Even a moderate amount of exercise can dramatically prolong a man's life, new research on middle-aged and elderly American veterans reveals.
The government-sponsored analysis—the largest such study ever—found that a regimen of brisk walking 30 minutes a day at least four to six days a week was enough to halve the risk of premature death from all causes.
"As you increase your ability to exercise-increase your fitness-you are decreasing in a step-wise fashion the risk of death," said study author Peter Kokkinos, PhD, director of the exercise testing and research lab in the cardiology department of the Veterans Affairs Medical Center in Washington, D.C.
That conclusion applies more or less equally to white and black men, regardless of their prior history of cardiovascular disease. This evened the playing field, he said, giving him "great confidence" in the results, published in Circulation.
Dr. Kokkinos and his team reviewed information gathered by the VA from 15,660 black and white male patients treated either in Palo Alto, California, or in Washington, D.C.
The men ranged in age from 47 to 71 and had been referred to a VA medical facility for a clinically prescribed treadmill exercise test. All participants were asked to run until fatigued, at which point the researchers then recorded the total amount of energy expended and oxygen consumed.
The numbers were then crunched into "metabolic equivalents," or METS. In turn, the researchers graded the fitness of each man according to his MET score, ranging from "lowfit" (below 5 METS) to "very high-fit (above 10 METS).
By tracking fatalities, Dr. Kokkinos and his colleagues found that for both black and white men it was their fitness level, rather than their age, blood pressure or body-mass index, that was most strongly linked to their future risk for death.
Every extra MET point conferred a 14% reduction in the risk for death among black men, and a 12% reduction among whites. Among all participants, those categorized as moderately fit" to 7 METS) had about a 20% lower risk for death than "low-fit men. "High-fit" men (7.1 to 10 METS) had a 50% lower risk, while the "very high-fit" (above 10 METS) cut their odds of an early death by 70%.
"The point is, it takes relatively little exercise to achieve the benefit we found," noted Dr. Kokkinos. "Approximately two to three hours per week of brisk walking per week. That's just 120 to 200 minutes per week. And this can be split up throughout the week, and throughout the day. So it's doable in the real world."
Alice H. Lichtenstein, DSC, director of the Cardiovascular Nutrition Lab at Tufts University's USDA Human Nutrition Research Center in Boston, agreed.
"What this finding demonstrates is that levels of physical activity that should be achievable by anyone can have a real benefit with respect to risk reduction," she said.
"What's really important to understand is that you don't need special clothes, special memberships, special equipment," added Dr. Lichtenstein, who is also former vice chair of the American Heart Association's nutrition committee. "It's something everyone can engage in And although we don't know from this research that this applies to women as well, there's no reason to suspect that it wouldn't."