Neither pre-sleep nor post-exercise protein consumption influences resistance exercise training adaptations in older adults

Abstract

Purpose: Limited data exists that compare pre-sleep versus post-exercise protein intake during resistance exercise training (RET) in older adults. This study examined whether 40 g of protein consumed post-exercise (PRP) or pre-sleep (PSP) enhances muscle thickness (MT) and strength compared to RET alone (RETO) in older men. Methods: Thirty untrained older men (65.7 ± 4.0 yrs) completed 12 weeks of supervised RET (2×/week) and were randomized to PRP (n = 9), PSP (n = 11), or RETO (n = 10). MT of the vastus lateralis (VL), rectus femoris (RF), and vastus intermedius (VI) and 1-repetition maximum (1-RM) for leg and chest press were assessed at weeks 0, 6, and 12. Results: VL (0 to 12 weeks: + 0.16 cm, 95% C.I. [0.06, 0.25]), RF (0 to 12 weeks: + 0.13 cm, 95% C.I. [0.03, 0.23]), and VI MT (0 to 12 weeks: + 0.18 cm, 95% C.I. [0.05, 0.31]) and chest press (0 to 12 weeks: + 10.9 kg, 95% C.I. [5.50, 16.3]) and leg press (0 to 12 weeks: + 28.3 kg, 95% C.I. [19.63, 37.1]) 1-RM increased (p < 0.050) with no group differences. Conclusion: Consuming 40 g of protein post-exercise or pre-sleep did not enhance RET-induced improvements in muscle thickness or strength in older adults with adequate baseline protein intake (≥1.0 g/kg/day). RET alone elicited significant gains, emphasizing that adherence to training and meeting daily protein requirements are more critical than timing strategies for untrained older adults. ClinicalTrials.gov identifier: NCT05922475, 06/23/2023, retrospectively registered.