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  • Turn It Off: Study Finds TV-Watching Linked to Higher Risk of Later Mobility Disability in Older Adults

    In brief:

    • Study compared survey responses of 134,000 adults, aged 50-71, who were asked about sedentary behavior and physical activity (PA) once in 1995-1996 and again in 2004-2005
    • All participants in the first survey reported no mobility disability; by the 2004-2005 survey, mobility disability was reported at a higher rate among participants with high amounts of sedentary behavior and low amounts of weekly PA(mobility disability status was assigned whenever a respondent reported an inability to walk, or the ability to walk only at an "easy" pace)
    • Strongest association was with time spent watching TV, with mobility disability risk increasing with hours-per-day spent watching TV regardless of reported PA time
    • Respondents who spend more than 5 hours a day watching TV and fewer than 3 hours engaged in PA increased their risk of mobility disability by 65% over referent group

    Older adults who choose to spend most of their time sitting and very little time being physically active risk sacrificing their mobility later on: that's the conclusion of a new study that says adults 50 to 71 who spend more than 5 hours a day watching television and fewer than 3 hours a week being physically active triple their chances of experiencing a mobility disability at some point in the future.

    The study, published in the Journals of Gerontology: Medical Sciences, analyzed data from 134,269 participants in surveys jointly sponsored by the National Institutes of Health (NIH) and the American Association of Retired Persons (AARP) in 1995-1996 and again in 2004-2005. Authors analyzed respondents' self-reported television viewing and other sedentary behaviors and average number of hours per week spent in light- and moderate-intensity physical activity. Next they matched up data sets with respondents' mobility status as reported in the later survey (all respondents used in the study reported no mobility disabilities in the first survey). "Mobility disability" status was assigned whenever a respondent reported an inability to walk, or the ability to walk only at an "easy" pace.

    Researchers were particularly interested in teasing out the impact of television viewing from other sedentary behaviors such as computer time, napping, and sitting without watching TV. On the PA side of the equation, they were interested in finding out to what degree PA offset the debilitating effects of sedentary behavior. Here's what they found:

    • After adjusting for PA, the relationship between total sedentary time to mobility disability was "almost negligible." However, disability increased steadily with increased reported hours of TV time.
    • Compared with the referent group who reported watching no more than 2 hours of TV per day, respondents reporting 3-4 hours per day of TV viewing experienced 25% higher odds of mobility disability. Respondents reporting watching TV for 5 or more hours a day were found to have 65% increased risk of mobility disability.
    • The odds of mobility disability dropped progressively as frequency and intensity of PA increased, although hours spent watching TV consistently pushed odds higher.
    • Respondents who reported 7 or more hours of PA a week and up to 6 hours a day of sitting did not see their risk of mobility disability rise appreciably; however, increased hours of TV time were associated with increased mobility disability risk regardless of the hours spent in PA.

    "Our findings corroborate those of other studies reporting sedentary behavior to be a risk factor for loss of physical function that is distinct from level of moderate-to-vigorous-intensity [PA]," authors write. As for the stronger association between TV time and mobility disability than for the more generic "sitting" time and mobility disability, researchers believe 2 issues could be at play: first, respondents may be reporting TV watching time with greater accuracy; and second, sitting time may be broken up during the day by periods of PA, whereas TV watching tends to take place in long periods of sitting uninterrupted by PA.

    "Sitting and watching TV for long periods, especially in the evening, has got to be one of the most dangerous things that older people can do," lead author Loretta DiPietro, PhD, MPH, told National Public Radio. She speculated that binge-watching made possible by streaming video is likely making the problem worse. "Before binge watching, at least when a show ended you got up and walked around," she told NPR. "It's now possible to watch several hours without moving."

    Authors of the study acknowledge limitations including a sample that was 94% white with a high school education or higher, and no way to know for certain if every respondent was in fact healthy at the time of the first survey. But they believe the data are conclusive despite those weaknesses.

    "Our findings and those of others indicate that reductions in sedentary time, as well as increases in [PA] are necessary in order to maintain health and function in older age—particularly among those who are the least active," authors write. "Current US public health recommendations for [PA] have not addressed sedentary time, but our results suggest doing so may be useful for reducing mobility disability."

    Research-related stories featured in PT in Motion News are intended to highlight a topic of interest only and do not constitute an endorsement by APTA. For synthesized research and evidence-based practice information, visit the association's PTNow website.

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