Effect of Exercise Type During Intentional Weight Loss on Body Composition in Older Adults with Obesity

ObjectiveTo examine the long-term effects of exercise modality during weight loss on body composition and associations between body composition and physical function changes. MethodsTwo hundred forty-nine older adults (66.94.7 years, 71% women, 32% African American, BMI: 34.43.7 kg/m(2)) were randomized to weight loss (WL; n=82), WL plus aerobic training (WL+AT; n=86), or WL plus resistance training (WL+RT; n=81) for 18 months. Dual-energy x-ray absorptiometry-acquired body composition, 400-m walk time, and knee extensor strength were measured at baseline and at 6 and 18 months. ResultsTotal body mass loss was enhanced when WL was combined with exercise (WL: -5.7 +/- 0.7 kg, WL+AT: -8.5 +/- 0.7 kg, WL+RT: -8.7 +/- 0.7 kg; P<0.01). Total body fat mass loss was significantly greater in WL+AT (-6.8 +/- 0.6 kg, -16.4%) and WL+RT (-7.8 +/- 0.5 kg, -19.0%) than WL (-4.8 +/- 0.6 kg, -10.9%); both P<0.01. Lean mass loss was greatest in WL+AT (-1.6 +/- 0.3 kg, -3.1%) compared with WL+RT (-0.8 +/- 0.3 kg, -1.5%) or WL (-1.0 +/- 0.3 kg; -2.0%); both P0.02. Change in 400-m walk time was associated with change in fat mass (/SD=+6.1 s; P<0.01), while change in knee extensor strength was associated with change in lean mass (/SD=+1.6Nm; P<0.01). ConclusionsWL+RT results in less lean mass lost than WL+AT; WL plus exercise yields greater fat mass loss than WL alone.