EFFECTS OF MODERATE AEROBIC EXERCISE ON THE ATTENUATION OF LEAN MASS LOSS DURING RAPID WEIGHT LOSS
Background: Obesity has become a severe issue in the United States, and gastric bypass surgery has been one of the most successful tools to combat the adverse consequences of this disease. The rapid weight loss associated with gastric bypass surgery is also associated with a loss of lean mass. Lean mass maintenance is necessary for both maintenance of basal metabolic rate and ambulation; therefore, the focus of many studies has been directed toward attenuating the loss of lean mass resulting from gastric bypass surgery. Previous studies on the subject have included aerobic exercise, resistance exercise, and a combination of the two with varying results; however, all past studies have been short term (less than 4 months). Purpose: The purpose of this study was to explore the effects of a long term (6 month) aerobic exercise program on lean mass and to determine if there were differences between the loss of lean mass in the arms and legs. It was hypothesized that the loss of lean mass would be attenuated by 6 months of exercise, and that the lean mass loss would be attenuated more in the lower body then upper body. Methods: Forty-seven obese, adult men and women having undergone gastric bypass surgery were randomized into 2 groups: control and exercise. Control group participants received typical care following surgery whereas exercise group participants were progressed to 4-5 days per week, 30-45 min per session (120-180 min per week) of moderate intensity aerobic exercise, 60-70% maximal heart rate. The 6 month intervention began 1-3 months post-gastric bypass surgery. Pre and post assessments were made using dual energy X-ray absorptiometry (DXA). 2-way repeated measures ANOVA was used to analyze tissue percent fat, tissue mass, fat mass, lean mass, total mass, and bone mineral content in the right side body and in segments of the right side of the body. Results: Mean weight loss over the 6-month intervention was 19.9% of body weight. The tissue % fat decreased 10.6% (SE of diff 1.5%) in the control group and 13.2% (SE of diff 1.4%) in the exercise group. Fat mass decreased 36.5% (SEM 3.1%) in the control group and 42.6% (SEM 3.7%) in the exercise group. Lean mass decreased 2.1 % (SEM 1.5%) in the control group and 3.0% (SEM 2.6%) in the exercise group. There were no significant between groups differences. Both groups decreased lean mass in the right upper arm (control group 0.3 kg SEM 0.1 kg; exercise group 0.4 kg SEM 0.1 kg). Lean mass in the right lower leg significantly decreased over time in the exercise group (0.1 kg SEM 0.05 kg); conversely, the control group maintained lean mass in the right lower leg. Conclusion: The results of this study suggest a 6 month moderate intensity aerobic exercise intervention that begins 1-3 months post-gastric bypass surgery does not attenuate the loss of lean mass resulting from gastric bypass surgery. Segmentally, exercise does not lessen the loss of lean mass in the upper arm, and actually results in a greater loss of lean mass in the lower leg as compared to the control. The loss of lean mass in the lower leg may be a result of biomechanical changes in walking patterns associated with weight loss.
Belanus, Greta. (January 2013). EFFECTS OF MODERATE AEROBIC EXERCISE ON THE ATTENUATION OF LEAN MASS LOSS DURING RAPID WEIGHT LOSS (Master's Thesis, East Carolina University). Retrieved from the Scholarship. (http://hdl.handle.net/10342/4299.)
Belanus, Greta. EFFECTS OF MODERATE AEROBIC EXERCISE ON THE ATTENUATION OF LEAN MASS LOSS DURING RAPID WEIGHT LOSS. Master's Thesis. East Carolina University, January 2013. The Scholarship. http://hdl.handle.net/10342/4299. July 17, 2018.
Belanus, Greta, “EFFECTS OF MODERATE AEROBIC EXERCISE ON THE ATTENUATION OF LEAN MASS LOSS DURING RAPID WEIGHT LOSS” (Master's Thesis., East Carolina University, January 2013).
Belanus, Greta. EFFECTS OF MODERATE AEROBIC EXERCISE ON THE ATTENUATION OF LEAN MASS LOSS DURING RAPID WEIGHT LOSS [Master's Thesis]. Greenville, NC: East Carolina University; January 2013.
East Carolina University