Purpose: Few epidemiological studies have been conducted among middle-aged women on long-term total and specific physical activity (PA) trends. We studied in a cross-sectional setting the relationship of self-reported total daily PA with age and calendar time.
Methods: In a population-based cohort of 38,988 women aged 49-83 yr in central Sweden, information was collected on physical activity, such as work or occupation, household work, walking or bicycling, exercise, watching TV or reading, and other lifestyle factors through a self-administered questionnaire. Total and specific daily PA levels at ages 15, 30, and 50 yr were recalled retrospectively and measured as metabolic equivalents (MET·h·d−1).
Results: Total PA level linearly decreased with calendar time in all three age groups (slope for 5-yr change in calendar time among those 15 yr of age = −0.82; 95% confidence interval (CI), −0.86 to −0.78; among those 30 yr of age=−0.42; 95% CI, −0.45 to −0.38; and among those 50 yr of age = −0.62; 95% CI, −0.66 to −0.58). High-intensity activities such as walking or bicycling decreased by 0.21 MET·h·d−1 (95% CI, −0.22 to −0.20) every 5-calendar-year change among adolescents between the 1930s and 1960s. Total activity level decreased in all age groups by an average of approximately 3MET·h−1·d−1, corresponding to approximately 45 min of brisk walking.
Conclusions: Our results suggest that intervention efforts aimed at engaging in healthful amounts of physical activity are needed throughout the life cycle.
1Division of Nutritional Epidemiology, Institute of Environmental Medicine, Karolinska Institutet, Stockholm, SWEDEN; 2Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, SWEDEN; 3Department of Epidemiology and Biostatistics, Arnold School of Public Health, University of South Carolina, Columbia, SC; and 4Department of Biostatistics, Harvard School of Public Health, Boston, MA
Address for correspondence: Nicola Orsini, Division of Nutritional Epidemiology, Institute of Environmental Medicine, Karolinska Institutet, P.O. Box, SE-171 77, Stockholm, Sweden; E-mail: email@example.com.
Submitted for publication May 2005.
Accepted for publication August 2005.