Thirty minutes of exercise a day is enough to stay healthy.

For anyone interested in the relationship between exercise and longevity, one of the most prevalent questions is how much exercise do we need to do to stay healthy. Is thirty minutes a day enough? Can we get along with less? Do we need to do the whole exercise in one session or can we spread it out throughout the day? And when we talk about exercise, does it have to be hard to work?

Scientists have spent years trying to quantify the ideal exercise dose for most people. They finally reached broad consensus in 2008 on the Physical Activity Guidelines for Americans, which were updated in 2018 after an extensive review of available scientific information on movement and health. Both versions of the guidelines recommended that everyone who is physically fit to do so accumulate 150 minutes of moderate exercise a week, or half that if the exercise is intense.

But what is the best way to distribute these weekly minutes? And what does “moderate” mean? Here’s what some of exercise science’s top researchers say about step counting, going up and down stairs, the “weekend warriors,” greater longevity, and why the healthiest step we can take is the one that pushes us away from the couch.

Look for the ideal time of 150 minutes per week

“One hundred and fifty minutes a week of moderate-to-vigorous physical activity is clearly enough to promote longevity,” said Dr. I-Min Lee, professor of epidemiology at Harvard’s TH Chan School of Public Health. She has studied movement and health extensively and helped write current US guidelines on physical activity.

For practical purposes, exercise physiologists often recommend splitting the 150-minute weekly sessions into 30-minute brisk walking sessions or a similar activity.

“It is clear from numerous well-conducted epidemiological studies that 30 minutes of moderate-intensity activity most days of the week reduces the risk of premature death and many diseases such as stroke, heart attack, type 2 diabetes, and many types of diabetes. of cancer,” said Ulf Ekelund, a professor specializing in the epidemiology of physical activity at the Norwegian School of Sport Science in Oslo, who has led many of these studies.

According to him, moderate exercise means “activities that speed up your breathing and heart rate so that exertion feels like it’s a five or six on a scale of one to ten.” In other words, if you tend to walk slowly, pick up your pace a little, but don’t feel obligated to run.

Chopped exercise throughout the day

You can also break your workout into even smaller segments. “It doesn’t matter if the exercise is done in one long continuous 30-minute session or if it’s spread out into shorter sessions throughout the day,” said Emmanuel Stamatakis, an exercise physiologist at the University of Sydney in Australia who studies physical activity and health. .

According to him, numerous recent studies show that we can accumulate our 150 minutes a week of moderate exercise in whatever way suits us best. “Many people find it easier to include a few dozen one- or two-minute walks between work tasks” or other commitments. “A continuous 30-minute session of exercise doesn’t have some special magic” that confers the greatest health benefits.

Stamatakis said you can think of these tiny sessions as exercise “snacks.” “Activities like walking very briskly for a while, climbing stairs and carrying bags full of groceries provide great opportunities for snacking on the go,” he said. To focus the benefits of these workout nuggets, he added, keep the intensity relatively high so that you feel a little out of breath.

It is also conceivable to do all of your exercise for the week in long sessions on Saturdays and Sundays. In a 2017 study conducted by Stamatakis and colleagues, people who reported exercising almost exclusively on weekends were less likely to die early than people who said they almost never exercised. But being a “weekend warrior” has its downsides.

“It’s by no means ideal to be totally sedentary from Monday to Friday and try to make up for it over the weekend,” Stamatakis said. On days when you don’t exercise, you may miss out on many of the benefits of regular exercise, such as glycemic control and improved mood, he said. And that increases the risk of suffering exercise-related injuries.

count your steps

The recommendations remain the same if you measure your exercise in steps rather than minutes. For most people, I-Min Lee said, “150 minutes a week of exercise would translate to 7 steps a day.” A large-scale study by Lee and Ekelund on the relationship between steps and longevity, published in March in The Lancet, concluded that the optimal number of steps per day for people up to 60 was between 8,000 and 10,000, and for aged 60 and over, between 6 and 8 thousand steps per day.

think about doing more

Of course, these recommendations on steps and minutes are about health and longevity, not physical performance. “If you want to run a marathon or a ten-kilometer run as soon as possible, you need to exercise a lot more,” Ekelund said.

The recommended 150 minutes a week may also not be enough to prevent weight gain as you age. In a 2010 study of nearly 35,000 women led by Lee, participants who walked or did other moderate exercise for about an hour a day in middle age maintained their weight as they aged.

So if you have the time and energy, move for more than 30 minutes a day, recommend Lee and the other scientists. In general, according to Lee’s research and other studies, the more active we are, spending a lot of 30 minutes a day, the lower our risk of suffering from chronic diseases and the longer we can live.

But any activity is better than nothing. “Every minute counts,” said Ekelund. “Climbing the stairs has health benefits, even if it only lasts a minute or two if you do it regularly.”

Translation by Clara Allain