4. Discussion
fatigue
To our knowledge, this is the first study investigating the effect of short-term L-citrulline supplementation on respiratory muscles’ performance, fatigue, and oxygenation in older persons. We hypothesized that L-citrulline supplementation for seven days would increase NOIn a previous investigation, we reported no positive effect of acute L-citrulline supplementation on sternocleidomastoid muscle oxygenation and respiratory performance in healthy young individuals [