Objectives The aim was to examine the independent and joint associations of sitting time and physical activity with risk of incident cardiovascular disease (CVD). Background Sedentary behavior is recognized as a distinct construct beyond lack of leisure-time physical activity, but limited data exists on the interrelationship between these two components of energy balance. Methods Participants in the prospective Women’s Health Initiative Observational Study (N = 71,018), aged 50–79 and free of CVD at baseline (1993–1998), provided information on sedentary behavior, defined as hours of sitting per day, and usual physical activity at baseline and during follow-up through September 2010. First CVD (coronary heart disease or stroke) events were centrally adjudicated. Results Sitting ≥ 10 hours/day compared to ≤ 5 hours/day was associated with increased CVD risk (HR=1.18, 95% CI 1.09, 1.29) in multivariable models including physical activity. Low physical activity was also associated with higher CVD risk (P, trend <0.001). When women were cross-classified by sitting time and physical activity (P, interaction = 0.94), CVD risk was highest in inactive women (≤1.7 MET-hrs/week) who also reported ≥10 hrs/day of sitting. Results were similar for CHD and stroke when examined separately. Associations between prolonged sitting and risk of CVD were stronger in overweight versus normal weight women and women aged 70 years and older compared to younger women. Conclusions Prolonged sitting time was associated with increased CVD risk, independent of leisure-time physical activity, in postmenopausal women without a history of CVD. A combination of low physical activity and prolonged sitting augments CVD risk.

Background Previous studies on gene-lifestyle interaction and obesity have mostly focused on the FTO gene and physical activity, while little attention has been paid to sedentary behavior as indicated by television (TV) watching. Methods and Results We analyzed interactions between TV watching, leisure-time physical activity and genetic predisposition in relation to body mass index (BMI) in 7740 women and 4564 men from 2 prospective cohorts: the Nurses’ Health Study and Health Professionals Follow-up Study. Data on physical activity and TV watching were collected 2 years prior to assessment of BMI. A weighted genetic risk score (GRS) was calculated on the basis of 32 established BMI-associated variants. In both women and men, the genetic associations with BMI strengthened with increased hours of TV watching. An increment of 10 points in the weighted GRS was associated with 0.8 [SE 0.4], 0.8 [0.2], 1.4 [0.2], 1.5 [0.2] and 3.4 [1.0] kg/m2 higher BMI across the 5 categories of TV watching (0-1, 2-5, 6-20, 21-40, and >40h/wk) (P for interaction=0.001). In contrast, the genetic association with BMI weakened with increased levels of physical activity. An increment of 10 points in the weighted GRS was associated with 1.5 [0.2], 1.3 [0.2], 1.2 [0.2], 1.2 [0.2] and 0.8 [0.2] kg/m2 higher BMI across the quintiles of physical activity. The interactions of TV watching and physical activity with genetic predisposition in relation to BMI were independent of each other. Conclusions Sedentary lifestyle indicated by prolonged TV watching may accentuate predisposition to elevated adiposity, whereas greater leisure-time physical activity may attenuate the genetic association.

Background Overall mortality rates from coronary heart disease (CHD) in the U.S. have declined in recent decades, yet the rate has plateaued among younger women. The potential for further improvement in mortality rates among young women through changes in lifestyle is unknown. Objectives To estimate the proportion of CHD cases and clinical cardiovascular disease (CVD) risk factors among young women that might be attributable to poor adherence to a healthy lifestyle. Methods We conducted a prospective analysis among 88,940 women, aged 27–44 years at baseline, in the Nurses’ Health Study II and followed from 1991 – 2011. Lifestyle factors were updated repeatedly by questionnaire. A healthy lifestyle was defined as not smoking, normal body mass index (BMI), physical activity ≥ 2.5 hours/week, television ≤ 7 hours/week, diet in top 40% of the Alternative Healthy Eating Index-2010, and 0.1 – 14.9 g/day of alcohol. To estimate the proportion of CHD and clinical CVD risk factors (diabetes, hypertension, hypercholesterolemia) that could be attributed to poor adherence to a healthy lifestyle, we calculated the population attributable risk percent. Results During 20 years of follow-up, we documented 456 incident CHD cases. In multivariable-adjusted models, non-smoking, healthy BMI, exercise, and healthy diet were independently and significantly associated with lower CHD risk. Compared to women with no healthy lifestyle factors, the hazard ratio (HR) for CHD for women with 6 lifestyle factors was 0.08 (95% CI: 0.03 to 0.22). Approximately 73% (95% CI: 39%to 89%) of CHD cases were attributable to poor adherence to a healthy lifestyle. Similarly, 46% (95% CI: 43%to 49%) of clinical CVD risk factor cases were attributable to poor lifestyle. Conclusions Primordial prevention through maintenance of a healthy lifestyle among young women may substantially lower the burden of CVD.

Purpose To compare the degree to which four accelerometer metrics—total activity counts per day (TAC/d), steps per day (steps/d), physical activity energy expenditure (PAEE, kcal/kg/day), and moderate- to vigorous-intensity physical activity (MVPA, min/d)— were correlated with PAEE measured by doubly-labeled water (DLW). Additionally, accelerometer metrics based on vertical axis counts and triaxial counts were compared. Methods This analysis included 684 women and 611 men aged 43 – 83 years. Participants wore the Actigraph GT3X on the hip for seven days twice during the study and the average of the two measurements was used. Each participant also completed one DLW measurement, with a subset having a repeat. PAEE was estimated by subtracting resting metabolic rate and the thermic effect of food from total daily energy expenditure estimated by DLW. Partial Spearman correlations were used to estimate associations between PAEE and each accelerometer metric. Results Correlations between the accelerometer metrics and DLW-determined PAEE were higher for triaxial counts than vertical axis counts. After adjusting for weight, age, accelerometer wear time, and fat free mass, the correlation between TAC/d based on triaxial counts and DLW-determined PAEE was 0.44 in women and 0.41 in men. Correlations for steps/d and accelerometer-estimated PAEE with DLW-determined PAEE were similar. After adjustment for within-person variation in DLW-determined PAEE, the correlations for TAC/d increased to 0.61 and 0.49, respectively. Correlations between MVPA and DLW-determined PAEE were lower, particularly for modified bouts of ≥10 minutes. Conclusion Accelerometer measures that represent total activity volume, including TAC/d, steps/d, and PAEE, were more highly correlated with DLW-determined PAEE than MVPA using traditional thresholds and should be considered by researchers seeking to reduce accelerometer data to a single metric.

Purpose Although studies have shown health benefits for moderate-intensity physical activity, there is limited evidence to support beneficial effects for high amounts of vigorous activity among middle-aged and older men. The objective of this study was to examine the relationship between vigorous-intensity physical activity, compared to moderate-intensity activity, and risk of major chronic disease in men. Methods We prospectively examined the associations between vigorous- and moderate-intensity physical activity and risk of major chronic disease among 44,551 men aged 40–75 years in 1986. Leisure-time physical activity was assessed biennially by questionnaire. During 22 years of follow-up, we documented 14,162 incident cases of major chronic disease, including 4769 cardiovascular events, 6449 cancer events, and 2944 deaths from other causes. Results The hazard ratio (HR) of major chronic disease comparing ≥ 21 to 0 MET-hours/week of exercise was 0.86 (95% CI: 0.81, 0.91) for vigorous-intensity activity and 0.85 (95% CI: 0.80, 0.90) for moderate activity. For CVD, the corresponding HR were 0.78 (95% CI: 0.70, 0.86) and 0.80 (95% CI: 0.72, 0.88), respectively. When examined separately, running, tennis, and brisk walking were inversely associated with CVD risk. Furthermore, more vigorous activity was associated with lower disease risk; the HR comparing >70 to 0 MET-hours/week of vigorous-intensity exercise was 0.79 (95% CI: 0.68, 0.92; P <0.0001 for trend) for major chronic disease and 0.73 (95% CI: 0.56, 0.96; P <0.0001 for trend) for CVD. Conclusions Vigorous- and moderate-intensity physical activity were associated with lower risk of major chronic disease and cardiovascular disease. Increasing amounts of vigorous activity remained inversely associated with disease risk, even among men in the highest categories of exercise.

Both training protocols improved strength, balance, and functional performance. More clinicians should incorporate hop-to-stabilization exercises into their rehabilitation protocols to improve the deficits associated with CAI.

Statistically, after the 6-week intervention, all groups improved in global and regional health-related quality of life. Clinicians should compare patient-reported outcomes with clinical measures to have a better understanding of progression during rehabilitation.

Background Physical activity is important for maintaining healthy weight. The time of day when exercise is performed—a highly discretionary aspect of behavior— may impact weight control, but evidence is limited. Thus, we examined the association between the timing of physical activity and obesity risk in women. Methods A cross-sectional analysis was conducted among 7157 Women’s Health Study participants who participated in an ancillary study begun in 2011 that is measuring physical activity using accelerometers. The exposure was percentage of total accelerometer counts accumulated before 12:00 noon and the outcome was obesity. Results Mean (±SD) BMI among participants was 26.1 (±4.9) kg/m2 and 1322 women were obese. The mean activity counts per day was 203,870 (±95,811) of which a mean 47.1% (±11.5%) were recorded in the morning. In multivariable-adjusted models, women who recorded <39% (lowest quartile) of accelerometer counts before 12:00 noon had a 26% higher odds of being obese, compared to those recording ≥54% (highest quartile) of counts before noon (Ptrend = 0.02). Conclusions These study findings—that women who are less active during morning hours may be at higher risk of obesity—if confirmed can provide a novel strategy to help combat the important health problem of obesity.