Protein2026-06

Effect of protein supplementation on cardiorespiratory fitness with aerobic training in chronic stroke: A multicenter randomized controlled trial.

Lin Yen-Nung, Viswanathan Anand, Ogawa Elisa F, Knuiman Pim et al. — International journal of stroke : official journal of the International Stroke Society

Summary

This study investigated whether protein supplements could further improve heart and lung fitness in chronic stroke patients undergoing aerobic exercise. Researchers found that while exercise significantly boosted fitness for all participants, adding extra protein didn't provide a noticeable additional benefit for heart and lung function compared to a placebo. However, the protein group did show some minor improvements in overall physical performance and body fat over a longer period.

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Key points

Protein supplements did not significantly enhance heart and lung fitness (cardiorespiratory fitness) in chronic stroke patients doing aerobic exercise.
Both the protein and placebo groups experienced significant improvements in fitness and physical ability due to the aerobic training itself.
The protein group showed slightly better long-term physical performance and a small reduction in body fat, but not better heart and lung fitness.
This suggests that for improving heart and lung fitness in this population, consistent exercise may be more impactful than additional protein supplementation.

What the study looked at

This research investigated if protein supplements, when combined with aerobic exercise, could further enhance heart and lung fitness, also known as cardiorespiratory fitness, in individuals living with chronic stroke. The study was a randomized controlled trial involving 114 adults who had experienced a stroke and were able to walk. Participants were divided into two groups: one received a protein supplement, and the other an identical-looking, calorie-matched placebo. Both groups completed 30 supervised aerobic training sessions over 10 weeks. The main finding was that both groups significantly improved their heart and lung fitness simply by doing the aerobic exercise. However, the protein supplement did not lead to any additional improvement in this primary measure compared to the placebo. While protein didn't boost heart and lung fitness, the protein group did show slightly better overall physical performance and a small reduction in body fat at later check-ups.

Dietary takeaway

This study suggests that for stroke survivors engaging in aerobic exercise, the exercise itself is the key driver for improving heart and lung fitness, and adding protein supplements may not offer extra benefits for this specific outcome. While protein is crucial for muscle health and recovery, focusing on consistent exercise might be more impactful for cardiorespiratory fitness in this context. Remember, this is one study, and individual dietary needs and responses can vary significantly.

Abstract

BACKGROUND: Decreased cardiorespiratory fitness (CRF) is prevalent in stroke patients, and aerobic training can improve CRF in this population. Protein supplementation has been proposed as a strategy to enhance exercise adaptations by promoting muscle protein synthesis, reducing muscle loss, and improving physical function. However, the potential of protein supplementation to further improve CRF during aerobic training among stroke patients remains unclear. This study aims to evaluate the effect of protein supplementation on CRF and physical performance in patients with chronic stroke undergoing aerobic training. METHODS: This multicenter, participant- and assessor-blinded, randomized clinical trial enrolled 114 ambulatory adults with chronic stroke at four teaching hospitals. Participants were randomized to receive protein supplementation (n = 58) or an isocaloric carbohydrate placebo (n = 56) during 30 supervised aerobic training sessions over 10 weeks. The primary outcome was the change in peak oxygen consumption (V̇Opeak, mL/kg/min) at 11 weeks. Secondary outcomes included CRF-related measures, body composition (total lean and fat mass), and physical performance (Short Physical Performance Battery (SPPB), Physical Performance Test, Berg Balance Scale, and Timed Up-and-Go test). RESULTS: Participants had a mean age of 57.2 years, 30% were women, and 87% completed the primary outcome assessment. At the 11-week follow-up, V̇Opeak increased by 1.7 mL/kg/min (95% CI: 1.0-2.4) in the protein group and 1.6 mL/kg/min (95% CI: 0.9-2.3) in the placebo group, with no between-group difference (mean difference, 0.1 mL/kg/min; 95% CI: -0.8 to 1.1; = 0.43). Both groups showed improvements in most CRF-related and physical performance measures. At 20 weeks, the protein group demonstrated greater SPPB improvement (mean difference, 0.7 points; 95% CI: 0.1-1.3; = 0.03) and lower fat mass at 11 weeks (mean difference, -0.6 kg; 95% CI: -1.2 to -0.06; = 0.04). CONCLUSIONS: Protein supplementation during aerobic training did not significantly enhance CRF compared with an isocaloric placebo. These findings warrant further investigation in populations with a broader range of baseline protein intake.

View on PubMed →DOI: 10.1177/17474930251403727