Exercise won't just help your blood pressure or cholesterol readings. It could also extend your life, found a new study, and you don't have to be thin to reap benefits.

The researchers looked at the results of six long-term studies that included information on BMI readings and levels of physical activity for more than 630,000 people over the age of 40 and followed participants for an average of 10 years.

Results, published today in the journal PLOS Medicine, revealed that people who did the equivalent of up to 75 minutes of brisk walking each week boosted their life expectancies by nearly two years compared to those who didn’t exercise at all.

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When people exercised for 2.5 to five hours each week, expected lifespans improved by about three and a half years. Two and a half hours per week is the amount recommended by the World Health Organization.

Beyond five hours, benefits begin to plateau. When people put in 7.5 of exercise per week, they gained an expected 4.5 additional years.

Exercise-induced improvements in expected lifespans were greatest for people whose BMIs put them in the normal range. But even obese people benefitted from moderate amounts of activity.

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These findings "may help convince currently inactive persons that a modest physical activity program is 'worth it' for health benefits, even if it may not result in weight control," the researchers wrote. "Both a physically active lifestyle and a normal body weight are important for increasing longevity."

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