The health risks associated with sitting for eight or more hours a day -- whether at work, home or commuting -- can be eliminated with an hour or more of physical activity a day, according to a study from an international team of researchers.
Recent estimates suggest that more than 5 million people die globally each year as a result of failing to meet recommended daily activity levels. A typical day for many people is driving to work, sitting in an office, driving home and watching TV. Current physical activity guidelines recommend that adults do at least 150 minutes of moderate intensity exercise per week.
In an analysis published today in The Lancet that draws together a number of existing studies, an international team of researchers asked the question: if an individual is active enough, can this reduce, or even eliminate, the increased risk of early death associated with sitting down?
The researchers found that 60 to 75 minutes of moderate intensity exercise per day were sufficient to eliminate the increased risk of early death associated with sitting for over eight hours per day. However, as many as three out of four people in the study failed to reach this level of daily activity. (Moderate intensity exercise was defined as equating to walking at 3.5 miles/hour or cycling at 10 miles/hour)
The greatest risk of early death was for those individuals who were physically inactive, regardless of the amount of time sitting -- they were between 28% and 59% more likely to die early compared with those who were in the most active quartile -- a similar risk to that associated with smoking and obesity. In other words, lack of physical activity is a greater health risk than prolonged sitting.
"For many people who commute to work and have office-based jobs, there is no way to escape sitting for prolonged periods of time. For these people in particular, we cannot stress enough the importance of getting exercise, whether it's getting out for a walk at lunchtime, going for a run in the morning or cycling to work. An hour of physical activity per day is the ideal, but if this is unmanageable, then at least doing some exercise each day can help reduce the risk," says Professor Ulf Ekelund from the Medical Research Council Epidemiology Unit at the University of Cambridge.