Frequency-dependent adaptations in energy expenditure, strength, mood, and inflammation following 16 to 32 weeks of combined aerobic and resistance training in older women

We have previously shown that 16 weeks of combined aerobic–resistance training in older women decreases non-exercise activity thermogenesis (NEAT) when performed 3 times/week, but not when performed once or twice weekly. To examine changes from weeks 16 to 32 in anthropometrics, body composition, fitness, cytokines, mood, and energy expenditure (EE) components among training frequencies in older women. Sedentary women (60–74 y) previously randomized to 1 + 1, 2 + 2, or 3 + 3 sessions/wk of supervised combined aerobic–resistance training continued the program from weeks 16 to 32. Total EE (TEE) (doubly labeled water), resting EE (REE) (indirect calorimetry), training-related EE (TREE) (validated estimates), NEAT = activity EE (AEE) − TREE (AEE = 0.9×TEE − REE), fat mass (FM), and fat-free mass (FFM) (DXA), V̇O₂max (treadmill), mood/fatigue, and serum cytokines were measured at weeks 16 and 32. Two-way repeated-measures ANOVA was used with Tukey posthocs. Fifty-seven women contributed anthropometry/fitness/cytokines; 44 contributed EE components. Weight decreased, whereas FM (kg and %), FFM, V̇O₂max, IL-6, CRP, TNF-α, fatigue, vigor and REE were unchanged. Bench- and leg-press strength increased across groups. Depression varied by group (lower in 3 + 3 vs. 2 + 2; P = 0.044). TEE differed between groups (P = 0.017; 2 + 2 > 1 + 1 and 3 + 3). TREE increased over time (P = 0.002) and differed by group (P < 0.001). NEAT showed a time-by-group interaction (P = 0.049), increasing only in 3 + 3 (P = 0.044). High-frequency (3 + 3) combined aerobic-resistance training was associated with increased NEAT between weeks 16–32, but not lower frequencies. However, the 2 + 2 group continued to have the highest NEAT overall.