There may be a good reason to approach the sexes differently when designing exercise programs for obese clients. A study published in the July issue of Chest (2005; 128 [1], 256–62) found that severely obese men were more carbohydrate intolerant and had less physical endurance than severely obese women. This conclusion led researchers to believe that gender plays a strong role in physical fitness and in a person’s ability to metabolize carbohydrates.

Researchers from Delft-Voorburg and Groningen, the Netherlands, performed exercise capacity tests on 22 men and 34 women scheduled for bariatric surgery. American Diabetes Society guidelines were used to evaluate patients for carbohydrate intolerance. Results showed that all participants were similar in age and body mass index, but 59% of the men had overt diabetes or were carbohydrate intolerant, as opposed to only 35% of the women.

Further assessments revealed that women performed better on exercise endurance and related lung-capacity tests. Researchers explained this by pointing out that men tend to have upper-body fat, whereas women typically accumulate fat in the lower body. The difference in fat distribution may lead to decreased lung capacity in men.

“Carbohydrate intolerance . . . may lead to a buildup of fat deposits on muscle tissue, which can cause a person to gain weight and, eventually, impair physical endurance,” said study co-author Emile F. Dubois, MD, PhD, FCCP. “It appears that carbohydrate intolerance is more common in obese men, which would cause them to be less physically fit than obese women.”