Gary R. Hunter

Objective This study investigated whether combined aerobic and resistance training in older women leads to metabolic adaptation. Methods A total of 80 women (64 White individuals; BMI: 30.0 [4.4] kg/m 2 ; age: 64.8 [3.5] years) followed 32 weeks of aerobic and resistance training. Body weight/composition (dual‐energy X‐ray absorptiometry) and resting metabolic rate (RMR; indirect calorimetry) were measured at baseline, week 16, and week 32. Metabolic adaptation was defined as significantly lower measured versus predicted RMR. A regression model to predict metabolic adaptation was developed that included race, age, baseline fat‐free mass, RMR and respiratory quotient, and changes in net submaximal oxygen consumption after different tasks. Results There was significant metabolic adaptation at week 16 (−59 [136] kcal/d, p = 0.002), following a 640‐kcal/wk energy loss (−0.7 [2.6] kg of weight loss). In 53 women with complete data, metabolic adaptation was seen both at week 16 (−64 [129] kcal/d, p = 0.001) and at week 32 (−94 [127] kcal/d, p < 0.001). Metabolic adaptation at week 16 was predicted by race, age, baseline fat‐free mass, RMR and respiratory quotient, and change in net oxygen consumption of walking ( R 2 adjusted = 0.90, p < 0.001). Similar results were seen at week 32. Conclusions In older women with overweight and obesity, a minimal energy deficit induced by aerobic and resistance exercise is associated with metabolic adaptation at the level of RMR.