Increased exercise capacity reduces the risk of death in African-American and Caucasian men, researchers reported in Circulation: Journal of the American Heart Association.
The government-supported Veterans Affairs study included 15,660 participants and is the largest known to assess the link 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. Certainly, one does not need to be a marathon runner. This is the message that we need to convey to the public,” 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.
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) and also examined whether racial differences in exercise capacity influence the risk of death. Veterans were tested by a standardized treadmill test to assess exercise capacity between May 1983 and December 2006 at Veterans Affairs medical centers in Washington, D.C., and Palo Alto, Calif. The men were 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. Technically, a MET is equivalent to oxygen consumption of 3.5 milliliters per kilograms of body weight per minute. One MET represents the amount of oxygen the person uses at rest. Anything above one MET represents work. The higher the MET level achieved, the more fit the individual.
Based on this concept, 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
- 2,261 were “very highly fit,” achieving more than 10 METs.
The study found that “highly fit” men had half the risk of death 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.