SAN FRANCISCO — Even moderate physical fitness appears to confer a significant survival benefit on men with type 2 diabetes, no matter what their body weight, according to Roshney Jacob-Issac, Ph.D.
Her retrospective study, presented at the annual meeting of the Endocrine Society, found an inverse association between mortality and increasing fitness, with normal- and overweight men gaining even more survival benefits as they reached the highest fitness levels. Although obese men didn't reap any extra survival benefit with the top fitness level, moderate fitness decreased their overall risk of death by 52%.
“Increasing physical fitness has a survival benefit in diabetes regardless of body mass index,” said Dr. Jacob-Issac of the Veterans Affairs Medical Center, in Washington.
Her retrospective study examined the link between all-cause mortality and exercise capacity in 2,690 men with type 2 diabetes, all of whom were referred for exercise tolerance testing at VA centers in Washington or Palo Alto, Calif. Nearly half of the men (1,196) were obese; 1,088 were overweight, and 406 had a normal BMI.
Peak work load, which was determined via a stress test, was estimated in metabolic equivalents (METs). One MET equals the energy expenditure at rest, or an oxygen consumption of 3.5 mL/kg per minute. Based on peak workload, individuals were categorized as low fit (5 or fewer METs), moderately fit (5.1-8 METs), or highly fit (more than 8 METs). All-cause mortality was assessed at a mean of 7 years.
Overall there were 762 deaths (172 in the normal-weight group, 334 in the overweight group and 256 in the obese group). After adjustment for age, cardiac medications, and cardiovascular disease risk factors, Dr. Jacob-Issac found a strong, graded relationship between increasing fitness and decreasing mortality in all three groups.
In those men with a normal body weight, moderate fitness conferred a 40% reduction in the risk of death and high fitness conferred a 60% risk reduction, compared with low fitness. In overweight men, the risk reduction was 40% for moderate fitness and 65% for high fitness, compared with low fitness.
Among obese men, moderate fitness conferred a 52% reduction in the risk of death, but being highly fit conferred no additional protection.
Dr. Jacob-Issac reported no conflict of interest related to the study.