Acute effects of l-arginine intake on heart rate variability after a submaximal exercise test in healthy men: randomized clinical trial.
- 2025-08
- Nitric oxide : biology and chemistry 157
- Andrey Alves Porto
- Luana Almeida Gonzaga
- Rayana Loch Gomes
- Bruno M Candeloro
- Rodrigo Daminello Raimundo
- Luiz Carlos Marques Vanderlei
- Vitor Engrácia Valenti
- PubMed: 40389021
- DOI: 10.1016/j.niox.2025.05.003
Study Design
- Type
- Randomized Controlled Trial (RCT)
- Population
- 37 physically active males (18-30 years)
- Methods
- triple-blind, randomized, placebo-controlled, crossover trial; two treadmill exercise protocols: one following ingestion of 3 g of L-ARG and the other with placebo
- Blinding
- Triple-blind
- Duration
- acute (single dose, post-exercise recovery measured across 20 min)
l-arginine (L-ARG) is a semi-essential amino acid and a precursor for nitric oxide (NO) synthesis via endothelial nitric oxide synthase (eNOS). While NO has been implicated in autonomic modulation and vascular function, the effects of acute L-ARG intake on heart rate variability (HRV) after exercise remain unclear. This study aimed to assess the acute effects of L-ARG supplementation on HRV and cardiovascular recovery following submaximal aerobic exercise in healthy men. In a triple-blind, randomized, placebo-controlled, crossover trial, 37 physically active males (18-30 years) underwent two treadmill exercise protocols: one following ingestion of 3 g of L-ARG and the other with placebo. HRV and cardiovascular parameters (heart rate, systolic and diastolic blood pressure) were measured at baseline and across 20 min of post-exercise recovery. Time- and frequency-domain HRV indices were analyzed using validated algorithms. Two-way repeated measures ANOVA and post-hoc tests were applied (p < 0.05). Significant time effects were observed for HRV and cardiovascular variables across both protocols (p < 0.001), indicating physiological recovery. However, no statistically significant differences were found between the L-ARG and placebo conditions for any HRV or hemodynamic outcome. A trend toward faster vagal reactivation (rMSSD) was observed with L-ARG, but effect sizes were small and not clinically relevant. Acute supplementation with 3 g of l-arginine did not significantly influence HRV or cardiovascular recovery following submaximal aerobic exercise in healthy young men. These findings suggest limited autonomic effects of L-ARG in populations with high baseline HRV.
Research Insights
A trend toward faster vagal reactivation (rMSSD) was observed with L-ARG, but effect sizes were small and not clinically relevant.
- Effect
- Neutral
- Effect size
- Small
- Dose
- 3 g
Acute supplementation with 3 g of l-arginine did not significantly influence HRV or cardiovascular recovery following submaximal aerobic exercise in healthy young men.
- Effect
- Neutral
- Effect size
- Small
- Dose
- 3 g
no statistically significant differences were found between the L-ARG and placebo conditions for any HRV or hemodynamic outcome
- Effect
- Neutral
- Effect size
- Small
- Dose
- 3 g
no statistically significant differences were found between the L-ARG and placebo conditions for any HRV or hemodynamic outcome
- Effect
- Neutral
- Effect size
- Small
- Dose
- 3 g
no statistically significant differences were found between the L-ARG and placebo conditions for any HRV or hemodynamic outcome
- Effect
- Neutral
- Effect size
- Small
- Dose
- 3 g