Washington D.C, Jul 28 : Turns out, just an hour of moderate activity a day is enough to counter all the negative impacts of sedentary behaviour.
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.
In an analysis that draws together a number of existing studies, the teamasked the question: if an individual is active enough, can this reduce, or even eliminate, the increased risk of early death associated with sitting down? In total the researchers analysed 16 studies, which included data from more than one million men and women.
The team grouped individuals into four quartiles depending on their level of moderate intensity physical activity, ranging from less than 5 minutes per day in the bottom group to over 60 minutes in the top.
Moderate intensity exercise was defined as equating to walking at 3.5 miles/hour or cycling at 10 miles/hour, for example.
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.
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 percent and 59 percent 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. Ulf Ekelund from the University of Cambridge said, "Our message is a positive one: it is possible to reduce - or even eliminate - these risks if we are active enough, even without having to take up sports or go to the gym." The researchers acknowledge that there are limitations to the data analysed, which mainly came from participants aged 45 years and older and living in western Europe, the US and Australia.
However, they believe that the strengths of the analysis outweigh these limitations. Most importantly, the researchers asked all included studies to reanalyse their data in a harmonized manner, an approach that has never before been adopted for a study of this size and therefore also provides much more robust effect estimates compared with previous studies.
The study is published in The Lancet..