Combined L-Citrulline Supplementation and Slow Velocity Low-Intensity Resistance Training Improves Leg Endothelial Function, Lean Mass, and Strength in Hypertensive Postmenopausal Women

Abstract

Hypertension is highly prevalent in postmenopausal women. Endothelial dysfunction is associated with hypertension and the age-related decreases in muscle mass and strength. L-citrulline supplementation (CIT) and slow velocity low-intensity resistance training (SVLIRT) have improved vascular function, but their effect on muscle mass is unclear. We investigated whether combined CIT and SVLIRT (CIT + SVLIRT) would have additional benefits on leg endothelial function (superficial femoral artery flow-mediated dilation (sfemFMD)), lean mass (LM), and strength in hypertensive postmenopausal women. Participants were randomized to CIT (10 g/day, n = 13) or placebo (PL, n = 11) alone for 4 weeks and CIT + SVLIRT or PL + SVLIRT for another 4 weeks. sfemFMD, leg LM and muscle strength were measured at 0, 4, and 8 weeks. CIT increased sfemFMD after 4 weeks (CIT: Δ1.8 ± 0.3% vs. PL: Δ−0.2 ± 0.5%, p < 0.05) and 8 weeks (CIT + SVLIRT: Δ2.7 ± 0.5% vs. PL + SVLIRT: Δ−0.02 ± 0.5, p = 0.003). Leg LM improved after CIT + SVLIRT compared to PL + SVLIRT (Δ0.49 ± 0.15 kg vs. Δ0.07 ± 0.12 kg, p < 0.05). Leg curl strength increased greater with CIT + SVLIRT compared to PL + SVLIRT (Δ6.9 ± 0.9 kg vs. Δ4.0 ± 1.0 kg, p < 0.05). CIT supplementation alone improved leg endothelial function and when combined with SVLIRT has additive benefits on leg LM and curl strength in hypertensive postmenopausal women.

L-Citrulline Supplementation Improves Arterial Blood Flow and Muscle Oxygenation during Handgrip Exercise in Hypertensive Postmenopausal Women

“…Moreover, although there was no change in aortic stiffness, we found that 4 weeks of CIT supplementation improved FMD by 1.6%, showing the clinical significance of a potential reduction in the risk of cardiovascular disease by approximately 19% [41]. Similarly, previous studies have reported the efficacy of CIT supplementation on endothelial function in postmenopausal women [30,42] but not on aortic stiffness [43,44]. Our findings suggest that oral CIT supplementation may lead to functional improvement in limb arteries by enhancing the ARG-NO pathway [30,31], despite no change in the structural property of the conduit arteries.…”

L-Citrulline supplementation attenuates aortic pressure and pressure waves during metaboreflex activation in postmenopausal women

“…CIT is an ARG precursor and can increase NO bioavailability and endothelial function. Recent findings from our laboratory showed that 4 and 8 weeks of CIT can improve endothelial function assessed via brachial and superficial femoral flow-mediated vasodilation through increases in ARG and NO bioavailability in hypertensive and obese postmenopausal women (20,21,41) . Moreover, our previous data demonstrated that CIT attenuates the acute increase in systemic arterial stiffness induced by sympathetic mediated vasoconstriction during PEMI and cold exposure (23) .…”

“…Moreover, our previous data demonstrated that CIT attenuates the acute increase in systemic arterial stiffness induced by sympathetic mediated vasoconstriction during PEMI and cold exposure (23) . Thus, the ability of CIT to attenuate aortic SBP, PP, Pf and Pb responses to metaboreflex activation may have occurred through reduced proximal aortic stiffness and increased peripheral vasodilatory capacity (20,41) . The impact of CIT on Pf may explain the observed aortic pulsatile load attenuation without affecting peripheral BP.…”

Benefits of Supplementation with L-arginine, Citrulline and Watermelon on Vascular and Metabolic Health

“…Previous studies did not use resistance training for exercise. However, Kang et al [ 9 ] employed resistance training for investigating the effects of CIT supplementation on superficial femoral FMD, leg lean mass measured by dual-energy X-ray absorptiometry, and leg muscle strength. They randomized participants to CIT or placebo for 8 weeks.…”