Sedentary Behaviors, Light-Intensity Physical Activity, and Healthy Aging

Area of Science:

• Gerontology
• Public Health
• Epidemiology

Background:

• Sleep duration and moderate-to-vigorous physical activity (MVPA) are linked to healthy aging.
• Associations between sedentary behaviors, light-intensity physical activity (LPA), and healthy aging remain unclear.

Purpose of the Study:

• To investigate the independent associations of sedentary behaviors and LPA with healthy aging.
• To assess the impact of substituting sedentary behavior with LPA, MVPA, or sleep on healthy aging.

Main Methods:

• A prospective cohort study of over 45,000 women from the Nurses' Health Study, aged 50+ and free of chronic diseases in 1992, followed for 20 years.
• Sedentary behaviors (TV watching, work sitting, home sitting) and LPA (at home, at work) were assessed.
• Healthy aging defined as survival to 70+ with no major chronic diseases or impairments in memory, physical, or mental health; isotemporal substitution models used.

Main Results:

• Increased TV watching was associated with a 12% reduction in odds of healthy aging.
• Increased work-based LPA was associated with a 6% increase in odds of healthy aging.
• Replacing TV time with LPA (at home or work) or MVPA increased odds of healthy aging; replacing TV time with sleep also benefited those sleeping <=7 hours.

Conclusions:

• Longer TV watching time is detrimental to healthy aging, while LPA and MVPA are beneficial.
• Rearranging 24-hour behavior, specifically reducing sedentary time and increasing physical activity or sleep, can promote healthy aging.