The Effects of a Multiflavonoid Supplement on Vascular and Hemodynamic Parameters following Acute Exercise

Antioxidants can decrease oxidative stress and combined with acute exercise they may lead to further decreases in blood pressure. The purpose of this study was to investigate the effects of 2 weeks of antioxidant supplementation on vascular distensibility and cardiovascular hemodynamics during postexercise hypotension. Methods. Twenty young subjects were randomized to placebo (n = 10) or antioxidant supplementation (n = 10) for two weeks. Antioxidant status, vascular distensibility, and hemodynamics were obtained before, immediately, and 30 minutes after an acute bout of aerobic exercise both before and after supplementation. Results. Two weeks of antioxidant supplementation resulted in a greater systolic blood pressure (SBP) decrease during postexercise hypotension (PEH) and significant decreases in augmentation index versus placebo (12.5% versus 3.5%, resp.). Also ferric-reducing ability of plasma (FRAP) increased significantly (interaction P = 0.024) after supplementation. Conclusion. Supplementation showed an additive effect on PEH associated with increased FRAP values and decreases in systolic blood pressure and augmentation index

Differential Post-Exercise Blood Pressure Responses between Blacks and Caucasians

Post-exercise hypotension (PEH) is widely observed in Caucasians (CA) and is associated with histamine receptors 1- and 2- (H1R and H2R) mediated post-exercise vasodilation. However, it appears that blacks (BL) may not exhibit PEH following aerobic exercise. Hence, this study sought to determine the extent to which BL develop PEH, and the contri- bution of histamine receptors to PEH (or lack thereof) in this population. Forty-nine (22 BL, 27 CA) young and healthy subjects completed the study. Subjects were randomly assigned to take either a combined H1R and H2R antagonist (fexofenadine and ranitidine) or a con- trol placebo. Supine blood pressure (BP), cardiac output and peripheral vascular resistance measurements were obtained at baseline, as well as at 30 min, 60 min and 90 min after 45 min of treadmill exercise at 70% heart rate reserve. Exercise increased diastolic BP in young BL but not in CA. Post-exercise diastolic BP was also elevated in BL after exercise with histamine receptor blockade. Moreover, H1R and H2R blockade elicited differential responses in stroke volume between BL and CA at rest, and the difference remained follow- ing exercise. Our findings show differential BP responses following exercise in BL and CA, and a potential role of histamine receptors in mediating basal and post-exercise stroke vol- ume in BL. The heightened BP and vascular responses to exercise stimulus is consistent with the greater CVD risk in BL

Sex differences in autonomic function following maximal exercise

Background: Heart rate variability (HRV), blood pressure variability, (BPV) and heart rate recovery (HRR) are measures that provide insight regarding autonomic function. Maximal exercise can affect autonomic function, and it is unknown if there are sex differences in autonomic recovery following exercise. Therefore, the purpose of this study was to determine sex differences in several measures of autonomic function and the response following maximal exercise. Methods: Seventy-one (31 males and 40 females) healthy, nonsmoking, sedentary normotensive subjects between the ages of 18 and 35 underwent measurements of HRV and BPV at rest and following a maximal exercise bout. HRR was measured at minute one and two following maximal exercise. Results: Males have significantly greater HRR following maximal exercise at both minute one and two; however, the significance between sexes was eliminated when controlling for VO2 peak. Males had significantly higher resting BPV-low-frequency (LF) values compared to females and did not significantly change following exercise, whereas females had significantly increased BPV-LF values following acute maximal exercise. Although males and females exhibited a significant decrease in both HRV-LF and HRV-high frequency (HF) with exercise, females had significantly higher HRV-HF values following exercise. Males had a significantly higher HRV-LF/HF ratio at rest; however, both males and females significantly increased their HRV-LF/HF ratio following exercise. Conclusions: Pre-menopausal females exhibit a cardioprotective autonomic profile compared to age-matched males due to lower resting sympathetic activity and faster vagal reactivation following maximal exercise. Acute maximal exercise is a sufficient autonomic stressor to demonstrate sex differences in the critical post-exercise recovery period

Racial and Aging Effects of Acute Antioxidant Supplementation

BACKGROUND: African Americans (AA) have a significantly higher risk of cardiovascular disease (CVD) compared to Caucasians (CA). This could be due to the elevated oxidative stress (OS) seen in AA. There are also significant sex differences in CVD, with post-menopausal females surpassing males in CVD risk factors, potentially due to the loss of estrogen, which has antioxidant properties. In addition, aging leads to elevated OS and vascular dysfunction. Acute antioxidant supplementation (AOX) has been shown to reduce free radicals and improve vascular function. METHODS: We investigated the effects of AOX on endothelial function, arterial stiffness, exercise blood flow, central and peripheral blood pressures and oxidative stress biomarkers in AA versus CA, and in males versus females, and if this relationship changes differently with aging. Applanation tonometry and ultrasonography were used to measure pressures, arterial stiffness values and blood flow during handgrip exercise. Endothelial function was assessed using strain gauge plethysmography and flow-mediated dilation, and oxidative stress biomarkers were assessed by measuring levels of superoxide dismutase, protein carbonyls and thiobarbituric acid reactive substances. RESULTS: In young adults, there are racial differences in resistance vessel response to reactive hyperemia following AOX, with no effect of race on macrovascular function (FMD%) following AOX. Older CA adults improved resistance vessel function with AOX whereas AA reduced resistance vessel response with AOX. FMD% improves following AOX in both CA and AA, with a greater improvement in AA. There was a significant effect of race, exercise and AOX on forearm vascular conductance (FVC) response with exercise in the older group. Young females displayed significantly higher FMD% but males improved FMD% with AOX. In older adults, although both sexes improved with AOX, females improved significantly more. Microvascular function was consistently higher in males compared to females. FMD% appears to be the most affected by sex and antioxidant supplementation, especially in older females. CONCLUSIONS: Our data indicate that AOX affects macrovascular function and microvascular function differently, and this is impacted by age, race and sex

Autonomic Recovery Is Delayed in Chinese Compared with Caucasian following Treadmill Exercise.

UNLABELLED:Caucasian populations have a higher prevalence of cardiovascular disease (CVD) when compared with their Chinese counterparts and CVD is associated with autonomic function. It is unknown whether autonomic function during exercise recovery differs between Caucasians and Chinese. The present study investigated autonomic recovery following an acute bout of treadmill exercise in healthy Caucasians and Chinese. Sixty-two participants (30 Caucasian and 32 Chinese, 50% male) performed an acute bout of treadmill exercise at 70% of heart rate reserve. Heart rate variability (HRV) and baroreflex sensitivity (BRS) were obtained during 5-min epochs at pre-exercise, 30-min, and 60-min post-exercise. HRV was assessed using frequency [natural logarithm of high (LnHF) and low frequency (LnLF) powers, normalized high (nHF) and low frequency (nLF) powers, and LF/HF ratio] and time domains [Root mean square of successive differences (RMSSD), natural logarithm of RMSSD (LnRMSSD) and R-R interval (RRI)]. Spontaneous BRS included both up-up and down-down sequences. At pre-exercise, no group differences were observed for any HR, HRV and BRS parameters. During exercise recovery, significant race-by-time interactions were observed for LnHF, nHF, nLF, LF/HF, LnRMSSD, RRI, HR, and BRS (up-up). The declines in LnHF, nHF, RMSSD, RRI and BRS (up-up) and the increases in LF/HF, nLF and HR were blunted in Chinese when compared to Caucasians from pre-exercise to 30-min to 60-min post-exercise. Chinese exhibited delayed autonomic recovery following an acute bout of treadmill exercise. This delayed autonomic recovery may result from greater sympathetic dominance and extended vagal withdrawal in Chinese. TRIAL REGISTRATION:Chinese Clinical Trial Register ChiCTR-IPR-15006684

CONSORT Flow diagram.

<p>CONSORT Flow diagram.</p

Change value from baseline for (a) LnHF, natural logarithm of high frequency (b) nHF, normalized high frequency (c) nLF, normalized low frequency (d) LF/HF, LF/ HF ratio (e) LnRMSSD, natural logarithm of RMSSD (f) HR, heart rate (g) BRS(up-up), Baroreflex sensitivity up-up, at 30-min and 60-min after exercise.

<p>Data are reported as mean ± SE (#significant race-by-time interaction; *significant change compared with baseline).</p

Baroreflex sensitivity (BRS) determined by the sequence method, pre and 30-min and 60-min post exercise in Caucasian and Chinese individuals.

<p>(a) BRS(up-up) showed a significant race by time interaction. *P<0.05 (b) There was no race-by-time interaction for the change in BRS(dn-dn).</p

Exercise hemodynamic and water intake.

<p>Exercise hemodynamic and water intake.</p