In recent years a number of research groups have identified statistical relationships between time spent sitting and mortality rate. Some have claimed that longer sitting time correlates with raised mortality rates even for individuals who exercise regularly. Given the large studies showing that even modest levels of activity, such as walking or cleaning the house, associate with better health and lower mortality rates, when taken together this suggests that the problem with sitting is that the sitter is inactive. Here is the latest in the line of studies associating sitting and mortality:
In order to properly assess the damaging effects of sitting, the study analyzed behavioral surveys from 54 countries around the world and matched them with statistics on population size, actuarial table, and overall deaths. Researchers found that sitting time significantly impacted all-cause mortality, accounting for approximately 433,000, or 3.8%, of all deaths across the 54 nations in the study.
Researchers now believe that periods of moderate or vigorous physical activity might not be enough to undo the detrimental effects of extended sitting. While researchers found that sitting contributed to all-cause mortality, they also estimated the impact from reduced sitting time independent of moderate to vigorous physical activity. "It was observed that even modest reductions, such as a 10% reduction in the mean sitting time or a 30-minute absolute decrease of sitting time per day, could have an instant impact in all-cause mortality in the 54 evaluated countries, whereas bolder changes (for instance, 50% decrease or 2 hours fewer) would represent at least three times fewer deaths versus the 10% or 30-minute reduction scenarios. Although sitting is an intrinsic part of human nature, excessive sitting is very common in modern societies. Sedentary behavior is determined by individual, social, and environmental factors, all strongly influenced by the current economic system, including a greater number of labor-saving devices for commuting, at home and work, and urban environment inequalities that force people to travel longer distances and live in areas that lack support for active lifestyles."
The results of this analysis show that reducing sitting time, even by a small amount, can lead to longer lives, but lessening time spent in chairs may also prompt people to be more physically active in general. "Although sitting time represents a smaller impact compared with other risk factors, reducing sitting time might be an important aspect for active lifestyle promotion, especially among people with lower physical activity levels. In other words, reducing sitting time would help people increase their volumes of physical activity along the continuum to higher physical activity levels."