Exercise reduces abdominal obesity independent of exercise intensity

1. Participation in an exercise program, regardless of the amount or intensity, was linked to a reduction in waist circumference and body weight in obese adults.

2. Higher exercise intensity was associated with improved 2-hour glucose level in obese adults.

Evidence Rating Level: 1 (Excellent)

Study Rundown: Most Americans have sedentary lifestyles, and physical inactivity is a major determinant of obesity. Current guidelines recommend regular exercise, but the benefits of the intensity of the exercise are unknown. This randomized clinical trial sought to determine the effects of different amounts and intensities of exercise on abdominal obesity and glucose tolerance in obese adults. During the 24-week study, obese subjects were all provided dietary recommendations at baseline and were randomly assigned to either control (no exercise) or one of three groups with differing exercise amounts and intensities. Compared to control, all exercise groups had significant reductions in waist circumference and body weight, but there were no significant differences observed amongst exercise groups. Improvements in Matsuda index and insulin levels were observed in the two groups burning the most calories per session, irrespective of exercise intensity. On the other hand, significant improvements in 2-hour glucose levels were only seen in the high-intensity, high-amount group. The generalizability of this study may be limited by the large number of participants lost to follow-up (27.7%). Overall, this study suggests that regular exercise of any intensity may be a viable option for clinicians to recommend to their patients to reduce abdominal obesity.

Click to read the study, published today in the Annals of Internal Medicine

Relevant Reading: Sprint interval and moderate-intensity continuous training have equal benefits on aerobic capacity, insulin sensitivity, muscle capillarisation and endothelial eNOS/NAD(P)Hoxidase protein ratio in obese men

In-Depth [randomized controlled trial]: This study randomly assigned participants to one of four parallel groups 1) control group, 2) low-amount, low-intensity exercise (LALI), 3) high-amount, low-intensity (HALI) and 4) high-amount, high-intensity (HAHI). All patients with conditions contraindicating exercise, those with diabetes and those who already participated in >2 regular exercise activities were excluded. Exercise amount was measured by the calories burned during a session (LA 180-300 vs. HA 360-600) and exercise intensity was measured by percentage of VO2 max (LI 50% vs. HI 75%). Waist circumference (in centimeters) was reduced by 3.1, 3.6 and 3.6 at week 16 and 3.9, 4.6, and 4.6 at week 24 for LALI, HALI and HAHI, respectively (p<0.001). Body weight decreased in all exercise group compared to control (p<0.001) though it did not differ between exercise groups (p≥0.20). Cardiorespiratory fitness was improved in all exercise groups at 24 weeks with the improvements observed for HAHI>HALI>LALI >control. Significant improvements in 2-hour glucose level were observed only at week 24 in the HAHI vs. control (p=0.026) and HAHI vs. LALI (p=0.030) comparisons.

Image: PD

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