It may seem the opposite of dangerous, but sitting all day can kill you. Past studies have shown that sedentary behaviour is linked to poor health outcomes, including heart disease, Type 2 diabetes, cancer, and early death.

New research just published however, has found that even short periods of exercise – 20 to 25 minutes per day – can make a major dent in the risk of death for those who sit for long stretches.

“The effect of doing physical activity on a regular basis is astonishing – you could say exercise is both prevention and medicine, like brushing your teeth for avoiding cavities,” says Edvard Sagelv, PhD, an author of the study and a researcher in the school of sport sciences at the UiT the Arctic University of Norway, in Tromsø.

A Little Exercise Goes a Long Way

The analysis, presented in the British Journal of Sports Medicine, drew on four major datasets from Norway, Sweden, and the United States that recorded health information on nearly 12,000 adults ages 50 and up between 2003 and 2019.

Participants wore a physical activity tracking device for a minimum of four days, at least 10 hours per day, and were monitored for at least two years.

About half of the study subjects spent fewer than 10.5 hours sitting down every day, while the rest clocked 10.5 or more sedentary hours. (Based on previous research, Dr. Sagelv and his colleagues estimated that adults in Western countries spend an average of 9 to 10 hours a day being sedentary, mostly during working hours.)

Linking health data with death registries, scientists found that about 7 percent of participants died during an average five-year follow-up period. Among that group, the authors found that participants who sat for more than 12 hours a day had a 38 percent higher likelihood of death than those who were sedentary an average of eight hours a day – but only those who sat 12 hours and also logged less than 22 daily minutes of moderate to vigorous physical activity were at greater risk.

In other words, more moderate to vigorous physical activity was associated with a lower risk of death regardless of the amount of sedentary time.

The More Activity, the Lower the Risk

An extra 10 minutes a day of exercise for example, was linked with a 15 percent lower risk of death in those who spent fewer than 10.5 hours sitting.

For those who sat more than 10.5 hours per day, that additional 10 minutes of activity had an even greater impact – the extra exercise was associated with a 35 percent lower likelihood of premature death.

Sagelv noted that death risk generally levelled off at about 40 minutes of exercise per day for those with high sedentary time. He added that no amount of exercise was harmful and overall, the higher the level, the lower the risk.

Light-intensity physical activity was associated with a lower risk of death only among highly sedentary people -those who sat 12 or more hours daily.

How to Get at Least the Minimum Physical Activity

While the findings encourage at least 20 to 25 minutes of exercise a day, this is an average. Sagelv suggests that people may expect to see similar benefits doing 150 minutes per week divided into different activity periods, such as 50 minutes three days a week, as long as it averages 20 to 25 minutes daily.

“The key is continuous engagement,” says Sagelv. “The challenge is to find the time and make an effort to move, which people may not like. It is more comfortable to lie on the couch.”

For Jay Dawes, PhD, an associate professor of applied exercise science at Oklahoma State University in Stillwater, the study results themselves may be a good motivator.

“It’s a shockingly small amount of time exercising that can have a pretty significant impact in reducing your risk of dying,” he says.

Dr. Dawes, who was not involved in the study, adds that an activity-tracking device, like that worn by the people in this study, can also provide inspiration to stick with an exercise program.

“If you have a device that easily measures progress and tracks your results over time, it can be incredibly motivating,” he says.

He further advises blocking out time on the calendar to exercise, and making that activity a priority. For some, morning workouts can be best because they rev up the metabolism and can boost productivity and alertness throughout the day, according to Dawes. Plus, some research indicates that morning exercise may produce better results when it comes to weight loss.

“Still, some people aren’t morning people,” he says.

“You need to find a time and activity that works best for you.”

There are many ways to get moderate to vigorous exercise, including brisk walking, walking at a normal pace up a hill, cycling at normal pace, gardening, or even playing with kids, suggests Sagelv.

“If super busy, always take the stairs or jump off your bus one stop before your destination and walk the final mile,” he says.