L-Citrulline Supplementation Attenuates Aortic Pressure and Pressure Waves During Metaboreflex Activation in Postmenopausal Women.

Postmenopausal women have augmented pressure wave responses to low-intensity isometric handgrip exercise (IHG) due to an overactive metaboreflex (postexercise muscle ischemia, PEMI), contributing to increased aortic systolic blood pressure (SBP). Menopause-associated endothelial dysfunction via arginine (ARG) and nitric oxide deficiency may contribute to exaggerated exercise SBP responses. L-Citrulline supplementation (CIT) is an ARG precursor that decreases SBP, pulse pressure (PP), and pressure wave responses to cold exposure in older adults. We investigated the effects of CIT on aortic SBP, PP, and pressure of forward (Pf) and backward (Pb) waves during IHG and PEMI in 22 postmenopausal women. Participants were randomized to CIT (10g/day) or placebo (PL) for 4-weeks. Aortic hemodynamics were assessed via applanation tonometry at rest, 2-min of IHG at 30% of maximal strength, and 3-min of PEMI. Responses were analyzed as change (Δ) from rest to IHG and PEMI at 0 and 4 weeks. CIT attenuated ΔSBP (-9 ± 2 vs -1 ± 1 mmHg, P = 0.006), ΔPP (-5 ± 2 vs 0 ± 1 mmHg, P = 0.03), ΔPf (-6 ± 2 vs -1 ± 1 mmHg, P = 0.01), and ΔPb (-3 ± 1 vs 0 ± 1 mmHg, P = 0.02) responses to PEMI vs. PL. The ΔPP during PEMI was correlated with ΔPf ( r = 0.743, p < 0.001) and ΔPb ( r = 0.724, p < 0.001). Citrulline supplementation attenuates the increase in aortic pulsatile load induced by muscle metaboreflex activation via reductions in forward and backward pressure wave amplitudes in postmenopausal women.