Physicians may want to advise patients to put down the TV remote and opt for a walk instead, according to a study published in JAMA Network Open.
The cohort study of more than 45,000 female participants 50 or older looked at how replacing television time with more physical activity and sleep—for those sleeping seven hours or less per day—may improve a person’s odds of healthy aging. In the context of this study, healthy aging is defined as survival to 70 years old with no major chronic diseases and no impairment of physical function, memory or mental health.
Generally speaking, just 10% to 35% of older adults ever meet the definition of heathy aging, the study reports. But adding just two hours of light physical activity daily at work boosted the odds of better health by 6%, whereas two additional hours of TV decreased the odds of healthy aging by 12%. The findings from this study point to reassessing daily behavior to improve health, researchers note.
Healthy aging has historically been associated with sleep duration and moderate-to-vigorous physical activity. However, the researchers from the study wanted to explore the association between sedentary behavior, light-intensity physical activity and healthy aging, and what would happen if light and moderate-to-vigorous activity replaced sedentary behavior.
“Identifying modifiable factors for healthy aging can inform interventions to promote this outcome,” write the researchers, who analyzed data from the Nurses’ Health Study on 45,176 women 50 years or older free of major chronic disease in 1992. For 20 years, they prospectively followed these women, conducting a data analysis from January to May 2022.
Assessing behaviors at work, home
Investigators used three measures for sedentary behaviors: hours spent watching television and sitting at work or at home. They also looked at two light-intensity physical activity measures: hours participants stood or walked around at home and at work.
The researchers followed a long list of lifestyle and health variables to assess independent associations of sedentary behavior and light-intensity physical activity with healthy aging. This included factors such as age, education, marital status, annual household income and family history of cancer, myocardial infarction, and diabetes. They also accounted for baseline hypertension and high cholesterol, menopausal status and postmenopausal hormone use, aspirin use, smoking history, alcohol intake, total energy intake, diet quality and sleep duration.
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“Moreover, we calculated the population-attributable risk, an estimate of the percentage of individuals with healthy aging during follow-up that could have been achieved if they engaged in the low-risk category for these behaviors, assuming that the observed associations were causal,” the researchers explain, adding that they “estimated that 61% of usual agers could become healthy agers if they adhere to four lifestyle factors.”
Those factors included less than three hours a day of watching TV, three or more hours per day of light-intensity physical activity at work, 30 minutes or more of standardized moderate-to-vigorous physical activity and not having obesity. Only 11% of participants in this study belonged to the low-risk group, the researchers report.
TV’s health impact
Among the study participants, 8.6% achieved healthy aging.
After adjusting for covariates such as moderate-to-vigorous physical activity, “each increment of two hours per day in sitting watching television was associated with a 12% reduction in the odds of healthy aging,” report the researchers. However, increasing light-intensity physical activity at work by two hours a day increased the odds of healthy aging by 6%.
Replacing one hour of sedentary TV time with light-intensity physical activity at home or work or with moderate-to-vigorous physical activity also increased the odds of healthy aging. The increases were even greater when TV watching was replaced with higher intensities of physical activity, the researchers report.
More sleep was also associated with healthy aging.
“Among participants who slept seven hours per day or less, replacing television time with sleep was also associated with increased odds of healthy aging,” the researchers report.
Overall, TV watching had a greater negative impact on healthy aging than other sedentary behaviors.
“Television watching typically displaces physical activity and thus reduces energy expenditure. Also, studies have reported that individuals who spend more time watching television tend to follow unhealthy eating patterns and increase total energy intake, which have direct associations with disease risk,” says the study.
