Just 25 mins of exercise enough to cut death risk from sitting long

A highly sedentary lifestyle is associated with a heightened risk of death, said the researchers from the University of Tromso in Norway. 

The study of about 12,000 people aged at least 50 showed that being sedentary for more than 12 hours a day was associated with a 38 per cent heightened risk of death compared with a daily tally of eight hours -- but only among those totaling up fewer than 22 daily minutes of moderate to vigorous physical activity.

More than 22 daily minutes of moderate to vigorous physical activity was associated with a lower risk of death.

While a higher amount of moderate to vigorous physical activity was associated with a lower risk of death, irrespective of the amount of sedentary time, the association between sedentary time and death was largely influenced by the amount of moderate to vigorous physical activity. 

For example, an extra 10 minutes a day was associated with a 15 per cent lower risk of death in those spending fewer than 10.5 sedentary hours, and a 35 per cent lower risk among those spending more than 10.5 sedentary hours, every day.

Light-intensity physical activity was only associated with a lower risk of death among highly sedentary people (12+ daily hours).

This is an observational study, and as such, can't establish cause and effect, said the researchers.

Nevertheless, the researchers noted, "Small amounts of MVPA [moderate to vigorous physical activity] 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.” 

“Efforts to promote physical activity may have substantial health benefits for individuals," they said.