If you are among the 25 percent of Americans doing the least amount of physical exercise, long daily walks could increase life expectancy by almost 11 years, a new study found.
Researchers at the Griffith University School of Medicine and Dentistry in Gold Coast, Australia, collected life-table data from the U.S. Census Bureau and mortality data from the CDC’s National Centre for Health Statistics and ran these through a predictive model to determine life expectancy based on levels of physical activity.
Results from the study, published on Nov. 14, showed significantly higher increases in life expectancy compared to previous studies—at 10.9 years, much higher than what was previously understood.
A 2012 study attributed a maximum life expectancy gain of 4.2 years for regular physical exercise, whereas a 2002 Canadian study concluded a maximum of 6.9 extra years of life.
The researchers attributed this difference to the manner in which physical activity was logged; whereas previous studies relied on self-reported data, the Griffith University team relied on device-based measures.
The examined population was divided into four quartiles according to their levels of physical activity, from least active to most active.
The results found Americans over the age of 40 could live on average an extra 5.3 years if they were all as active as the top 25 percent of the population, bringing the average life expectancy to 83.7 years.
The greatest gain was observed in those most deprived of physical activity. If the least active quartile of Americans wants to enjoy the same health conditions as the most active quartile, they can achieve it with daily 2-hour walks (111 minutes to be exact), or an equivalent amount of exercise.
Additionally, a half-hour walk can shift people from the least active quartile into the second-least active quartile, where an extra hour’s walk could add 6.3 hours of additional life expectancy.
Extending daily walks by yet another 30 minutes brings them into the second most active quartile of Americans, with each hour of walking adding almost three hours to life, the study concludes.
“Our results suggest that the impact of low [physical activity] as a risk factor for all-cause mortality is comparable to that of smoking and potentially greater than that of hypertension,” the researchers said.
A 2013 UK-based study of a million women showed that smokers lose at least 10 years of lifespan, or three hours and 40 minutes of life per pack of 20 cigarettes.
“There is a strong need to communicate these new estimates to decision-makers and clinicians,” the researchers concluded. “Our study also highlights that the costs of physical inactivity are much larger than previously estimated.”
According to the U.S. Department of Health and Human Services, only 26 percent of men and 19 percent of women get enough activity to meet aerobic and muscle-strengthening guidelines.
According to the department’s Physical Activity Guidelines for Americans, this lack of physical activity is linked to $117 billion in annual health care costs and about 10 percent of premature mortality.
So get up, put on your shoes, and enjoy a walk!