According to a recent study published in the British Journal of Sports Medicine conducted by researchers at Griffith University in Australia, being as active as the 25% of the American population who do the most physical activity can extend life by at least 5 years.
It has long been known that physical activity is good for health, however, estimates of how many real benefits can be obtained from practicing a certain amount of physical activity are contradictory, both for individuals and for the population as a whole.
This latest study, rather than relying on survey responses as is often done, used wearable accelerometers to accurately monitor current levels of physical activity.
"I wondered how physical activity would translate into longevity and how much extra life could a single hour of walking bring," explained Lennert Veerman, professor of public health in Griffith's Faculty of Medicine and Dentistry.
How was the study conducted?
The authors used data on physical activity obtained through accelerometers worn (for at least 10 hours over four or more days) by adults aged 40 and older who participated in the National Health and Nutrition Examination Survey from 2003 to 2006.
The team then constructed a mortality table, a way of showing the probabilities of populations living or dying at a given age.
This mortality table was based on mortality data from the National Center for Health Statistics for 2017, which the authors assumed to be related to activity levels from 2003-2006.
Based on this information, the authors made a projection of how many people in the 2019 US population would survive over the coming years, depending on their activity levels and how much extra life they could gain by increasing them.
The data was organized into indices. The researchers calculated that being as active as the active quarter of the population would lead to a loss of 5.8 years in life expectancy for men and women.
However, if all Americans over the age of 40 were as active as the top quarter of them, life expectancy would increase by 5.3 years.
Total activity levels in the lowest quartile were equivalent to walking for 49 minutes at about 3 miles per hour per day.
The total activity levels at the second, third, and fourth highest value were equivalent to 78, 105, and 160 minutes, respectively.
The team also investigated what the potential benefits might be at an individual level rather than a population level, finding that if less active people did just less than two hours of extra physical activity per day, they could extend their lives by up to 11 years.
Big benefits for those who are less active
It is precisely those who are least active who have the greatest potential for improved health. “If you are very active, you are in that top quartile of the value and an extra hour of walking may not make much difference because, in a sense, you have already maximized the benefits,” said Lennert Veerman.
"If instead, that quarter of the least active population over 40 increased its activity level until it reached that practiced by the most active quarter, it could live on average about 11 years longer: it could be any type of exercise, but it would be more or less equivalent to about three hours of walking a day."
Experts advise taking advantage of every good moment to move and take a few extra steps: make phone calls while walking, take the stairs instead of the elevator, get off the bus or subway a few stops before school or work to make the last move on foot. Every opportunity is good for improving your health.