Exercising regularly, such as brisk walking, helps people live longer than those who do not engage in physical activity in their spare time, even if they are overweight.

This finding came from a team of international experts led by Steven Moore, from the National Cancer Institute in Bethesda, USA, and was published in PLOS Medicine. The research coincides with a previous study which indicated that physical activity increases life expectancy and can help smokers increase their life span by 3.7 years.

The authors explained why the new study is significant. They said, "This finding 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 Swedish and American experts analyzed data on over 650,000 people aged 40 and older in a combined examination of 6 long-term reports (5 from the U.S. and one from Swedin). The data included details on leisure time physical activities and body mass index (BMI).

Results showed that leisure time exercise at a level comparable to brisk walking for up to 75 minutes per week was linked to an average increase in life expectancy of 1.8 years compared to people who did not do any physical activity.

The World Health Organization (WHO), on the other hand, suggests that physical activity should be at least 150 minutes of brisk walking per week. When subjects performed the recommended amount, their life expectancy was 3.4 to 4.5 years longer than people not exercising.

When the subgroups of males and females, high school and college graduates, and blacks and whites were examined one by one, increased leisure time physical activity continued to be associated with longer life span.

The research demonstrated that a lower amount of exercise was linked to a shorter life expectancy, regardless of BMI. However, a person who was physically active and had an average weight, or a BMI of 18.5 to 24.9, had a gain of 7.2 years of life compared to those who were inactive and obese class II, or had a BMI of 35 or higher.

Results also showed that normal weight people who did not exercise had 3.1 fewer years of life compared to those who were active and obese class I, or a BMI of 30 to 34.9.

It is important to find the time to add even a little amount of physical activity into your schedule, just 75 minutes of walking per week, the authors pointed out, because it may increase your life span.

The team concluded:

"Physical activity above the minimal level - at recommended levels, or even higher - appears to increase longevity even further, with the increase in longevity starting to plateau at approximately 300 minutes of brisk walking per week.

Finally, a lack of leisure time physical activity when combined with obesity is associated with markedly diminished life expectancy."

Written by Sarah Glynn