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TOPLINE:
Sedentary behavior, particularly sitting and watching television, is linked to lower odds of healthy aging. However, substituting TV time with any physical activity—or even sleep for women with inadequate sleep—may lead to better overall health.
METHODOLOGY:
While previous studies have shown that replacing sedentary behavior with physical activity can improve mortality outcomes, the impact on overall health has remained unclear. To address this, researchers analyzed data from the Nurses’ Health Study, a prospective cohort study. They included 45,176 women aged over 50 years in 1992 (mean age 59.2 years) who were free of major chronic diseases and followed them for 20 years.
In 1992, validated questionnaires recorded participants’ sedentary behavior, levels of physical activity, and sleep patterns. The primary measure of sedentary behavior was time spent watching television. Healthy aging was defined as survival to at least 70 years old with maintenance of four health domains: being free of 11 major chronic diseases, and having no impairment in subjective memory, physical function, or mental health.
TAKEAWAY:
After 20 years of follow-up, 8.6% of the women achieved healthy aging. Additionally, 41.4% were free of the 11 chronic diseases, 16.1% had no physical function impairment, 44.1% had no mental health limitations, and 51.9% reported no memory impairment.
For each additional two hours per day spent sitting and watching television, the odds of healthy aging dropped by 12% (95% CI, 7%-17%). In contrast, an extra two hours per day of low-level physical activity at work increased the odds of healthy aging by 6% (95% CI, 3%-9%). Furthermore, each additional hour per day of moderate to vigorous physical activity (such as normal-paced walking) was associated with a 14% higher chance (95% CI, 11%-16%) of healthy aging.
Theoretical modeling suggested that individuals could improve their odds of healthy aging by replacing one hour of television time per day with low levels of physical activity at home or work, moderate to vigorous physical activity, or even sleep for those sleeping less than seven hours.
IN PRACTICE:
“These findings expand on the literature reporting that replacing sedentary behavior with light or moderate to vigorous physical activity is associated with decreased mortality by suggesting that this increased lifespan might be accompanied by better overall health,” the authors wrote.
SOURCE:
Hongying Shi, PhD, from the Department of Epidemiology and Health Statistics at Wenzhou Medical University, China, led the study, which was published online in JAMA Network Open.
LIMITATIONS:
The study’s measures of behavior were self-reported, which may be less accurate than objective methods. This potential measurement error could have reduced the observed effects of low levels of physical activity. Additionally, the single assessment at baseline may not reflect long-term activity patterns.
DISCLOSURES:
The lead author was supported by the National Social Science Foundation Project of China and the Zhejiang Provincial Philosophy and Social Sciences Planning Project. A coauthor and the Nurses’ Health Study received support from the US National Institutes of Health. The authors declared no conflicts of interest.
