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Replacing sitting time with 30 minutes of physical activity linked to a longer life

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The study found that the risk drops even when the activity is a low-intensity one, such as light walking.

Swapping as little as half an hour of sitting time each day with physical activity appears to help reduce the risk of early death among middle-aged and older adults, according to a study published online in the American Journal of Epidemiology.

The study also found that the risk drops even when the activity is a low-intensity one, such as light walking.

These findings should be encouraging to sedentary people who find exercise either difficult or distasteful. You don’t need to be a runner to reap the benefits of exercise, this study suggests. Nor do you need to be exercising for huge swaths of time each day.

“If you have a job or lifestyle that involves a lot of sitting, you can lower your risk of early death by moving more often, for as long as you want and as your ability allows — whether that means taking an hourlong high-intensity spin class or choosing lower-intensity activities, like walking,” says Keith Diaz, the study’s lead author and a professor of behavioral medicine at Columbia University, in a released statement.

The important thing is just to get up and move about.

How long and how intense?

According to a recent report by the Centers for Disease Control and Prevention (CDC), one in four adults in the United States spends more than eight hours each day engaged in sedentary behavior — essentially sitting. That prolonged inactivity can have serious health consequences. Previous research has linked long stretches of sitting with an increased risk of high blood pressure, heart disease and early death.

What the research hasn’t been able to pinpoint for us yet, however, is the type of activity — and how much of it — we need to substitute for sedentary behavior in order to lower our odds of disease. The current study tries to answer those questions.

For the study, Diaz and his co-authors analyzed data from 7,999 Americans, aged 45 and older, who had participated in a broader research project examining racial and regional disparities in stroke between 2009 and 2013.

The participants wore an activity monitor for at least four days to measure their physical activity and sedentary behavior. The results provided estimates for how much time they engaged daily in each behavior.

Health records and death certificates showed that 647 of the participants had died by April 1, 2017. The researchers used that data — and the data from the activity monitors — to estimate how the risk of early death would have changed if time spent sitting had been swapped for time being physically active.

Those calculations suggested that swapping 30 minutes of sitting each day with an equal amount of low-intensity physical activity lowered the risk of early death by 17 percent. The risk fell by 35 percent if the activities were moderate- to high-intensity activities ones, such as brisk walking, running or biking.

An important message

The study comes with several caveats. Most notably, the study was observational, so it can’t prove a direct connection between the substitution of activity for sitting and a lower risk of early death.

In addition, the activity monitors were used just once and for only up to seven days. The readings from those monitors may not have accurately represented the true activity (or non-activity) of the participants throughout the years of the study.

Still, the findings are interesting and offer yet another reminder of why it’s a good idea to incorporate movement into our daily lives.

“Our finding that any physical activity provided mortality risk reduction underscores an important public health message that movement in itself (doing ‘something’), irrespective of intensity, is beneficial,” the researchers write. “This might be particularly pertinent for largely sedentary individuals (who comprise much of the US population) and older adults for whom [light-intensity physical activity] might be a more practical and achievable preventive strategy.”

“Nevertheless,” they add, “it should be acknowledge that [moderate-to-vigorous physical activity] provided the most mortality benefit and, thus, should ultimately be the primary target for individuals seeking to mitigate health risk.”

FMI:  You’ll find an abstract of the study on the website for the American Journal of Epidemiology, although the full study is behind a paywall.

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Comments (2)

  1. Submitted by Ray Schoch on 01/15/2019 - 09:39 am.

    This is precisely the sort of report that prompted me to take up “daily walking” 20 years ago, while living in Colorado, and that keeps me doing a “daily constitutional” of a couple miles a day even now, in winter weather that’s generally much less comfortable than in Colorado. I don’t pretend that it’s aerobic, and I finished second-to-last of more than 400 people in a 5K walk at Elm Creek Park back in October, but for me, the more important point was that I finished, and still went on with my other daily activities during the rest of the day. I want to hike in the Colorado mountains in the summer for as long as I can (I’m 74), and the daily constitutional helps me stay in shape to do just that.

  2. Submitted by Solly Johnson on 01/15/2019 - 09:40 pm.

    I’m and old codger (75) and, in addition to walking a few miles several days a week, try to get exercise into daily activities. When the weather permits, I park at the far end of parking lots when shopping, even though my car is an old beater that won’t be harmed by a few more nicks and dents. Generally, I use stairs rather than escalators, stand and wash dishes by hand rather than use a dishwasher, hang clothes on a line rather than the clothes dryer, garden, use a push mower, shovel snow, etc. All of this helps in maintaining fitness, and I don’t even think about the positive benefits as I’m doing them.

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