L-Arginine Supplementation Did Not Impact the Rapid Recovery of Cardiovascular and Autonomic Function Following Exercise in Physically Active Healthy Males: A Triple-Blind Randomised Placebo-Controlled Crossover Trial

Abstract

Background and aims: Post-exercise recovery strategies include massage, low-intensity active exercise, thermal contrast, hydration, and nutritional and herbal approaches. These strategies aim to accelerate recovery, enhance performance, and optimise the physical training process. L-arginine (L-ARG) is the physiological precursor of nitric oxide (NO), a crucial mediator of vasodilation and the inhibition of platelet aggregation. A previous study reported that L-ARG supplementation could significantly reduce the systolic blood pressure (SBP) and diastolic blood pressure (DBP). This study aimed to investigate the effects of L-ARG on autonomic and cardiovascular recovery immediately following submaximal exercise.

Methods and results: Thirty-two healthy individuals were subjected to two experimental protocols. The first protocol included 60 min of rest, a treadmill warm-up, and load increments until reaching 80% of their maximum HR. Before this protocol, the subjects consumed 3 g of starch (placebo protocol). The second protocol was identical, but the subjects consumed 3 g of L-ARG. Heart rate recovery (HRR), heart rate variability (HRV), and blood pressure (BP) responses were assessed. No significant differences in HRR were found (p = 0.944) regarding the root mean square of successive differences in the RR interval (RMSSD30) of HRV (p = 0.562) or in the BP responses (mean arterial pressure (MAP), p = 0.687; pulse pressure (PP), p = 0.929) between the protocols.

Conclusions: L-ARG supplementation did not significantly alter immediate post-exercise autonomic recovery in healthy males.

Keywords: arginine; autonomic nervous system; exercise; nitric oxide and post-exercise recovery techniques.

Figure 1

Flowchart diagram.

Figure 2

Mean values and their respective standard deviations for heart rate recovery (HRR) (A) and root mean square of successive RR interval differences analysed in 30 s intervals (RMSSD30) (B) during exercise and recovery obtained from the placebo protocol (placebo) and the L-arginine protocol (arginine) are presented. Caption: 1 min: first minute of recovery; 2 min: second minute of recovery; bpm = beats per minute; M1 = 0–30 s, M2 = 30–60 s, M3 = 60–90 s, M4 = 90–120 s of recovery; ms = milliseconds. * Values indicate significant differences compared to exercise (p < 0.05).

Figure 3

Mean values and their respective standard deviations for pulse pressure (PP) (A) and mean arterial pressure (MAP) (B) at baseline and during recovery are presented for the placebo protocol (placebo) and the L-arginine protocol (arginine). Caption: 1 min: first minute of recovery; 3 min: third minute of recovery; mmHg = millimetres of mercury. * Values indicate significant differences compared to baseline (p < 0.05).