study used data collected when the children were 11 years old.
5595 children (2662 boys, 2933 girls). The children are the offspring of women recruited to a birth cohort study during 1991–2. The median age (95% CI) of the children is now 11.8 (11.6 to 11.9) years.
Physical activity was measured over a maximum of 7 consecutive days using the MTI Actigraph accelerometer.
Main outcome measures
Level and pattern of physical activity.
The median physical activity level was 580 counts/min. Boys were more active than girls (median (IQR) 644 (528–772) counts/min vs 529 (444–638) counts/min, respectively). Only 2.5% (95% CI 2.1% to 2.9%) of children (boys 5.1% (95% CI 4.3% to 6.0%), girls 0.4% (95% CI 0.2% to 0.7%) met current internationally recognised recommendations for physical activity. Children were most active in summer and least active in winter (difference = 108 counts/min). Both the mother and partner's education level were inversely associated with activity level (p for trend <0.001 (both mother and partner)). The association was lost for mother's education (p for trend = 0.07) and attenuated for partner's education (p for trend = 0.02), after adjustment for age, sex, season, maternal age and social class.
A large majority of children are insufficiently active, according to current recommended levels for health.
Abnormally elevated exercise blood pressure is associated with increased risk of cardiovascular disease. Aerobic exercise training has been shown to reduce exercise blood pressure. However, it is unknown if these improvements occur in a dose dependent manner. The purpose of the present study is to determine the effect of different doses of aerobic exercise training on exercise blood pressure in obese postmenopausal women.
Participants (n=404) were randomized to one of 4 groups: 4, 8, or 12 kilocalories per kilogram of energy expenditure per week (kcal/kg/week) or the non-exercise control group for 6 months. Exercise blood pressure was obtained during the 50 watts stage of a cycle ergometer maximal exercise test.
There was a significant reduction in systolic blood pressure at 50 watts in the 4 kcal/kg/week (−10.9 mmHg, p< 0.001), 8 kcal/kg/week (−9.9 mmHg, p= 0.022), and 12 kcal/kg/week (−13.7 mmHg, p<0.001) compared to control (−4.2 mmHg). Only the highest exercise training dose significantly reduced diastolic blood pressure (−4.3 mmHg, p= 0.033) compared to control. Additionally, resting blood pressure was not altered following exercise training (p>0.05) compared to control, and was not associated with changes in exercise systolic (r=0.09, p=0.09) or diastolic (r=0.10, p=0.08) blood pressure.
Aerobic exercise training reduces exercise blood pressure and may be more modifiable than changes in resting blood pressure. A high dose of aerobic exercise is recommended to successfully reduce both exercise systolic and diastolic blood pressure, and therefore may attenuate the CVD risk associated with abnormally elevated exercise blood pressure.
Postmenopausal; Exercise Training; Exercise Blood Pressure; Dose Response; Hypertension
Low serum bilirubin levels have been associated with increased risk for cardiovascular disease, and recent data suggest that lower body fat and reductions in weight are associated with higher bilirubin levels. However, it is unknown if exercise training can increase bilirubin levels and whether a higher dose of exercise will further increase bilirubin levels compared to a lower dose.
The primary aim of our current report is to examine whether exercise dose affects bilirubin levels in obese postmenopausal women from the Dose Response to Exercise in Women (DREW) trial. In addition, we evaluated whether changes in fitness, insulin sensitivity, and waist circumference associated with exercise training were associated with change in bilirubin levels.
Participants (n= 419) were randomized to the control group or 4, 8 and 12 kilocalories per kilogram per week (KKW) of exercise training at an intensity of 50% of aerobic capacity. Total bilirubin levels were evaluated at baseline and at follow-up.
Exercise training significantly increased serum bilirubin levels only in the 12 KKW group (0.044 mg/dL, p=0.026) compared to control (0.004 mg/dL). Subgroup analyses showed that there was a significant increase in bilirubin levels in participants in the 12 KKW group (0.076 mg/dL) who were classified as insulin resistant (HOMA> 2.6), compared to insulin resistant control participants (0.018 mg/dL) (p=0.028).
Our findings suggest that high doses of exercise training are necessary to significantly increase bilirubin levels in previously sedentary postmenopausal women especially in individuals with impaired glucose metabolism.
Antioxidant capacity; physical activity; dose-response; postmenopausal
To analyze the relationship of ideal cardiovascular health to disease-specific death.
Patients and Methods
We used data from the Aerobics Center Longitudinal Study from October 9, 1987, to March 3, 1999, to estimate the prevalence of ideal cardiovascular health in 11,993 individuals (24.3% women) and to examine its relationship with deaths from all causes, cardiovascular disease (CVD), and cancer.
During a mean follow-up of 11.6 years, 305 deaths occurred: 70 (23.0%) from CVD and 127 (41.6%) from cancer. In the entire cohort, only 29 individuals (0.2%) had 7 ideal metrics. After adjusting for age, sex, examination year, alcohol intake, and parental history of CVD, risk of death due to CVD was 55% lower in those participants who met 3 or 4 ideal metrics (hazard ratio, 0.45; 95% confidence interval, 0.27-0.77) and 63% lower in those with 5 to 7 ideal metrics (hazard ratio, 0.37; 95% confidence interval, 0.15-0.95), compared with those who met 0 to 2 ideal metrics. Although not significant, there was also a trend toward lower risk of death due to all causes across incremental numbers of ideal metrics. No association was observed for deaths due to cancer.
The prevalence of ideal cardiovascular health was extremely low in a middle-aged cohort of men and women recruited between 1987 and 1999. The American Heart Association construct reflects well the subsequent risk of CVD, as reflected by graded CVD mortality in relation to the number of ideal metrics.
ACLS, Aerobics Center Longitudinal Study; AHA, American Heart Association; BMI, body mass index; CVD, cardiovascular disease; ICD, International Classification of Diseases; MET, metabolic equivalent; NHANES, National Health and Nutrition Examination Survey
Our group has shown a positive dose-response in maximal cardiorespiratory exercise capacity (VO2max) and heart rate variability (HRV) to 6 months of exercise training but no improvement in VO2max for women ≥60 years. Here, we examine the HRV response to exercise training in postmenopausal women younger and older than 60 years.
We examined 365 sedentary, overweight, hypertensive, postmenopausal women randomly assigned to sedentary control or exercise groups exercising at 50% (4 kcal/kg/week, [KKW]), 100% (8 KKW) and 150% (12 KKW) of the National Institutes of Health (NIH) Consensus Development Panel physical activity guidelines. Primary outcomes included time and frequency domain indices of HRV.
Overall, our analysis demonstrated a significant improvement in parasympathetic tone (rMSSD and high frequency power) for both age strata at 8 KKW and 12 KKW. For rMSSD, the age-stratified responses were: control, <60 years, 0.20 ms, 95% confidence interval (CI)−2.40, 2.81; ≥60 years, 0.07 ms, 95% CI −3.64, 3.79; 4 KKW, <60 years, 3.67 ms, 95% CI 1.55, 5.79; ≥60 years, 1.20 ms, 95% CI −1.82, 4.22; 8-KKW, <60 years, 3.61 ms, 95% CI 0.88, 6.34; ≥60 years, 5.75 ms, 95% CI 1.89, 9.61; and 12-KKW, <60 years, 5.07 ms, 95% CI 2.53, 7.60; ≥60 years, 4.28 ms, 95% CI 0.42, 8.14.
VO2max and HRV are independent risk factors for cardiovascular disease (CVD) mortality. Despite no improvement in VO2max, parasympathetic indices of HRV increased in women ≥60 years. This is clinically important, as HRV has important CVD risk and neurovisceral implications beyond cardiorespiratory function.