The Effects of Short Term L-Citrulline Supplementation on Wave Reflection Responses to Cold Exposure With Concurrent Isometric Exercise

Supplementation with L-citrulline (L-cit) has shown attenuating effects on blood pressure (BP) and pulse-wave-reflection responses (augmentation index (AIx)) to local exposure to cold, but the potential cardiopr otective effects of L-cit during whole-body cold exposure with concurrent exercise are poorly understood. We hypothesized that L-cit would attenuate the BP and AIx responses to cold exposure and isometric handgrip (IHG) exercise. Methods Sixteen healthy males with a mean age of 23 ± 3 y ears volunteered for a study of the effect of L-cit on the BP and AIx responses to cold expo sure and IHG exercise. Experiments were conducted inside an environmental chamber in cold conditions (4 oC). Radial waveforms were obtained in duplicates and averaged through applanation tonometry. After 5 minutes of measurements made at rest in the supine position (RES), after the finalization of the exercise about the subjects were evaluated in non exercise condition that were basically the same as the RES. After initial measurements in cold conditions, subjects were randomized to receive either a placebo (Maltodextrin, PL) or L-cit (100 mg/ kg) for 14 days, followed by a 14-day washout period and then a 14-day regimen of the other agent. Subjects were re-evaluated after each treatment period. r esults At RES, there was a significant treatment-by-time interaction for brachial systolic BP (BSBP; P < 0.01), aortic systolic BP (ASBP; P < 0.01), and AIx (P < 0.05), such that L-cit decreased BSBP (–11 ± 2 mm Hg; P < 0.01), ASBP (–10 ± 2 mm Hg; P < 0.05), and AIx (–2 ± 2%; P < 0.05) as compared with their respective values before the intervention. During IHG, BSBP, ASBP, and AIx were increased (P < 0.05) as compared with their values at RES, but these responses were unaffected by either of the study treatments. conclusions L-citrulline may be a feasible adjuvant treatment for decrease the BP and AIx responses induced by cold. Further research is warranted to evaluate the impact of cold exposure and exercise on cardiovascular risk in clinical populations.