Global health recommendations are clear: adults aged 18-64 should be doing at least 150 minutes of moderate-intensity physical activity per week, as well as muscle-strengthening activities at least twice a week.
The World Health Organization (WHO) reports that a third of women and a quarter of men worldwide do not devote enough time to this type of activity, which is essential for limiting the effects of sedentary lifestyles. And this is becoming increasingly challenging with the rise in remote working.
Based on the observation that an adult spends an average of nine to 10 hours a day in a seated position, researchers at UiT The Arctic University of Norway set out to determine whether physical activity could reduce the risk of death linked to prolonged sitting.
They sought to establish a minimum duration of physical activity necessary to reverse the trend, by analysing data from 11,989 individuals aged at least 50, equipped with activity sensors, and drawn from four surveys: two carried out in Norway, one in Sweden, and one in the United States, between 2003 and 2019. The data was then linked with death registries.
Published in the British Journal of Sports Medicine, the study estimates that 5,943 participants spent less than 10.5 hours sitting daily, compared with 6,042 who spent more. The research reports that 805 participants died, of whom 357 spent less than 10.5 hours sitting each day, and 448 spent more than 10.5 hours sitting.
This was observed over an average monitoring period of five years.
This data enabled the researchers to conclude that prolonged sitting – that is, for more than 12 hours – is associated with a 38% increased risk of death, compared with a daily sitting time of eight hours. This, however, did not apply to all participants, since moderate-to-vigorous physical activity of at least 22 minutes daily appeared to help reverse this trend.
Around 20 minutes of moderate to vigorous physical activity a day could be enough to counteract the harmful effects of a sedentary lifestyle. This is a minimum amount of time, as the researchers point out that the longer the duration, the lower the risk of death.
“For example, an extra 10 minutes a day was associated with a 15% lower risk of death in those spending fewer than 10.5 sedentary hours, and a 35% lower risk among those spending more than 10.5 sedentary hours, every day,” the study observed.
Note that the duration of physical activity estimated by the Norwegian researchers corresponds with the average duration recommended by the WHO.
Take the stairs or go on foot
This observational study does not establish a direct link between physical activity and a reduced risk of death in sedentary people, especially given that certain factors, such as diet and general health, were not taken into account.
Still, this does not prevent the researchers from concluding that “small amounts of moderate to vigorous physical activity (MVPA) may be an effective strategy to ameliorate the mortality risk from high sedentary time, where accumulating more than 22 minutes of MVPA eliminates the risk of high sedentary time”.
And you don’t have to run a marathon or engage in high-intensity exercise to combat the potential effects of a sedentary lifestyle. According to the WHO, physical activity is defined as “any bodily movement produced by skeletal muscles that requires energy expenditure”.
“Physical activity refers to all movement, including during leisure time, for transport to get to and from places, or as part of a person’s work,” the global health body said. This can involve walking, cycling, sports, active recreation, or play.
Simple actions to adopt on a daily basis include taking the stairs rather than the lift, walking or cycling rather than taking the car for short journeys, or getting off the train or bus one station early to increase your amount of daily physical activity.