People who sit for a very long time every day run the risk of dying earlier. Physical activity is recommended as compensation. It was unclear how much sport is needed to pay off the "sitting debt" but a new study now provides more certainty.
"Sitting is the new smoking": This statement has become very catchy in the media. In fact, many scientists agree that sitting for extensive periods of time can harm the body. As compensation, sports activity is recommended. The guidelines from the World Health Organization recommend at least 150 minutes of moderate or 75 minutes of intensive endurance sports per week. It is unclear whether this is really sufficient to compensate for the negative effects of sitting for too long. A new study recently published in the Journal of the American College of Cardiology may have an answer to this question.
The study is based on data from around 150,000 women and men interviewed in New South Wales, Australia, from 2006 to 2009 about their sitting and movement habits. Subsequently, patients were monitored for between 7 to 9 years, and all-cause mortality and mortality from cardiovascular events were measured. The researchers then established a relationship between mortality and sitting time or activity. To exclude potential confounder factors, the results were monitored for age, gender, educational level, social relationships, self-assessed health, body mass index, nicotine abuse, psychological stress, healthy diet, and diabetes. The researchers classified the subjects according to their sitting habits into "less seated" (< 4 or 4-6 hours a day) or "more seated" (6-8 or > 8 hours a day). Subjects who sat for more than 8 hours a day were also considered "extreme seated persons".
The study results show that frequent seaters increased their risk of death with every additional sitting hour. This ended to the extent that extreme-seaters who sat for more than 8 hours a day and did no sports as compensation showed an increased mortality risk of around 80%. Their risk of dying from cardiovascular disease was even about twice as high. Only extreme-seaters who had exercised for about 5 to 7 hours a week as compensation had a normal risk profile.
The study also provides information on people who sit for more than 6 hours a day: people could have reduced their mortality risk by around 22% if they had walked for one hour a day instead of sitting for one hour. If the frequently seating people had been exercising intensively for one hour, their mortality risk would have been reduced by as much as 31%. The effects on cardiovascular risk were even more pronounced. Frequent-seaters could have reduced it by around 64% if they had spent an hour a day doing intensive sports instead of sitting. It is interesting to note that frequent seaters could not reduce their mortality by standing more.
Also, the less-frequent seaters were examined in the study. Those who did not participate in sports had a 30% increased risk of death and a 60% increased risk of cardiovascular death. Less frequently seating patients, who were physically active for about 2.5 hours per week, had a normal risk. In concrete terms, this means that if the "lazy" (i.e. non-active) less-frequent seaters, for example, had been intensively exercising for an hour instead of sitting for an hour, their risk of death would have been reduced by around 8% and their risk of cardiovascular death by around 28%. Even more, "standing" would have slightly helped the less fortunate (in contrast to the more fortunate).
The study proves that prolonged sitting is a cardiovascular risk factor that should not be underestimated and increases the probability of premature death. The collection of a "sitting anamnesis" would, therefore, make sense in everyday medical practice. Furthermore, the study shows how much exercise is necessary to compensate for "sitting debt". Those with less or long seating frequencies should follow the recommendations of the World Health Organization and exercise for at least 150 minutes a week. In contrast, extreme-seaters (> 8 hours a day) should exercise significantly more. The study disappoints those who want to compensate too long sitting by standing more. No notable effect could be proven here. A certain amount of exercise always seems to be necessary.
Source:
Stamatakis E et al. Sitting Time, Physical Activity, and Risk of Mortality in Adults. JACC Vol. 73, April 30, 2019:2062-72. https://doi.org/10.1016/j.jacc