Study sheds light on creeping inactivity in midlife

by Leo Almazora27 Aug 2018

Adults in midlife are putting their health at risk by becoming increasingly sedentary, suggests a new paper in the American Journal of Epidemiology.

The paper, titled Ten-Year Changes in Accelerometer-Based Physical Activity and Sedentary Time During Midlife: The CARDIA Study, tracked the changes in activity of almost 1,000 adult subjects in the US who were between 38 and 50 years old at the start of the study.

In the first year of the study (2005-2006), researchers from the University of Texas Health Science Center asked participants to wear an accelerometer on their hip for seven consecutive days during all waking hours, except during water-based activities.  Follow-up measurements were made a decade later using identical protocols.

The study found that participants decreased light physical activity, such as walking, by an average of 30 minutes per day. Meanwhile, their sedentary time had increased by roughly 40 minutes per day. The changes in activity levels during midlife were observed equally among men and women.

“We know higher intensity physical activity tends to decline with age,” said lead author Kelley Pettee Gabriel in a statement. “But these findings show just how much even gentle forms of activity that are part of daily routines, like casual walking, slip in midlife, which doesn't bode at all well for future health and should serve as a wake-up call to us all.”

The study results run parallel to a recent survey of 2,964 Canadians conducted by Desjardins, which found that nearly 30% of respondents do not engage in any form of physical activity. The government of Canada recommends a minimum of 150 minutes a week of exercise for adults; the World Health Organization (WHO) suggests at least 150 minutes of moderate physical exercise or 75 minutes of vigorous aerobic exercise weekly.

“Making relatively small lifestyle changes and taking advantage of missed opportunities to be physically active could have a crucial bearing on how people are setting themselves up for being more resilient during older adulthood," Gabriel said.


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