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 ischaemia, 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 twenty-two postmenopausal women. Participants were randomised to CIT (10 g/d) or placebo (PL) for 4 weeks. Aortic haemodynamics were assessed via applanation tonometry at rest, 2 min of IHG at 30 % of maximal strength, and 3 min of PEMI. Responses were analysed as change (Δ) from rest to IHG and PEMI at 0 and 4 weeks. CIT attenuated ΔSBP (−9 ± 2 v. −1 ± 1 mmHg, P = 0·006), ΔPP (−5 ± 2 v. 0 ± 1 mmHg, P = 0·03), ΔPf (−6 ± 2 v. −1 ± 1 mmHg, P = 0·01) and ΔPb (−3 ± 1 v. 0 ± 1 mmHg, P = 0·02) responses to PEMI v. 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.

Combined Citrulline and Glutathione Supplementation Improves Endothelial Function and Blood Pressure Reactivity in Postmenopausal Women.

Postmenopausal women (PMW) may experience endothelial dysfunction associated with arginine (ARG) deficiency relative to asymmetric dimethylarginine (ADMA) caused by oxidative stress. Endothelial dysfunction contributes to increased blood pressure (BP) responsiveness to sympathoexcitation induced by the cold pressor test (CPT). We investigated the effects of citrulline alone (CIT) and combined with the antioxidant glutathione (CIT+GSH) on vascular function. Forty-four healthy PMW were randomized to CIT (6 g), CIT+GSH (2 g + 200 mg: Setria®) or placebo (PL) for 4 weeks. Brachial artery flow-mediated dilation (FMD), aortic stiffness (pulse wave velocity, PWV), brachial and aortic BP reactivity to CPT, and serum fasting blood glucose (FBG), ARG, and ARG/ADMA ratio were measured. Baseline FBG was higher in CIT+GSH vs. PL. FMD increased after CIT+GSH vs. PL (p < 0.05). CIT and CIT+GSH increased ARG/ADMA (p < 0.05), but did not affect aortic PWV. CIT+GSH attenuated the brachial and aortic systolic BP and mean arterial pressure (MAP) responses to CPT vs. PL and CIT (p < 0.05). The improvements in FMD were related to baseline FMD (r = -0.39, p < 0.05) and aortic MAP response to CPT (r = -0.33, p < 0.05). This study showed that CIT+GSH improved FMD and attenuated systolic BP and MAP reactivity in PMW. Although CIT increased ARG/ADMA, it did not improve FMD in healthy PMW.

Editorial for the Special Issue "Benefits of Supplementation with L-arginine, Citrulline and Watermelon on Vascular and Metabolic Health".

The endothelium is crucial in controlling blood pressure and preventing cardiovascular diseases [...].

Effects of L-Citrulline Supplementation on Endothelial Function and Blood Pressure in Hypertensive Postmenopausal Women.

Aging and menopause are associated with decreased nitric oxide bioavailability due to reduced L-arginine (L-ARG) levels contributing to endothelial dysfunction (ED). ED precedes arterial stiffness and hypertension development, a major risk factor for cardiovascular disease. This study investigated the effects of L-citrulline (L-CIT) on endothelial function, aortic stiffness, and resting brachial and aortic blood pressures (BP) in hypertensive postmenopausal women. Twenty-five postmenopausal women were randomized to 4 weeks of L-CIT (10 g) or placebo (PL). Serum L-ARG, brachial artery flow-mediated dilation (FMD), aortic stiffness (carotid-femoral pulse wave velocity, cfPWV), and resting brachial and aortic BP were assessed at 0 and 4 weeks. L-CIT supplementation increased L-ARG levels (Δ13 ± 2 vs. Δ−2 ± 2 µmol/L, p < 0.01) and FMD (Δ1.4 ± 2.0% vs. Δ−0.5 ± 1.7%, p = 0.03) compared to PL. Resting aortic diastolic BP (Δ−2 ± 4 vs. Δ2 ± 5 mmHg, p = 0.01) and mean arterial pressure (Δ−2 ± 4 vs. Δ2 ± 6 mmHg, p = 0.04) were significantly decreased after 4 weeks of L-CIT compared to PL. Although not statistically significant (p = 0.07), cfPWV decreased after L-CIT supplementation by ~0.66 m/s. These findings suggest that L-CIT supplementation improves endothelial function and aortic BP via increased L-ARG availability.

Current Evidence of Watermelon (Citrullus lanatus) Ingestion on Vascular Health: A Food Science and Technology Perspective.

The amino acid L-arginine is crucial for nitric oxide (NO) synthesis, an important molecule regulating vascular tone. Considering that vascular dysfunction precedes cardiovascular disease, supplementation with precursors of NO synthesis (e.g., L-arginine) is warranted. However, supplementation of L-citrulline is recommended instead of L-arginine since most L-arginine is catabolized during its course to the endothelium. Given that L-citrulline, found mainly in watermelon, can be converted to L-arginine, watermelon supplementation seems to be effective in increasing plasma L-arginine and improving vascular function. Nonetheless, there are divergent findings when investigating the effect of watermelon supplementation on vascular function, which may be explained by the L-citrulline dose in watermelon products. In some instances, offering a sufficient amount of L-citrulline can be impaired by the greater volume (>700 mL) of watermelon needed to reach a proper dose of L-citrulline. Thus, food technology can be applied to reduce the watermelon volume and make supplementation more convenient. Therefore, this narrative review aims to discuss the current evidence showing the effects of watermelon ingestion on vascular health parameters, exploring the critical relevance of food technology for acceptable L-citrulline content in these products. Watermelon-derived L-citrulline appears as a supplementation that can improve vascular function, including arterial stiffness and blood pressure. Applying food technologies to concentrate bioactive compounds in a reduced volume is warranted so that its ingestion can be more convenient, improving the adherence of those who want to ingest watermelon products daily.

L-Citrulline supplementation attenuates aortic pulse pressure and wave reflection responses to cold stress in older adults.

BACKGROUND AND AIMS: Augmented aortic systolic blood pressure (SBP) and wave reflection via sympathetic-mediated vasoconstriction elevates the risk for adverse cardiovascular events in older adults. L-citrulline (L-CIT) supplementation has shown to reduce aortic SBP and pulse pressure (PP) responses to cold pressor test (CPT) induced sympathoactivation in young men. The aim of this study was to elucidate the efficacy of L-CIT supplementation to attenuate aortic hemodynamic responses to CPT in older adults. METHODS AND RESULTS: Sixteen older adults were randomly assigned to placebo or L-CIT (6 g/day) for 14-days in a crossover, double-blind, placebo-controlled design. Brachial SBP and aortic SBP, PP, augmented pressure (AP), augmentation index standardized at 75 bpm (AIx@75), and pressure of the forward (Pf) and reflected (Pb) waves were evaluated at rest and during CPT pre- and post-intervention. Although no hemodynamic changes at rest, brachial SBP (Δ-12 ± 18 vs. Δ4 ± 14 mmHg; P = 0.008) and aortic SBP (Δ-10 ± 14 vs. Δ4 ± 12 mmHg; P = 0.005), PP (Δ-10 ± 12 vs. Δ4 ± 11 mmHg; P = 0.002), AP (Δ-4 ± 4 vs. Δ2 ± 7 mmHg; P = 0.004), AIx@75 (Δ-3.2 ± 7.2 vs. Δ2.2 ± 6.9%; P = 0.038), Pf (Δ-6 ± 10 vs. Δ3 ± 9 mmHg; P = 0.019), and Pb (Δ-4 ± 6 vs. Δ2 ± 6 mmHg; P = 0.008) responses to the CPT were significantly attenuated following L-CIT supplementation vs. placebo. CONCLUSIONS: L-CIT supplementation attenuated aortic pulsatile pressure and pressure wave reflection responses to CPT in older adults, providing possible cardioprotection during cold-induced sympathoactivation in older adults.

Acute Citrulline Blunts Aortic Systolic Pressure during Exercise and Sympathoactivation in Hypertensive Postmenopausal Women.

PURPOSE: Hypertensive postmenopausal women (PMW) have exaggerated exercise systolic blood pressure (SBP) due to impaired functional sympatholysis. l-Citrulline (CIT) supplementation attenuates aortic SBP responses to cold pressor test (CPT)-induced vasoconstriction in young men. We hypothesized that acute CIT ingestion would attenuate aortic SBP and leg hemodynamic responses during exercise and CPT (EX + CPT). METHODS: Fifteen hypertensive PMW (61 ± 7 yr) were randomly assigned to consume either 6 g of CIT or placebo (PL) separated by a minimum 3-d washout phase. Brachial and aortic blood pressure, femoral artery blood flow (FBF), and vascular conductance (FVC) were measured at rest and during 5 min of unilateral plantarflexion exercise with a CPT applied during minutes 4 and 5. RESULTS: No differences between conditions were found in FBF, FVC, and brachial and aortic blood pressure at rest and during exercise alone. Changes in brachial SBP (CIT vs PL, 29 ± 12 vs 40 ± 10 mm Hg) and mean arterial pressure (CIT vs PL, 21 ± 10 vs 33 ± 11 mm Hg), and aortic SBP (CIT vs PL, 27 ± 11 vs 38 ± 9 mm Hg) and mean arterial pressure (CIT vs PL, 23 ± 9 vs 33 ± 11 mm Hg) to EX + CPT were lower in the CIT versus PL condition (P < 0.05). FBF, FVC, and functional sympatholysis (%ΔFVC) were not significantly different between conditions. CONCLUSIONS: Acute CIT ingestion attenuated aortic SBP response to exercise and cold-induced sympathetic activation that may prevent left ventricle overload in hypertensive PMW.

Effect of l-Arginine Supplementation on Blood Pressure in Adults: A Systematic Review and Dose-Response Meta-analysis of Randomized Clinical Trials.

A decade-old meta-analytic work indicated that l-arginine supplementation might have a blood pressure (BP)-lowering effect in different populations. However, several relevant investigations have emerged in the last 10 y, and an up-to-date systematic review and meta-analysis on this topic is currently lacking. Therefore, we aimed to examine the impact of l-arginine supplementation on BP by conducting a systematic review and dose-response meta-analysis of randomized placebo-controlled clinical trials (RCTs). We searched online databases using relevant keywords up to April 2021 to identify RCTs using oral l-arginine on systolic BP (SBP) and diastolic BP (DBP) in adults. Inclusion criteria were adult participants and an intervention duration ≥4 d. Exclusion criteria were the use of l-arginine infusion and acute interventions. A random-effects model was used to estimate the weighted mean difference (WMD) and 95% CI. Twenty-two RCTs with 30 effect sizes were included in this meta-analysis. The pooled analysis demonstrated significant decreases in SBP (WMD = -6.40 mmHg; 95% CI: -8.74, -4.05; P < 0.001) and DBP (WMD = -2.64 mmHg; 95% CI: -3.94, -1.40; P < 0.001) after l-arginine supplementation. Subgroup analysis showed significant reductions in SBP and DBP regardless of baseline BP category (normotensive, hypertensive), study duration (≤24 d, >24 d), sex (female, male), health status (healthy, unhealthy), and BMI (normal, overweight, obese). No significant changes were observed with dosages >9 g/d, trial duration >24 d, or in obese individuals. l-Arginine supplementation also appears to decrease DBP more effectively in females than in males. Moreover, meta-regression analysis for DBP demonstrated a significant relation between the dose of l-arginine intake and changes in DBP (P = 0.020). In the nonlinear dose-response analysis, the effective dosage of l-arginine supplementation was detected to be ≥4 g/d for SBP (P = 0.034), independent of trial duration. Overall, l-arginine supplementation may be effective for decreasing BP. This study was registered at PROSPERO as CRD42021242772.

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

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.

Effects of strawberries on bone biomarkers in pre- and stage 1-hypertensive postmenopausal women: a secondary analysis.

Postmenopausal women experience an increase in bone remodeling with the rate of bone resorption superseding the rate of bone formation. This results in a net bone loss with a subsequent increased risk for osteoporosis and fractures. High blood pressure (BP) has been associated with loss of bone mineral density and increased propensity to fractures. Strawberries are rich in polyphenols, which have been shown to have anti-hypertensive and bone-protective properties. Thus, we examined whether daily intake of strawberries would positively affect biomarkers of bone metabolism in postmenopausal women with pre- and stage 1-hypertension. Participants (age: 59 ± 6 years; body mass index: 31.5 ± 4.1 kg m-2; systolic BP: 140 ± 13 mmHg) were randomly assigned to consume (1) 50 g of freeze-dried strawberry powder (FDSP), (2) 25 g FDSP + 25 g of placebo powder, or (3) 50 g placebo powder for eight weeks. Results indicate a significant time-by-treatment interaction (P = 0.04) for serum insulin-like growth factor (IGF)-1, a hormone that plays a major role in bone formation. Serum concentrations of bone-specific alkaline phosphatase, a marker of bone formation, and tartrate-resistant acid phosphatase-5b, a specific marker of bone resorption, were not affected by FDSP compared to placebo. Although not statistically significant, after eight weeks, osteocalcin increased in the 50 g FDSP group with a large effect size (d = 0.6) when compared to the placebo-control group. Adiponectin increased by 5% and 6% in the 25 g and 50 g FDSP groups, respectively, while it declined in the placebo-control group by 25% (P = 0.03 for time-by-treatment interaction). Our findings suggest that consumption of 25 g FDSP increases IGF-1 in postmenopausal women with pre- and stage 1-hypertension. However, further studies are needed to assert the effectiveness of a strawberry intervention for bone health.

Effects of L-Citrulline Supplementation and Aerobic Training on Vascular Function in Individuals with Obesity across the Lifespan.

Children with obesity are at higher risk for developing cardiometabolic diseases that once were considered health conditions of adults. Obesity is commonly associated with cardiometabolic risk factors such as dyslipidemia, hyperglycemia, hyperinsulinemia and hypertension that contribute to the development of endothelial dysfunction. Endothelial dysfunction, characterized by reduced nitric oxide (NO) production, precedes vascular abnormalities including atherosclerosis and arterial stiffness. Thus, early detection and treatment of cardiometabolic risk factors are necessary to prevent deleterious vascular consequences of obesity at an early age. Non-pharmacological interventions including L-Citrulline (L-Cit) supplementation and aerobic training stimulate endothelial NO mediated vasodilation, leading to improvements in organ perfusion, blood pressure, arterial stiffness, atherosclerosis and metabolic health (glucose control and lipid profile). Few studies suggest that the combination of L-Cit supplementation and exercise training can be an effective strategy to counteract the adverse effects of obesity on vascular function in older adults. Therefore, this review examined the efficacy of L-Cit supplementation and aerobic training interventions on vascular and metabolic parameters in obese individuals.

L-Citrulline Supports Vascular and Muscular Benefits of Exercise Training in Older Adults.

Age-associated reduction in endothelial nitric oxide (NO) synthesis contributes to the development of cardiovascular diseases and sarcopenia. L-Citrulline is a precursor of NO with the ability to improve vascular function and muscle protein synthesis. We hypothesize that vascular and muscular benefits associated with oral L-citrulline supplementation might be augmented by concomitant supplementation with exercise training in older adults.

Effects of Montmorency Tart Cherry Juice Consumption on Cardiometabolic Biomarkers in Adults with Metabolic Syndrome: A Randomized Controlled Pilot Trial.

Greater than one-third of adults in the United States have metabolic syndrome (MetS), a cluster of risk factors highly associated with the development of cardiovascular diseases. Premature vascular dysfunction in MetS may lead to accelerated age-related atherogenesis and arterial stiffening, thereby increasing cardiovascular risk. Montmorency tart cherries (Prunus cerasus L.) are rich in bioactive compounds, such as anthocyanins, known to exert cardiovascular protective effects. Previous research suggests that tart cherry juice consumption may improve cardiovascular health. The objective of this study was to evaluate the effects of daily consumption of tart cherry juice on hemodynamics, arterial stiffness, and blood biomarkers of cardiovascular and metabolic health in men and women with MetS. In a randomized, single-blind, placebo-controlled, parallel-arm pilot clinical trial, 19 men and women 20 to 60 years of age with MetS consumed 240 mL of tart cherry juice (Tart Cherry; n = 5 males, 4 females) or an isocaloric placebo-control drink (Control; n = 5 males, 5 females) twice daily for 12 weeks. Arterial stiffness (pulse wave velocity), brachial and aortic blood pressures, wave reflection (augmentation index), and blood biomarkers of cardiovascular and metabolic health were assessed at baseline and 6 and 12 weeks. Oxidized low-density lipoprotein and soluble vascular cell adhesion molecule-1 were significantly lower (P = .047 and P = .036, respectively) in Tart Cherry than Control at 12 weeks, but were not significantly lower than baseline values. There was a trend for total cholesterol to be lower (P = .08) in Tart Cherry than Control at 12 weeks. No significant changes were observed in hemodynamics, arterial stiffness, or other blood biomarkers assessed. These results suggest that daily tart cherry consumption may attenuate processes involved in accelerated atherogenesis without affecting hemodynamics or arterial stiffness parameters in this population. The pilot nature of this study warrants interpreting these findings with caution, and future clinical trials with a larger sample size are needed to confirm these findings.

The effects of pumpkin seed oil supplementation on arterial hemodynamics, stiffness and cardiac autonomic function in postmenopausal women.

BACKGROUND: Postmenopausal women have a higher prevalence of hypertension than age-match men. Evidence from animal studies have demonstrated the antihypertensive effects of pumpkin seed oil (PSO). We examined the effects of PSO supplementation on vascular function and heart rate variability (HRV) in postmenopausal women with elevated blood pressure (BP). MATERIALS AND METHODS: Participants were randomly assigned to either a PSO (n = 12) or a placebo group (n = 11). Participants in the PSO group consumed 3 g/day of PSO. Brachial and central BP, wave reflection (augmentation index, AIx), arterial stiffness (SI) and various HRV parameters were measured before and after 6 weeks. RESULTS: AIx, brachial and central systolic BP significantly (P < 0.05) decreased following PSO but not after placebo. SI and HRV parameters remained unchanged after PSO or placebo. CONCLUSION: PSO improved arterial hemodynamics in postmenopausal women and therefore might be effective in the prevention and treatment of hypertension in this population. CLINICAL TRIAL ID: (NCT03716960).

Watermelon and l-arginine consumption improve serum lipid profile and reduce inflammation and oxidative stress by altering gene expression in rats fed an atherogenic diet.

Watermelon (Citrullus lanatus) is rich in l-citrulline, an l-arginine precursor that may reduce cardiovascular disease risk. The purpose of this study was to compare the effects of watermelon powder and l-arginine on lipid profiles, antioxidant capacity, and inflammation in rats fed an atherogenic diet. We hypothesized that watermelon and l-arginine would increase antioxidant capacity and reduce blood lipids and inflammation by modulating hepatic gene expression. Male Sprague-Dawley rats aged 21 days (N = 32) were assigned to 3 groups and fed diets containing watermelon powder (0.5% wt/wt), l-arginine (0.3% as 0.36% l-arginine HCl wt/wt), or a control diet for 9 weeks. Watermelon and l-arginine supplementation improved lipid profiles by lowering serum concentrations of triglycerides, total cholesterol, and low-density lipoprotein cholesterol (P < .050). Serum concentrations of C-reactive protein were significantly lower (P < .050) in the watermelon and l-arginine groups. Rats in the watermelon and l-arginine groups showed reduced oxidative stress, increased total antioxidant capacity, and higher concentrations of superoxide dismutase and glutathione S-transferase (P < .050). Concentrations of aspartate aminotransferase, alkaline phosphatase, and lactate dehydrogenase were lower (P < .050) in the watermelon and l-arginine groups. Watermelon and l-arginine consumption upregulated hepatic gene expression of endothelial nitric oxide synthase and downregulated expression of fatty acid synthase, 3-hydroxy-3-methylglutaryl-CoA reductase, sterol regulatory element-binding protein 1, sterol regulatory element-binding protein 2, cyclooxygenase-2, and nuclear factor-κB p65 (P < .050). The results support the hypothesis that watermelon and arginine improve cardiovascular disease risk factors including lipid profile, antioxidant capacity, and inflammation by altering relevant gene expression.

Effects of Watermelon Powder and l-arginine Supplementation on Azoxymethane-Induced Colon Carcinogenesis in Rats.

Diets high in fruits and vegetables may help prevent colorectal cancer (CRC). Watermelon consumption may reduce CRC risk due to its concentration of l-citrulline and its role in endothelial nitric oxide (NO) production. Research suggests that increased NO levels have tumoricidal effects. The purpose of this study was to determine the effects of watermelon powder supplementation on aberrant crypt foci (ACF) formation, precancerous lesions, and expression of genes associated with colon carcinogenesis. Thirty-two male Sprague-Dawley rats were assigned into three groups: control, 0.36% l-arginine, or 0.5% watermelon powder and injected with azoxymethane (15 mg/kg body weight). Both l-arginine and watermelon powder groups exhibited lower total numbers of ACF and high multiplicity ACF (P < 0.01). The watermelon powder group exhibited higher NO levels and lower 8-hydroxyguanosine DNA damage (P < 0.05). Watermelon powder and l-arginine downregulated 8-oxoguanine DNA glycosylase gene expression and upregulated O6-methylguanine DNA methyltransferase gene expression (P < 0.05). Cyclooxgenase-2 gene expression was lower for rats fed with watermelon powder (P < 0.05). These results suggest that watermelon powder or l-arginine supplementation may reduce the risk of colon cancer by suppressing ACF formation through lowering oxidative DNA damage and inflammation, modulating DNA repair enzyme expression, and/or enhancing NO production.

Effectiveness of Tai Chi on Cardiac Autonomic Function and Symptomatology in Women With Fibromyalgia: A Randomized Controlled Trial.

The present study examined the effects of a 12-week Tai Chi (TC) training regimen on heart rate variability (HRV), symptomatology, muscle fitness and body composition in women with fibromyalgia. Participants were randomly assigned to either a TC training group (n = 18) or a control group (n = 19). HRV, symptomatology, muscle fitness and body composition were measured before and after 12 weeks. There were significant decreases (p < 0.05) in sympathovagal balance (LnLF/LnHF), sympathetic tone (LnLF, nLF), pain, and fatigue, and significant increases (p < 0.05) in parasympathetic tone (LnHF, nHF), strength and flexibility following TC compared with no changes after control. The changes in LnLF and LnLF/LnHF were correlated with changes in pain. There were no significant changes in HR, sleep quality and body composition after TC or control. TC may be an effective therapeutic intervention for improving sympathovagal balance, pain, fatigue, strength and flexibility in women with fibromyalgia.

The Effects of Stretching Training on Cardiac Autonomic Function in Obese Postmenopausal Women.

Context • Menopause and obesity are associated with autonomic dysfunction. Unconventional exercise modalities that include an important flexibility component seem to improve cardiac autonomic function by lowering sympathetic tone and increasing vagal modulation of the heart rate (HR). Yet clear evidence of the effects of stretching training (ST) on cardiac autonomic modulation is limited. Objective • The present study intended to examine the effects of ST on HR variability (HRV) and flexibility in obese postmenopausal women. Design • The research team designed a randomized, controlled trial. Setting • The study was conducted at the Florida State University (Tallahassee, FL, USA). Participants • Twenty-four obese, postmenopausal women, aged 50-65 y with a body mass index of >30 but <40 kg/m2 participated in the study. Intervention • Participants were randomly assigned either to an ST group (n = 12) or a no-exercise control group (n = 12). The study was 8 wk in duration. Outcome Measures • Participant HRV and sit-and-reach scores (SRSs) were measured at baseline and after 8 wk of training. Results • Significant decreases occurred for the ST group between baseline and postintervention in sympathetic activity, as measured by normalized low frequency (nLF) power, and in sympathovagal balance, as measured by the ratio of the natural logarithm low frequency (LnLF) activity to the natural logarithm high frequency (LnHF) power, with P < .01 for both measures. The decreases for the ST group were significantly greater than those for the control group for the nLF and LnLF/LnHF, with P < .05 for both measures. Significant increases in vagal tone occurred for the ST group between baseline and postintervention, as measured by the normalized high frequency (nHF) power, with P < .01, and in SRS following ST, with P < .001. The increases for the ST group were significantly greater than those for the control group for the nHF and SRS, with P < .05 for both measures. The changes in SRS were correlated with the changes in the LnLF/LnHF power, with r = .65 and P < .03 negatively correlated. Conclusions • The findings indicated that ST can improve cardiac autonomic modulation by increasing vagal tone and decreasing sympathetic activity in obese postmenopausal women. The improvement in SRS partially explained the decrease in the sympathovagal balance. Because older or obese individuals have a higher risk of developing cardiovascular diseases, they could potentially benefit from ST.

Influence of L-citrulline and watermelon supplementation on vascular function and exercise performance.

PURPOSE OF REVIEW: L-Citrulline, either synthetic or in watermelon, may improve vascular function through increased L-arginine bioavailability and nitric oxide synthesis. This article analyses potential vascular benefits of L-citrulline and watermelon supplementation at rest and during exercise. RECENT FINDINGS: There is clear evidence that acute L-citrulline ingestion increases plasma L-arginine, the substrate for endothelial nitric oxide synthesis. However, the subsequent acute improvement in nitric oxide production and mediated vasodilation is inconsistent, which likely explains the inability of acute L-citrulline or watermelon to improve exercise tolerance. Recent studies have shown that chronic L-citrulline supplementation increases nitric oxide synthesis, decreases blood pressure, and may increase peripheral blood flow. These changes are paralleled by improvements in skeletal muscle oxygenation and performance during endurance exercise. The antihypertensive effect of L-citrulline/watermelon supplementation is evident in adults with prehypertension or hypertension, but not in normotensives. However, L-citrulline supplementation may attenuate the blood pressure response to exercise in normotensive men. SUMMARY: The beneficial vascular effects of L-citrulline/watermelon supplementation may stem from improvements in the L-arginine/nitric oxide pathway. Reductions in resting blood pressure with L-citrulline/watermelon supplementation may have major implications for individuals with prehypertension and hypertension. L-Citrulline supplementation, but not acute ingestion, have shown to improve exercise performance in young healthy adults.

Whole-Body Vibration Exercise Therapy Improves Cardiac Autonomic Function and Blood Pressure in Obese Pre- and Stage 1 Hypertensive Postmenopausal Women.

OBJECTIVE: Whole-body vibration (WBV) is an unconventional exercise therapy that appears to provide the same benefits of resistance training in postmenopausal women while being more safe and gentle on the joints. This study evaluated the effect of an 8-week WBV exercise regimen on heart rate variability (HRV) and blood pressure (BP) in obese postmenopausal women. DESIGN: Randomized controlled study with two parallel groups. PARTICIPANTS: Twenty-five (age 50-65 years) obese (body-mass index >30 and <40 kg/m2) postmenopausal women. INTERVENTION: Participants were randomly assigned to a WBV training group or nonexercising control group. Participants in the WBV group completed the supervised training 3 times a week. WBV training consisted of four static and four dynamic leg exercises (normal, high, and wide-stance squats and calf-raises) with vertical vibration (25-40 Hz and low-high amplitude) progressed throughout the 8 weeks. OUTCOME MEASURES: Brachial systolic BP (SBP) and diastolic BP (DBP) and HRV: sympathovagal balance (natural logarithm of low frequency [LnLF]/natural logarithm of high frequency [LnHF]; normalized low frequency [nLF]/normalized high frequency [nHF]), parasympathetic tone (LnHF, nHF, natural logarithm of root mean square of successive differences [LnRMSSD]), sympathetic tone (LnLF, nLF), natural logarithm of total power, and heart rate (HR). RESULTS: There were significant group × time interactions (p < 0.05) for brachial SBP, DBP, LnLF/LnHF, and nLF/nHF that significantly decreased (p < 0.01) after WBV, compared with no changes after control. There was a significant (p < 0.05) increase in nHF and decrease in nLF in the WBV group compared with baseline, yet the changes were not different than those in the control group. No significant changes were observed in LnTP, LnLF, LnHF, LnRMSSD, or HR after 8 weeks in either group. CONCLUSIONS: WBV training for 8 weeks is an adequate unconventional exercise intervention for improving sympathovagal balance and BP in previously sedentary obese postmenopausal women.