ADA: Aerobic Exercise Burns Fat All on Its Own
CHICAGO — In obese teenage girls, both aerobic exercise and resistance training were effective at reducing total fat — even if the girls didn’t cut calories or lose weight, researchers found.
Aerobic exercise was also associated with reductions in visceral obesity and liver fat and improvements in insulin sensitivity, SoJung Lee, PhD, of Pittsburgh Children’s Hospital, reported here at the American Diabetes Association meeting.
Previous research by Lee and colleagues has shown that increasing physical activity — without caloric restriction — is effective in reducing total, fat, visceral obesity, and liver fat in obese adolescent boys. So the team wanted to find out if the same strategy is helpful for teenage girls as well.
The study involved 40 obese adolescent girls with BMIs in the 95th percentile or greater for their age. They were randomized to 3 months of aerobic exercise, with three 60-minute sessions on a treadmill a week; resistance exercise consisting of working out on a weigh machine three times a week, for 60 minutes a session; or a sedentary control group.
The teens were allowed to continue to eat as before.
Compared with controls, body weight dropped 1.3 kg in the aerobic exercise group and 0.3 kg in the resistance training group (P>0.1).
Despite the absence of weight loss, total fat decreased 1.5% in the aerobic exercise group and 1.4% in the resistance training group compared with controls (P<0.05 for both).
Visceral fat dropped 19% and lipid fat decreased 43% in the aerobic arm compared with the control arm (P<0.05). Also, insulin sensitivity improved 23% in the girls who did aerobics compared with the sedentary teens (P<0.05).
There was no significant change in any of these parameters in the resistance training group.
Patricia Gatcomb, MSN, a nurse practitioner at Yale University, said she was surprised at the lack of weight loss given the increase in the exercise arms.
To achieve clinically meaningful improvements in fat or insulin sensitivity levels, the intervention needed to be longer, she added.
Lee and Gatcomb reported no financial conflicts of interest.
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