While normal weight and overweight men saw benefits from aerobic fitness, obese men were seen not to receive them in a study in Sweden. Photo by Robert Kneschke/Shutterstock
UMEA, Sweden, Dec. 21 (UPI) -- The authors of a new study say they have disproved the "fat but fit" notion after finding in a large study that obesity cancels out the benefits of being at high aerobic fitness.
Researchers at Umeå University in Sweden sought to find whether the negative health effects of obesity could be canceled out by increasing fitness levels, based on both being associated with death at older ages.
The study analyzed data on 1.3 million Swedish men followed from 1969 to 1996, with aerobic fitness measured by an electrically braked cycle test and causes of death tracked using Swedish national registers.
Researchers found, based on a mean follow-up of 29 years, 44,301 people died, with men in the highest fifth of aerobic fitness showing a 48 percent lower risk of death from any cause, as compared to the lowest fifth of men.
While the strongest associations seen for death were alcohol and narcotics abuse, risks associated with weight and fitness were similar, the researchers reported. Aerobic fitness was associated with reduced risk for death in normal and overweight men and the benefits from fitness were lower in obese men. Unfit normal-weight men also were seen to have a 30 percent lower risk of death from any cause than obese men.
A link was also found between low aerobic fitness and death from trauma, which Peter Nordström, a researcher at Umea University, said researchers could only speculate the cause, noting in a press release that "genetic factors could have influenced these associations given that aerobic fitness is under strong genetic control."
The study is published in the International Journal of Epidemiology.