A brisk 20-minute walk each day is enough to reduce an individual's risk of early death, say British researchers.
After analysing over 334,000 European men and women, they also found that twice as many deaths may be attributable to lack of physical activity compared with the number of deaths attributable to obesity.
"We found that just 20 minutes would make a difference. Physical activity has many proven health benefits and should be an important part of our daily life," said professor Ulf Ekelund from the Medical Research Council (MRC) epidemiology unit at University of Cambridge.
For this, researchers analysed data across Europe participating in the European Prospective Investigation into Cancer and Nutrition (EPIC) Study.
Over an average of 12 years, the researchers measured height, weight and waist circumference and used self-assessment to measure levels of physical activity.
The researchers found that the greatest reduction in risk of premature death occurred in the comparison between inactive and moderately inactive groups, judged by combining activity at work with recreational activity.
"Doing exercise equivalent to just a 20 minute brisk walk each day would take an individual from the inactive to moderately inactive group and reduce their risk of premature death by between 16-30 percent," the authors noted.
The impact was greatest among normal weight individuals but even those with higher BMI saw a benefit.
Using the most recent available data on deaths in Europe, the team estimated that 337,000 of the 9.2 million deaths amongst European men and women were attributable to obesity.
However, double this number of deaths (676,000) could be attributed to physical inactivity.
"Encouraging people to make small but achievable changes in physical activity can have significant health benefits and may be easier to achieve and maintain," added professor Nick Wareham, director of the MRC Unit.
The results were published in the American Journal of Clinical Nutrition.
