Effects of protein supplementation on aerobic training-induced gains in cardiopulmonary fitness, muscle mass, and functional performance in chronic stroke: A randomized controlled pilot study

Background & aims The beneficial effects of protein supplementation on aerobic exercise-induced gains in patients with stroke are currently unknown. This study evaluated the feasibility and potential value of protein supplementation with aerobic exercise among stroke survivors. Methods This double-blinded randomized controlled pilot study included 20 ambulatory persons with chronic (>6 months) stroke randomly assigned to either the protein (PRO) or carbohydrate (CHO) group. All participants received three 40-min cycling ergometric training sessions a week for 8 weeks. Training intensity at 60%–80% heart rate reserve was determined using cardiopulmonary exercise pretests. Immediately before and after each session, the PRO group received a 20-g protein-rich supplement, and the CHO group received a 20-g calorie-matched carbohydrate-rich supplement. Outcomes included changes in body composition, cardiopulmonary capacity, and clinical functional performance. Results Those completing the protocol (n = 18) received 18–24 cycling training sessions, achieving target training intensity without major adverse effects. Of the two groups, the PRO group tended to obtain greater aerobic capacity (effect size [ES]>0.5 in every cardiopulmonary index), greater improvements in functional performance (0.25 < ES < 1.00 in various clinical tests), and greater total lean mass versus total fat mass (ES = 0.52). Conclusions Protein supplementation with aerobic exercise training tends to improve body composition, cardiopulmonary fitness, and function among persons with stroke. This study protocol is feasible, and future trials with larger sample sizes could confirm these results. Trial registration NCT03244527.