An overweight man Reuters

Lack of exercise, or a sedentary lifestyle, is far more deadly than obesity, scientists have found. Even a 20-minute brisk walk every day can reduce the risk of death by 30 percent.

The risk reduction was seen in normal, overwieght and obese people. The research, led by Ulf Ekelund, a senior investigator scientist in the Medical Research Council Epidemiology Unit at the University of Cambridge, estimates that eradicating physical inactivity in the population would reduce deaths twice as much as if obesity is eradicated.

The report, published in the American Journal of Clinical Nutrition, says that from the perspective of public health, it is at least as important to increase physical activity as it is to reduce obesity, if not more so.

For any type of body weight, going from inactive to active can significantly reduce the chances of premature death. Reducing obesity is not at odds with performing physical exercise either since both are paths to a leaner, fitter body.

Data from 334,000 men and women were collected for the study. The study followed the subjects over a 12-year period measuring height, weight, waist and self-reported physical activity levels. It was found that even a moderate amount of physical activity, relative to no activity at all, was enough to reduce the risk of premature death.

It is estimated that burning 90 to 110 calories a day could reduce the risk of early death by 16 to 30 per cent. While the effect of moderate exercise was greatest among normal weight people, even obese individuals and those who are overweight experienced improvement in their health.

The resarchers found from data on deaths in Europe that 337,000 of the 9.2 million deaths of European men and women were linked to obesity and suggest that twice that number of deaths could be linked to lack of physical exercise.

The human body is designed to move. Aerobic exercises ignite the body's immune system, improves mental function, boosts energy, strengthens muscles and bones, and reduces the risk of chronic diseases such as heart disease, cancer and diabetes, the researchers said.

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