Washington, Jan 23 : Researchers at the Veterans Affairs Medical Center in Washington, D.C. have reported that increased exercise reduces the risk of death in men, especially among African-Americans and Caucasians.
The study, which included 15,660 participants, is the largest known to assess the association between fitness and mortality.
"It is important to emphasize that it takes relatively moderate levels of physical activity, like brisk walking, to attain the associated health benefits," said Peter Kokkinos, Ph.D., lead author of the study and director of the Exercise Testing and Research Lab in the cardiology department at the Veterans Affairs Medical Center in Washington, D.C.
For the study, Professor Kokkinos and colleagues investigated exercise capacity as an independent predictor of overall mortality for African-American men (6,749) and Caucasian men (8,911). They also examined whether racial differences in exercise capacity influence the risk of death.
The men were tested by a standardized treadmill test to assess exercise capacity and encouraged to exercise until fatigued unless they developed symptoms or other indicators of ischemia. These individuals were then followed for an average of 7.5 years and death rates were recorded.
Researchers classified the subjects into fitness categories based on their treadmill performance, expressed as peak metabolic equivalents (METs) achieved. The higher the MET level achieved, the more fit the individual.
The researchers divided the participants into four categories: 3,170 men were 'low fit,' achieving less than 5 METs; 5,153 men were 'moderately fit,' achieving 5 to 7 METs; 5,075 were 'highly fit,' achieving 7.1 to 10 METs; and ,261 were 'very highly fit,' achieving more than 10 METs.
The researchers found that 'highly fit' men had half the risk of death as compared to 'low fit' men. Men who achieved 'very highly fit' levels had a 70 percent lower risk of death compared to those in the 'low fit' category.
For every 1-MET increase in exercise capacity (fitness), the risk for death from all causes was 13 percent for both African Americans and Caucasians.
"These findings are important for several reasons: First, we were able to quantify the health benefits per unit increase in exercise capacity. Second, this is the first study to provide information on physical activity and mortality in African Americans, information lacking until now," Kokkinos said.
"Keep in mind that death rates in African Americans are much higher when compared with Caucasians, in part because race and income negatively influence access to healthcare." he added.
"Our findings show that the risk of death is cut in half with an exercise capacity that can easily be achieved by a brisk walk of about 30 minutes per session 5-6 days per week," he added
The study is published in Circulation: Journal of the American Heart Association.