Physical activity is important for the prevention of chronic disease morbidity and mortality, and the lack of adequate levels of physical activity represents a growing public health burden around the world. The purpose of this report is to introduce the concept of the “Physical Activity Transition” and to explore the potential effects that declining physical activity levels may play on health and life expectancy as countries undergo economic and demographic changes. Physical activity is related to mortality rates in humans, and the available evidence suggests that the adoption of a lifestyle characterized by lower levels of physical activity will attenuate the expected gains in life expectancy associated with the epidemiological transition. Advances in the measurement of physical activity at work, in the home, for transport, and in leisure time in a wide variety of populations will be integral to advancing the current understanding of how macro-level factors shape physical activity patterns and patterns of morbidity and mortality.
Peter T. Katzmarzyk and Caitlin Mason
Caitlin Mason, Peter T. Katzmarzyk, Cora L. Craig and Lise Gauvin
This study investigates the degree to which the relationship between self-rated health and mortality is consistent across income groups in Canada and whether it can be explained by differentials in physical activity.
A sample of 17,852 adults in the 1981 Canada Fitness Survey was followed for 13 y for mortality.
After adjusting for several confounders, there was a dose-response relationship between self-rated health and all-cause, CVD, and cancer mortality. This relationship persisted across levels of income. Physical activity was inversely related to mortality; however, the risk of mortality associated with low self-rated health did not differ significantly between activity groups.
Physical activity does not appear to be a significant mediating or moderating factor in the relationship between self-rated health and mortality.
Ikuyo Imayama, Catherine M. Alfano, Caitlin E. Mason, Chiachi Wang, Liren Xiao, Catherine Duggan, Kristin L. Campbell, Karen E. Foster-Schubert, Ching-Yun Wang and Anne McTiernan
Regular exercise increases exercise self-efficacy and health-related quality of life (HRQOL); however, the mechanisms are unknown. We examined the associations of exercise adherence and physiological improvements with changes in exercise self-efficacy and HRQOL.
Middle-aged adults (N = 202) were randomized to 12 months aerobic exercise (360 minutes/week) or control. Weight, waist circumference, percent body fat, cardiopulmonary fitness, HRQOL (SF-36), and exercise self-efficacy were assessed at baseline and 12 months. Adherence was measured in minutes/day from activity logs.
Exercise adherence was associated with reduced bodily pain, improved general health and vitality, and reduced role-emotional scores (P trend ≤ 0.05). Increased fitness was associated with improved physical functioning, bodily pain and general health scores (P trend ≤ 0.04). Reduced weight and percent body fat were associated with improved physical functioning, general health, and bodily pain scores (P trend < 0.05). Decreased waist circumference was associated with improved bodily pain and general health but with reduced role-emotional scores (Ptrend ≤ 0.05). High exercise adherence, increased cardiopulmonary fitness and reduced weight, waist circumference and percent body fat were associated with increased exercise self-efficacy (P trend < 0.02).
Monitoring adherence and tailoring exercise programs to induce changes in cardiopulmonary fitness and body composition may lead to greater improvements in HRQOL and self-efficacy that could promote exercise maintenance.