Physical activity and heart rate variability in older adults: the Cardiovascular Health Study.

BACKGROUND: Cardiac mortality and electrophysiological dysfunction both increase with age. Heart rate variability (HRV) provides indices of autonomic function and electrophysiology that are associated with cardiac risk. How habitual physical activity among older adults prospectively relates to HRV, including nonlinear indices of erratic sinus patterns, is not established. We hypothesized that increasing the levels of both total leisure-time activity and walking would be prospectively associated with more favorable time-domain, frequency-domain, and nonlinear HRV measures in older adults. METHODS AND RESULTS: We evaluated serial longitudinal measures of both physical activity and 24-hour Holter HRV over 5 years among 985 older US adults in the community-based Cardiovascular Health Study. After multivariable adjustment, greater total leisure-time activity, walking distance, and walking pace were each prospectively associated with specific, more favorable HRV indices, including higher 24-hour standard deviation of all normal-to-normal intervals (Ptrend=0.009, 0.02, 0.06, respectively) and ultralow-frequency power (Ptrend=0.02, 0.008, 0.16, respectively). Greater walking pace was also associated with a higher short-term fractal scaling exponent (Ptrend=0.003) and lower Poincaré ratio (Ptrend=0.02), markers of less erratic sinus patterns. CONCLUSIONS: Greater total leisure-time activity, and walking alone, as well, were prospectively associated with more favorable and specific indices of autonomic function in older adults, including several suggestive of more normal circadian fluctuations and less erratic sinoatrial firing. Our results suggest potential mechanisms that might contribute to lower cardiovascular mortality with habitual physical activity later in life.

Dose response between physical activity and risk of coronary heart disease: a meta-analysis.

BACKGROUND: No reviews have quantified the specific amounts of physical activity required for lower risks of coronary heart disease when assessing the dose-response relation. Instead, previous reviews have used qualitative estimates such as low, moderate, and high physical activity. METHODS AND RESULTS: We performed an aggregate data meta-analysis of epidemiological studies investigating physical activity and primary prevention of CHD. We included prospective cohort studies published in English since 1995. After reviewing 3194 abstracts, we included 33 studies. We used random-effects generalized least squares spline models for trend estimation to derive pooled dose-response estimates. Among the 33 studies, 9 allowed quantitative estimates of leisure-time physical activity. Individuals who engaged in the equivalent of 150 min/wk of moderate-intensity leisure-time physical activity (minimum amount, 2008 U.S. federal guidelines) had a 14% lower coronary heart disease risk (relative risk, 0.86; 95% confidence interval, 0.77 to 0.96) compared with those reporting no leisure-time physical activity. Those engaging in the equivalent of 300 min/wk of moderate-intensity leisure-time physical activity (2008 U.S. federal guidelines for additional benefits) had a 20% (relative risk, 0.80; 95% confidence interval, 0.74 to 0.88) lower risk. At higher levels of physical activity, relative risks were modestly lower. People who were physically active at levels lower than the minimum recommended amount also had significantly lower risk of coronary heart disease. There was a significant interaction by sex (P=0.03); the association was stronger among women than men. CONCLUSIONS: These findings provide quantitative data supporting US physical activity guidelines that stipulate that "some physical activity is better than none" and "additional benefits occur with more physical activity."

Physical activity and risk of stroke in women.

BACKGROUND AND PURPOSE: Physical activity has generally been inversely related to the risk of developing stroke, but details regarding the amount and kinds of activity required are unclear as are associations for specific stroke subtypes. METHODS: Eligible subjects were 39 315 healthy US women, > or =45 years of age, from the Women's Health Study. Women reported physical activity at baseline (1992 to 1995) and at 36, 72, 96, 125, and 149 months' follow-up. During an average follow-up of 11.9 years, 579 women developed incident stroke (473 ischemic, 102 hemorrhagic, and 4 of unknown type). Proportional hazards models related physical activity, updated over time, to the risk of incident stroke. RESULTS: The multivariable relative risks associated with <200, 200 to 599, 600 to 1499, and > or =1500 kcal/week of leisure-time physical activity were 1.00 (referent), 1.11 (95% CI, 0.87 to 1.41), 0.86 (95% CI, 0.67 to 1.10), and 0.83 (95% CI, 0.63 to 1.08), respectively (P trend=0.06). Similar results were observed for ischemic stroke, whereas no associations were observed for hemorrhagic stroke. Vigorous physical activity was not related to stroke risk (P trend=0.50); however, walking time and walking pace were inversely related, either significantly or with borderline significance, to total, ischemic, and hemorrhagic stroke risks (P trend between 0.002 and 0.07). CONCLUSIONS: This study shows a tendency for leisure-time physical activity to be associated with lower stroke risk in women. In particular, walking was generally associated with lower risks of total, ischemic, and hemorrhagic stroke.

Physical activity, adiposity, and risk of endometrial cancer.

OBJECTIVE: We examined the associations of leisure-time physical activity and adiposity with endometrial cancer risk. METHODS: Eligible subjects were 32,642 healthy US women, >or=45 years, from the Women's Health Study. Women reported on questionnaires about their weight, height, and physical activity at baseline (1992-1995) and waist and hip circumference at 72 months. During an average follow-up of 8.8 years, 264 women developed endometrial cancer, confirmed using medical records. RESULTS: The heaviest women (body mass index, BMI >or= 30 kg/m(2)) had more than twice the risk of endometrial cancer as those who were least heavy (BMI < 22.5 kg/m(2)) [multivariable-adjusted relative risk, RR = 2.49 (95% confidence interval (CI) = 1.73, 3.59)]. Neither waist nor waist/hip ratio predicted risk in multivariate analyses. Leisure-time physical activity and walking were also unrelated to risk. Women reporting any vigorous activity had lower risk than those reporting none (multivariable-adjusted RR = 0.74 [0.56, 0.97]) independent of BMI, but there was no trend of declining risk with increasing energy expended in such activities. In examining the joint effects of BMI and physical activity, compared with active (>or=15 MET-h/week), normal weight (BMI < 25) women, those who were both inactive (<15 MET-h/week) and overweight (BMI >or= 25) had higher risk (multivariable-adjusted RR = 1.85 [1.26, 2.72]), as did women who were overweight and active (multivariable-adjusted RR = 1.60 [1.01, 2.54]), whereas normal weight, inactive women (multivariable-adjusted RR = 1.17 [0.77, 1.77]) did not. CONCLUSIONS: This study confirms BMI as a strong predictor of endometrial cancer risk. Central adiposity did not independently predict risk after adjustment for BMI; there also was no clear evidence of an inverse relation with leisure-time physical activity.

Utility and efficacy of a smartphone application to enhance the learning and behavior goals of traditional cardiac rehabilitation: a feasibility study.

PURPOSE: Most eligible patients do not participate in traditional clinic-based cardiac rehabilitation (CR) despite well-established benefits. Novel approaches to overcome logistic obstacles and increase efficiencies of learning, behavior modification, and exercise surveillance may increase CR participation. In an observational study, the feasibility and utility of a mobile smartphone application for CR, Heart Coach (HC), were assessed as part of standard care. Ultimately, innovative CR models incorporating HC may facilitate better CR usage and value. METHODS: Twenty-six patients enrolled in CR installed HC. Over the next 30 days, they were prompted by HC to complete a daily "task list" that included medications, walking, education (text and videos), and surveys. Cardiac rehabilitation providers monitored each patient's progress through a HC-based Web dashboard and also sent them personalized feedback and support. Completion of the tasks and feedback (qualitative and quantitative) from patients and clinicians were tracked. RESULTS: Patients engaged with HC 90% of days during the study period, with uniformly favorable impact on compliance and adherence. Eighty-three percent of patients reported a positive/very positive HC experience. Providers reported that HC enhanced their provision of therapy by improving communication, clinical insight, patient participation, and program efficiency. CONCLUSIONS: Integrating a mobile care delivery platform into CR was feasible, safe, and agreeable to patients and clinicians. It enhanced patient perceptions of CR care and physician perceptions of the CR caregiving process. Mobile-enabled technologies hold promise to extend the quality and reach of CR, and to better achieve contemporary accountable care goals.

Trans-fatty acid consumption and heart rate variability in 2 separate cohorts of older and younger adults.

BACKGROUND: Trans-fatty acid (TFA) consumption is associated with risk of coronary heart disease, and trans-18:2, but not trans-18:1, in red blood cell membranes has been associated with sudden cardiac arrest. Abnormal heart rate variability (HRV) reflects autonomic dysfunction and predicts cardiac death. Relationships between TFA consumption and HRV remain understudied. We determined whether total TFA consumption, as well as trans-18:1 and trans-18:2 TFA consumption, was independently associated with HRV in 2 independent cohorts in the United States and Portugal. METHODS AND RESULTS: In 2 independent cohorts of older US adults (Cardiovascular Health Study [CHS], age 72±5 years, 1989/1995) and young Portuguese adults (Porto, age 19±2 years, 2008/2010), we assessed habitual TFA intake by food frequency questionnaires in CHS (separately estimating trans-18:1 and trans-18:2) and multiple 24-hour recalls in Porto (estimating total TFA only, which in a subset correlated with circulating trans-18:2 but not trans-18:1, suggesting that we captured the former). HRV was assessed using 24-hour Holters in CHS (n=1076) and repeated short-term (5-minute) ECGs in Porto (n=160). We used multivariate-adjusted linear regression to relate TFA consumption to HRV cross-sectionally (CHS, Porto) and longitudinally (CHS). In CHS, higher trans-18:2 consumption was associated with lower 24-hour SD of all normal-to-normal intervals both cross-sectionally (-12%; 95% CI, -19% to -6%; P=0.001) and longitudinally (-15%; 95% CI, -25% to -4%; P= 0.009) and lower 24-hour SD of 5-minute average N-N intervals and mean of the 5-minute SD of N-N intervals calculated over 24 hours (P<0.05 each). Higher trans-18:1 consumption in CHS was associated with more favorable 24-hour HRV in particular time-domain indices (24-hour SD of all normal-to-normal intervals, SD of 5-minute average N-N intervals, mean of the 5-minute SD of N-N intervals calculated over 24 hours; P<0.05 each). In Porto, each higher SD TFA consumption was associated with 4% lower 5-minute 24-hour SD of all normal-to-normal intervals (95% CI, -8% to -1%; P=0.04) and 7% lower 5-minute square root of the mean of the squares of successive N-N differences (95% CI, -13% to -1%; P=0.04). CONCLUSIONS: Trans-18:2 consumption is associated with specific, less favorable indices of HRV in both older and young adults. Trans-18:1 consumption is associated with more favorable HRV indices in older adults. Our results support the need to investigate potential HRV-related mechanisms, whereby trans-18:2 may increase arrhythmic risk.

Effects of physical activity on cardiovascular and noncardiovascular outcomes in older adults.

Aging is associated with a cascade of morphologic and physiologic changes that naturally predispose older adults to progressive weakening, functional decline, morbidity, disability, poor quality of life, and increased mortality. Physical activity moderates such insidious aging patterns and is a vital preventive and therapeutic strategy to optimize health throughout the aging process. Regular exercise provides many physiologic benefits, reduces risk of disease outcomes, and triggers important psychological gains. Advanced age presents distinctive obstacles to maintaining a physically active lifestyle. Individualized exercise strategies and regimens make it possible, however, for every elderly adult to benefit from physical activity.