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

Protective effects of acute moderate exercise on vaccination induced inflammation, arterial function and vaccine efficacy

Acute induced inflammation, using vaccination, reduces flow-mediated vasodilation in the conduit artery in young healthy volunteers. However, this has not been shown in older adults. Immunosenescence with advancing age results in inadequate protection from disease because of ineffective responses to vaccination. An acute bout of moderate aerobic exercise improves arterial and endothelial function and may increase the efficacy of the vaccine in young individuals. Hence, this study sought to evaluate the effect of acute systemic inflammation on endothelial function and wave reflection in older adults. The second aim was to evaluate if acute moderate intensity endurance exercise immediately prior to induced inflammation can prevent the negative effect of acute systemic inflammation on vascular function while augmenting the efficacy of the vaccine. Fifty-nine healthy volunteers between 55 – 75 years of age were randomly allocated to an exercise or control group. Arterial function and inflammatory markers were measured at baseline, 24 hours and 48 hours after influenza vaccine and sham injections. Antibody titers were measured at baseline and 4 weeks following the Influenza vaccine. CRP increased when measured at 24 and 48 hours and IL-6 increased at 24 hours from baseline after the Influenza vaccine compared to the sham injection while unexpectedly, arterial function was unaltered. There were no significant correlations between changes in inflammatory markers and changes in arterial function. Fitness was related to endothelial function as baseline. Endothelial function was significantly higher in individuals classified as having good fitness compared to the poor fitness category. There was a significant decrease in the endothelial function at 48 hours after vaccination compared to baseline in the fair fitness while there was significant decrease in the endothelial function when measured at 24 and 48 hours as compared to the baseline in good fitness category group. The endothelial function was unaffected in the poor fitness group. There were no differences in the levels of antibody titers against the H3N2 influenza strain between the men and women in exercise group as compared to the control group. However, women in the exercise group had a significantly higher antibody response for H1N1 influenza strain. In conclusion, there was dissociation between inflammation and endothelial function following induced acute systemic inflammation in older adults. The responses of endothelial function to induced acute systemic inflammation were related to fitness. Acute moderate aerobic exercise was not immune-stimulatory in healthy older men, but may serve as a vaccine adjuvant in older women

Acute inflammation elicits decreased blood pressure but similar arterial stiffness in young African American adults

Abstract African Americans (AA) have a higher risk for cardiovascular disease (CVD) as compared to their White (W) counterparts. CVD is characterized by increased blood pressure (BP), arterial stiffness and systemic inflammation. An acute inflammatory stimulus may explain physiological manifestations responsible for amplified CVD in AA that are not apparent at rest. The purpose of this study was to evaluate central and peripheral BP, central and local arterial stiffness, and indices of pulse wave morphology in young healthy AA and W participants in response to acute inflammation. Concentrations of the inflammatory cytokine interleukin‐6 (IL‐6) and measures of central and peripheral BP, central arterial stiffness (carotid–femoral pulse wave velocity (cfPWV)), local carotid arterial stiffness (β‐stiffness, elastic modulus (Ep)), and indices of pulse wave morphology were assessed in 28 participants (21 ± 2 years, AA: n = 11) at baseline (BL), 24 h and 48 h post‐inflammation. Changes in IL‐6 concentrations (ΔIL‐6) were significantly greater at 24 h as compared to 48 h post‐inflammation (0.652 ± 0.644 vs. −0.146 ± 0.532 pg/μl, P ≤ 0.0001). Among AA participants, central and peripheral diastolic BP were significantly decreased at 24 h post‐inflammation as compared to BL (aortic diastolic BP: −4 ± 4 mmHg, P = 0.016; brachial diastolic BP: −4 ± 4 mmHg, P = 0.014). AA participants also experienced a significant decrease in central and peripheral mean arterial BP at 48 h post‐inflammation as compared to BL (aortic mean arterial pressure: −4 ± 4 mmHg, P = 0.009; brachial mean arterial pressure: −4 ± 4 mmHg, P = 0.012). Despite haemodynamic changes, there were no differences in central or local carotid arterial stiffness or indices of pulse wave morphology

Arterial stiffness and blood pressure are similar in naturally menstruating and oral contraceptive pill-using women during the higher hormone phases

New Findings What is the central question of this study? Are there differences in blood pressure, arterial stiffness and indices of pressure waveforms between young oral contraceptive pill-using and naturally menstruating women during lower and higher hormone phases of their cycles? What is the main finding and its importance? Blood pressure, arterial stiffness and indices of pressure waveforms are influenced similarly by exogenous and endogenous hormones. However, lower levels of exogenous hormones moderately increase blood pressure among oral contraceptive pill-using women. Elevations in blood pressure (BP) are understood as having a bidirectional relationship with stiffening of central and peripheral arteries. Arterial stiffness is mitigated by oestrogen, which aides in arterial vasorelaxation. To evaluate whether BP, stiffness, and pressure waveforms were different between young healthy naturally menstruating (non-OCP) and oral contraceptive pill (OCP)-using women, we measured brachial and aortic BPs, carotid-to-femoral pulse wave velocity, carotid β-stiffness, elastic modulus, central augmentation index and augmentation index normalized to a heart rate of 75 bpm, and forward and backward pressure waveforms in 22 women (22 (1) years, OCP: n = 12). To assess phasic differences, women were studied during the early follicular (≤5 days of menstruation onset) and early luteal (4 (2) days post-ovulation) phases of non-OCP and compared to the placebo pill (≤5 days of onset) and active pill (≤5 days of highest-dose active pill) phases of OCP. During the lower hormone phases, OCP users had significantly higher brachial systolic blood pressure (SBP) (119.3 (8.3) vs. 110.2 (8.3) mmHg, P = 0.02) and aortic SBP (104.10 (7.44) vs. 96.80 (6.39) mmHg, P = 0.03) as compared to non-OCP users; however, during the higher hormone phases, there were no differences in measures of brachial or aortic BP, arterial stiffness, or indices of BP waveforms between OCP and non-OCP users (P ≥ 0.05). In conclusion, exogenous and endogenous hormones have similar influences on BP and arterial stiffness; however, lower levels of exogenous hormones augment both central and peripheral BPs.https://doi.org/10.1113/EP09015