Hemodynamic and arterial stiffness differences between African-Americans and Caucasians after maximal exercise

Nocturnal Hemodynamics in Somali Americans: Implications for Cardiovascular Risk

INTRODUCTION

Cardiovascular health disparities are present within several minority communities, but it is unclear if such disparities are present in a growing African American subpopulation, Somali Americans, who differ genetically and culturally from African Americans of Western African ancestry. Ambulatory blood pressure (BP) monitoring remains a gold standard measure to examine 24-h BP patterns to stratify cardiovascular risk profile. We sought to examine differences in the 24-h BP profile in a sample of young Somali Americans and compare their BP patterns to White study participants. We hypothesized that their BP and heart rate (HR) would be higher compared to closely matched White participants.

METHODS

We recruited 50 participants (25 Somali) in whom BP recordings were obtained every 20 min throughout the entire 24-h monitoring period to quantify BP, HR, and ambulatory arterial stiffness. Daytime BP/HR was quantified between 10:00 a.m. and 8:00 p.m., and nighttime BP/HR was assessed between 12:00 a.m. and 6:00 a.m.

RESULTS

Daytime BP and HR were similar between racial groups (p > 0.05). Nighttime BP was similar between groups (p > 0.05), but Somali American individuals exhibited a higher nocturnal HR compared to White participants (p = 0.013). Nocturnal dipping in diastolic BP and HR dipping was attenuated in Somali Americans compared to White adults (p = 0.038, 0.007). Somali participants also had higher ambulatory arterial stiffness (p = 0.045).

CONCLUSION

Twenty four-hour hemodynamics, specifically ambulatory arterial stiffness, nocturnal BP, and nocturnal HR, differ in young Somali Americans compared to White adults. These findings provide new insight into potential cardiovascular health disparities and future cardiovascular risk within the burgeoning Somali American community.

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

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.

Racial Differences in Blood Pressure and Autonomic Recovery Following Acute Supramaximal Exercise in Women

Despite the growing popularity of high-intensity anaerobic exercise, little is known about the acute effects of this form of exercise on cardiovascular hemodynamics or autonomic modulation, which might provide insight into the individual assessment of responses to training load. The purpose of this study was to compare blood pressure and autonomic recovery following repeated bouts of acute supramaximal exercise in Black and White women. A convenience sample of twelve White and eight Black young, healthy women were recruited for this study and completed two consecutive bouts of supramaximal exercise on the cycle ergometer with 30 min of recovery in between. Brachial and central aortic blood pressures were assessed by tonometry (SphygmoCor Xcel) at rest and 15-min and 30-min following each exercise bout. Central aortic blood pressure was estimated using brachial pressure waveforms and customized software. Autonomic modulation was measured in a subset of ten participants by heart-rate variability and baroreflex sensitivity. Brachial mean arterial pressure and diastolic blood pressure were significantly higher in Blacks compared to Whites across time (race effect, p = 0.043 and p = 0.049, respectively). Very-low-frequency and low-frequency bands of heart rate variability, which are associated with sympathovagal balance and vasomotor tone, were 22.5% and 24.9% lower, respectively, in Blacks compared to Whites (race effect, p = 0.045 and p = 0.006, respectively). In conclusion, the preliminary findings of racial differences in blood pressure and autonomic recovery following supramaximal exercise warrant further investigations of tailored exercise prescriptions for Blacks and Whites.

Arterial Stiffness Response to Acute Combined Training with Different Volumes in Coronary Artery Disease and Heart Failure Patients

Resistance training has been shown to acutely increase arterial stiffness (AS), while endurance training appears to decrease AS. However, the findings are from studies in apparently healthy subjects and have limited applicability to patients at low and high cardiovascular risk, for whom combined exercise is recommended. We compared the time course of changes in local and regional indices of AS in response to high-volume combined endurance training (CET) and high-volume combined resistance training (CRT) in patients with coronary artery disease (CAD) and heart failure (HF). We studied 20 men with CAD and HF (10 each) aged 68.3 ± 9.6 years. AS was measured by pulse wave velocity (PWV), and brachial and central blood pressure (BP) were determined after 15 min of rest and 5 and 15 min after the exercise session. All patients completed two sessions on nonconsecutive days. A protocol by time interaction effect was observed for carotid (η² = 0.21, p = 0.02), aortic (η² = 0.60, p < 0.001), and femoral (η² = 0.46, p = 0.01) PWV after CET and CRT, suggesting that PWV decreased after CET and increased after CRT. Decreases in the brachial and central variables of BP across time points were observed in both protocols. CET decreased whereas CRT increased carotid, aortic, and femoral PWV at 15 min after exercise in patients with CAD and HF.

Low Vitamin D Status Relates to the Poor Response of Peripheral Pulse Wave Velocity Following Acute Maximal Exercise in Healthy Young Men

The primary objective of this study was to determine the effects of vitamin D levels on peripheral pulse wave velocity (pPWV) following acute maximal exercise in healthy young adults. Fifty male healthy adults from National Chung Cheng University participated in the study. Participants were divided into the 25-hydroxyvitamin D (25(OH)D) sufficiency group (n = 28, 25(OH)D ≥ 50 nmol/L) and deficiency group (n = 22, 25(OH)D < 50 nmol/L). The acute maximal exercise was performed using an incremental cycling test to exhaustion. Additionally, the pPWV and blood pressure were obtained at rest and 0, 15, 30, 45, 60 min after acute maximal exercise. The results show that 25(OH)D deficiency group had higher pPWV at post-exercise (5.34 ± 0.71 vs. 4.79 ± 0.81 m/s, p < 0.05), post-exercise 15 min (5.13 ± 0.53 vs. 4.48 ± 0.66 m/s, p < 0.05) and post-exercise 30 min (5.26 ± 0.84 vs. 4.78 ± 0.50 m/s, p < 0.05) than the sufficiency group. Furthermore, there was a significant inverse correlation between 25(OH)D levels and pPWV following acute maximal exercise. Our study demonstrated that low vitamin D status relates to the poor response of pPWV following maximal exercise in healthy young men. Vitamin D deficiency may increase the risk of incident cardiovascular events after acute exhaustive exercise, even in healthy and active adults.

Aortic haemodynamics: the effects of habitual endurance exercise, age and muscle sympathetic vasomotor outflow in healthy men

PURPOSE

We determined the effect of habitual endurance exercise and age on aortic pulse wave velocity (aPWV), augmentation pressure (AP) and systolic blood pressure (aSBP), with statistical adjustments of aPWV and AP for heart rate and aortic mean arterial pressure, when appropriate. Furthermore, we assessed whether muscle sympathetic nerve activity (MSNA) correlates with AP in young and middle-aged men.

METHODS

Aortic PWV, AP, aortic blood pressure (applanation tonometry; SphygmoCor) and MSNA (peroneal microneurography) were recorded in 46 normotensive men who were either young or middle-aged and endurance-trained runners or recreationally active nonrunners (10 nonrunners and 13 runners within each age-group). Between-group differences and relationships between variables were assessed via ANOVA/ANCOVA and Pearson product-moment correlation coefficients, respectively.

RESULTS

Adjusted aPWV and adjusted AP were similar between runners and nonrunners in both age groups (all, P > 0.05), but higher with age (all, P < 0.001), with a greater effect size for the age-related difference in AP in runners (Hedges' g, 3.6 vs 2.6). aSBP was lower in young (P = 0.009; g = 2.6), but not middle-aged (P = 0.341; g = 1.1), runners compared to nonrunners. MSNA burst frequency did not correlate with AP in either age group (young: r = 0.00, P = 0.994; middle-aged: r = - 0.11, P = 0.604).

CONCLUSION

There is an age-dependent effect of habitual exercise on aortic haemodynamics, with lower aSBP in young runners compared to nonrunners only. Statistical adjustment of aPWV and AP markedly influenced the outcomes of this study, highlighting the importance of performing these analyses. Further, peripheral sympathetic vasomotor outflow and AP were not correlated in young or middle-aged normotensive men.

Kidney Function and Aortic Stiffness, Pulsatility, and Endothelial Function in African Americans: The Jackson Heart Study

Rationale & Objective

The relation of vascular stiffness, endothelial function, and kidney function is incompletely elucidated in African Americans. Our hypothesis was that increased vascular stiffness and endothelial dysfunction are associated with low estimated glomerular filtration rate (eGFR) and albuminuria in African Americans.

Study Design

Cross-sectional cohort analysis of data from the Jackson Heart Study.

Settings & Patients

2,244 Jackson Heart Study participants (2012-2017 after Exam 3) who had undergone noninvasive hemodynamic assessment using arterial tonometry.

Predictors

Baseline carotid-femoral pulse wave velocity, pulsatile hemodynamics forward wave amplitude, and hyperemic brachial artery flow were measured. Reduced eGFR was defined as eGFR between 15 and 60 mL/min/1.73 m².

Outcomes

Prevalent albuminuria, urinary albumin-creatinine ratio.

Analytical Approach

2-sample t test for continuous variables and χ² test for categorical variables in addition to logistic and linear regression models to assess the risk for chronic kidney disease with each proposed hemodynamic variable.

Results

Among 2,244 participants, mean age was 66 ± 11 years and 64% were women. Reduced eGFR was present in 233 (10.4%), and elevated urinary albumin-creatinine ratio, in 232 (10.4%). In multivariable-adjusted analyses, higher carotid-femoral pulse wave velocity was associated with the presence of reduced eGFR (OR, 1.37 [95% CI, 1.08-1.75] per SD; P = 0.01) and with prevalent albuminuria (OR, 1.66 [95% CI, 1.32-2.11]; P < 0.001). Higher forward wave amplitude was significantly associated with prevalent albuminuria (OR, 1.37 [95% CI, 1.14-1.65]; P = 0.001).

Limitations

Cross-sectional analyses cannot inform causality.

Conclusions

Higher arterial stiffness and pulsatility are associated with higher odds of reduced eGFR in African Americans. Future studies should focus on whether improving arterial stiffness contributes to kidney protection in African Americans.

Pulsatile load and wasted pressure effort are reduced following an acute bout of aerobic exercise

Following aerobic exercise, sustained vasodilation and concomitant reductions in total peripheral resistance (TPR) result in a reduction in blood pressure that is maintained for two or more hours. However, the time course for postexercise changes in reflected wave amplitude and other indices of pulsatile load on the left ventricle have not been thoroughly described. Therefore, we tested the hypothesis that reflected wave amplitude is reduced beyond an hour after cycling at 60% V̇o2peak for 60 min. Aortic pressure waveforms were derived in 14 healthy adults (7 men, 7 women; 26 ± 3 yr) from radial pulse waves acquired via high-fidelity applanation tonometry at baseline and every 20 min for 120 min postexercise. Concurrently, left ventricle outflow velocities were acquired via Doppler echocardiography and pressure-flow analyses were performed. Aortic characteristic impedance (Zc), forward (Pf) and backward (Pb) pulse wave amplitude, reflected wave travel time (RWTT), and wasted pressure effort (WPE) were derived. Reductions in aortic blood pressure, Zc, Pf, and Pb were all sustained postexercise whereas increases in RWTT emerged from 60 to 100 min post exercise (all P < 0.05). WPE was reduced by ∼40% from 40 to 100 min post exercise (all P < 0.02). Stepwise multiple regression analysis revealed that the peak ΔWPE was associated with ΔRWTT (β = -0.57, P = 0.003) and ΔPb (β = 0.52, P = 0.006), but not Δcardiac output, ΔTPR, ΔZc, or ΔPf. These results suggest that changes in pulsatile hemodynamics are sustained for ≥100 min following moderate intensity aerobic exercise. Moreover, decreased and delayed reflected pressure waves are associated with decreased left ventricular wasted effort after exercise.NEW & NOTEWORTHY We demonstrate that pulsatile load on the left ventricle is diminished following 60 min of moderate intensity aerobic exercise. During recovery from exercise, the amplitude of the forward and backward traveling pressure waves are attenuated and the arrival of reflected waves is delayed. Thus, the work imposed upon the left ventricle by reflected pressure waves, wasted pressure effort, is decreased after exercise.

Differential responses of resistance arterioles to elevated intraluminal pressure in blacks and whites

Black Americans have an earlier onset, higher average blood pressure, and higher rates of hypertension-related mortality and morbidity, compared to whites. The racial difference may be related to microvasculature, the major regulatory site of blood pressure. The goal of this study was to compare the response of resistance vessels to high intraluminal pressure between black and white participants. A total of 38 vessels were obtained from human fat samples [21 black, 17 white; mean age 32 ± 12 yr and body mass index (BMI) 26.9 ± 4.9; between-group P ≥ 0.05] and included in this study. Internal diameter was measured in response to the flow induced by various pressure gradients (Δ10, Δ20, Δ40, Δ60, and Δ100 cmH₂O), and flow-induced dilation (FID) was calculated before and after high intraluminal pressure (150 cmH₂O). Before high intraluminal pressure, FID was not different between blacks and whites (P = 0.112). After exposure to high intraluminal pressure, FID was reduced at every pressure gradient in vessels from blacks (P < 0.001), whereas FID did not change in white participants except at Δ100 cmH₂O. When incubated with the hydrogen peroxide (H₂O₂) scavenger polyethylene glycol-catalase (PEG-catalase), the FID response in vessels from black, but not white, individuals was significantly reduced and the magnitude was higher at normal pressure relative to high pressure. Our findings suggest that the vessels from self-identified black individuals are more susceptible to microvascular dysfunction following transient periods of high intraluminal pressure compared to whites and show greater dependence on H₂O₂ as a main contributor to FID at normal pressures.NEW & NOTEWORTHY Microvascular function regulates blood pressure and may contribute to racial differences in the incidence and prevalence of hypertension and other cardiovascular diseases. Here, we show that using an ex vivo model of resistance arterioles isolated from human gluteal fat tissue, flow-induced dilation is not different between black and white participants. However, when exposed to transient increases in intraluminal pressure, the flow-induced dilation in resistance arterioles from black participants demonstrated greater reductions relative to their white counterparts, indicating a higher sensitivity to pressure change in the microvasculature.

Race-specific changes in endothelial inflammation and microRNA in response to an acute inflammatory stimulus

Both aberrant vascular reactivity to acute cardiovascular stress and epigenetic mechanisms such as microRNA (miR) may underlie the increased propensity for African Americans (AA) to develop cardiovascular disease. This study assessed racial differences in acute induced endothelial inflammation and related miRs. Cultured human umbilical vein endothelial cells (HUVECs) derived from AA and Caucasian Americans (CA) were exposed to influenza vaccine to determine changes in inflammatory markers, endothelial nitric oxide synthase (eNOS), and miR expression/release. Endothelial function [flow-mediated dilation (FMD)], circulating IL-6, and circulating miR were also measured in young, healthy AA and CA individuals before and after receiving the influenza vaccine. There were no significant racial differences in any parameters at baseline. The vaccine induced increases in IL-6 release (24%, P = 0.02) and ICAM-1 mRNA (40%, P = 0.03), as well as reduced eNOS mRNA (24%, P = 0.04) in AA HUVECs, but not in CA HUVECs (all P > 0.05). Intracellular levels of anti-inflammatory miR-221-3p and miR-222-3p increased specifically in CA HUVECs (72% and 53%, P = 0.04 and P = 0.06), whereas others did not change in either race. HUVEC secretion of several miRs decreased in both races, whereas the release of anti-inflammatory miR-150-5p was decreased only by AA cells (-30%, P = 0.03). In individuals of both races, circulating IL-6 increased approximately twofold 24 h after vaccination (both P < 0.01) and returned to baseline levels by 48 h, whereas FMD remained unchanged. Although macrovascular function was unaffected by acute inflammation in AA and CA individuals, AA endothelial cells exhibited increased susceptibility to acute inflammation and unique changes in related miR.NEW & NOTEWORTHY Used as an acute inflammatory stimulus, the influenza vaccine induced an inflammatory response and decreased eNOS gene expression in endothelial cells derived from African Americans, but not Caucasian Americans. Race-specific changes in intracellular expression and release of specific microRNAs also occurred and may contribute to an exaggerated inflammatory response in African Americans. In vivo, the vaccine caused similar systemic inflammation but had no effect on endothelial function or circulating microRNAs in individuals of either race.

Characterization of the blood pressure response during cycle ergometer cardiopulmonary exercise testing in black and white men : Data from the Fitness Registry and Importance of Exercise: A National Database (FRIEND)

It has been established that blacks have higher overall incidence and prevalence of hypertension compared to their white counterparts. However, the maximum blood pressure (BP) response of blacks to exercise has not been characterized. A total of 5996 apparently healthy men from the Fitness Registry and Importance of Exercise: A National Database (FRIEND) who underwent maximum cardiopulmonary exercise tests on a cycle ergometer were included in this analysis. Of these participants, 1245 (21%) self-identified as black while the remaining 4751 (79%) identified as white. All subjects had a respiratory exchange ratio (RER) of ≥1.0 and had no reports of cardiovascular or pulmonary disease. Systolic BP (BP) response to exercise was indexed according to increase in workload (SBP/MET-slope). Both racial groups were subdivided into age groups by decade. Black men had higher peak SBP and higher SBP/MET-slopes compared to white men across all age groups (p < 0.001). Resting SBP was not different between blacks and whites except within the 18-29-year age group. The differences in peak SBP and SBP/MET-slope between age and race groups indicate that black men have an exaggerated BP response to exercise irrespective of resting BP values. Further investigation is warranted to determine the underlying mechanisms responsible and clinical implications for this exaggerated BP response to exercise.

Effect of acute maximal exercise on vasodilatory function and arterial stiffness in African-American and white adults

INTRODUCTION

African-Americans are at increased risk of cardiovascular disease compared with their white counterparts, potentially due to greater arterial stiffness and reduced vasodilatory capacity. Racial differences also exist in arterial stiffness and blood pressure (BP) following maximal aerobic exercise; African-Americans do not exhibit central post exercise BP reductions. Whether impaired vasodilatory function contributes to the lack of BP response is unknown.

PURPOSE

To evaluate vasodilatory function, arterial stiffness, and hemodynamics following a maximal aerobic exercise test in young, healthy African-American and white adults.

METHODS

Twenty-seven African-American and 35 white adults completed measures at baseline, 15 and 30 min after a maximal exercise test. Measures included vasodilatory capacity of forearm resistance arteries, central pulse wave velocity (PWV), and carotid artery stiffness (β).

RESULTS

Forearm reactive hyperemia was greater in white but increased similarly following exercise in both groups (P < 0.05). Carotid β-stiffness increased at 15 and 30 min (P = 0.03) in both groups, but PWV controlled for mean arterial pressure decreased after maximal exercise (P = 0.03). White exhibited reductions in systolic and mean pressure, whereas no changes were seen for African-Americans (interaction effects: P < 0.05).

CONCLUSION

African-American and white adults had similar decreases in PWV, increases in β-stiffness, and increases in vasodilatory function following maximal exercise. African-American adults, however, did not display reductions in BP and had overall lower vasodilatory function in comparison with white adults. Our results suggest African-Americans exhibit similar vasodilatory function changes following aerobic exercise as their white counterparts, and therefore vasodilatory function likely does not explain the lack of BP response in African-Americans.

Post-exercise Response of Arterial Parameters for Arterial Health Assessment Using a Microfluidic Tactile Sensor and Vibration-Model-Based Analysis: A Proof-of-Concept Study

OBJECTIVE

Arterial stiffness and endothelial function are two established surrogate markers of subclinical atherosclerosis and are quantified by three arterial parameters: elasticity, viscosity and radius of the arterial wall. Yet, the current methods for their assessment are unsuitable for routine use. Post-exercise response of the cardiovascular (CV) system serves as a more sensitive detection of subclinical arterial abnormalities that are not apparent at-rest. The objective of this study is to propose a novel method that can measure post-exercise response of arterial parameters and is also suitable for routine use.

APPROACH

A microfluidic tactile sensor with a location-insensitive configuration was used for arterial pulse signal measurements on six asymptomatic male subjects, offering measurement reliability, ease use by a layperson, and affordability. By treating the arterial pulse signal as a vibration signal of the arterial wall, vibration-model-based analysis of only one measured pulse signal with no calibration was conducted for simultaneous estimation of three arterial parameters. Exercise-intensity-normalized percent changes in arterial parameters were utilized to remove the influence of variation in exercise intensity on post-exercise response, and then their measured values were compared for difference in post-exercise response between the subjects.

MAIN RESULTS

One subject who was obese, on subject who had insomnia, and the oldest subject in the study demonstrated differences in post-exercise response at the radial artery (RA), as compared with the three subjects free of those three factors. Despite a lack of statistical significance, the observed difference at the RA between subjects was supported by (i) their consistency with the related findings in the literature, and (ii) their consistency with the measured values at the carotid artery (CA) and superficial temporal artery (STA) and the anatomical difference between the three arteries.

SIGNIFICANCE

The proposed method has the potential of offering an affordable and convenient diagnosis tool for routine arterial health assessment.

The Acute Effects of High-Intensity Cycling Exercise on Arterial Stiffness in Adolescent Wrestlers

The aim of this study was to determine the acute effects of high‐intensity cycling exercise on the variables of carotid artery compliance, distensibility and beta stiffness index in elite adolescent wrestlers. The subjects were elite athletes competing in national, European and World Championships, who attended a training camp in the province of Kahramanmaras organized by the Turkish Centre for Olympic Preparation. The study sample comprised 31 male elite wrestlers with a mean age of 15.90 ± 0.87 years, body height of 165.97 ± 9.7 cm and body mass of 66.3 ± 18.45 kg. The arterial stiffness variables of the wrestlers were measured with high‐resolution Doppler ultrasonography before and 5 min after 30 s of high‐intensity cycling exercise (the Wingate Anaerobic Cycling test). The results showed a statistically significant correlation between mean power performance and carotid artery compliance at the 5th min after a single cycling sprint exercise (p < 0.05). No correlation was determined between peak power and the arterial stiffness variables (p > 0.05). The study results indicate that acute changes in arterial stiffness variables are associated with the performance level of high‐intensity cycling exercise in a group of elite adolescent wrestlers.

Response of peripheral arterial pulse wave velocity to acute exercise in patients after recent myocardial infarction and healthy controls

Background

Many studies found increased central arterial stiffness and poor endothelial function in patients with coronary artery disease (CAD). Acute exercise has been shown to decrease peripheral pulse wave velocity (pPWV) in young healthy volunteers. We hypothesized the response to acute exercise to be diminished in CAD patients compared to healthy young (HY) and age-matched (HAM) controls.

Methods

In 21 patients after recent myocardial infarction (CAD), 11 HAM and 10 HY pPWV was measured by applanation tonometry at the proximal femoral artery and the posterior tibial artery at rest and from 5 to 15 min after cessation of exhaustive exercise. Heart rate (HR) and blood pressure (BP) were monitored continuously. Resting central PWV (cPWV) was measured between the carotid and femoral arteries. Resting values and reponses to acute exercise were compared between the three groups and predictors for pPWV response were sought.

Results

The response in pPWV to acute exercise seen in HY (lowering in pPWV by 17%) was absent in both CAD and HAM. Resting pPWV was not statistically different between the three groups, while cPWV was comparable in CAD and HAM but 17% lower in HY. Predictors for response in pPWV to exercise were age (Spearman r = 0.48), cPWV (r = 0.34) and response in diastolic BP (r = 0.32).

Conclusion

The response in pPWV to acute exercise observed in HY was absent in CAD and HAM. In dilated peripheral arteries, PWV may reflect stiffness of passive vessel structures, which are likely to increase with age in healthy persons and CAD alike.

Postexercise hypotension in central aortic pressures following walking and its relation to cardiorespiratory fitness

BACKGROUND

Central aortic blood pressure (BP) is reduced after exercise. The aim of this study was to determine whether cardiorespiratory fitness relates to postexercise reductions in aortic BP.

METHODS

Sixteen young adults completed maximal exercise testing for peak oxygen uptake (VO2). Participants walked at a slow (80 steps/min, ~47% maxHR) and fast (125 steps/min, ~65% maxHR) stepping cadence for 3000 steps on two nonconsecutive days. Before and after each walking condition, radial tonometry was used to derive aortic pressures. Measurements after walking were taken after 30 and 60 min of supine recovery.

RESULTS

The change in aortic BP was similar between walking cadences. Aortic systolic BP (-2.3 mmHg, P=0.03) and pulse pressure (-3.2 mmHg, P<0.001) were significantly reduced after 60 min of recovery as compared to baseline. The reduction in aortic pulse pressure was associated with decreased forward (r=0.69, P<0.001) and backward wave pressure (r=0.70, P<0.001). Peak VO2 was not associated (P>0.05) with these changes, but was strongly associated with non-significant changes in aortic systolic BP (30min: r=-0.54, P=0.03) and diastolic BP (30 min: r=-0.64, 60 min: r=-0.77; both P<0.01) after slow walking only.

CONCLUSIONS

These results indicate that cardiorespiratory fitness associates with aortic pressure reductions after walking dependent on exercise intensity.

Racial Disparities in Arterial Stiffness Between Healthy Whites and African Americans in the United States: A Meta-analysis

BACKGROUND

African Americans (AAs) present with cardiovascular disease (CVD) risk factors at younger ages than whites. Consequently, CVD and stroke occur at a higher incidence and at earlier decades in life in AA populations. Arterial stiffness is a predictor of CVD outcomes and partially explains the CVD risk experienced by racial minorities. We evaluated the differences in arterial stiffness observed in AAs and whites through a systematic review and meta-analysis.

METHODS

We searched PubMed and SCOPUS for comparative studies published March 1995 to November 29, 2017 comparing arterial stiffness assessments (pulse wave velocity, augmentation index, and central blood pressure) between AAs and whites. Two independent reviewers examined 195 titles/abstracts, 85 full text articles and 11 articles were included in the meta-analysis using random effects modeling approaches.

MAIN RESULTS

A total of 5060 white and 3225 AAs were included across 11 relevant studies. Carotid-femoral pulse wave velocity (cfPWV) measures were statistically different between AAs and whites (mean difference = -0.44, 95% confidence interval [CI]: -[-0.67, -0.21], p = 0.0002). Aortic femoral pulse wave velocity was significantly different between AAs and whites (mean difference = -0.21, [95% CI] -0.35, -0.07, p = 0.003) regardless of sex. Augmentation index (AIx) and Augmentation index at a 75 beats per minutes heart rate (AIx @75) was also significantly different between AA and whites (mean difference = -4.36 [95% CI] = -6.59, -2,12, p = 0.0001 and -6.26, [95% CI] = -9.19, -3.33, p < 0.0001, respectively).

CONCLUSIONS

Racial disparities in arterial stiffness persist among African American racial groups in the United States. The lack of homogeneity in studies capturing racial disparities in cfPWV suggest that additional studies are needed to understand the magnitude of racial differences in African Americans and whites that might be clinically relevant.

Acute Effects of Exercise Mode on Arterial Stiffness and Wave Reflection in Healthy Young Adults: A Systematic Review and Meta-Analysis

Background: This systematic review and meta-analysis quantified the effect of acute exercise mode on arterial stiffness and wave reflection measures including carotid-femoral pulse wave velocity (cf-PWV), augmentation index (AIx), and heart rate corrected AIx (AIx75). Methods: Using standardized terms, database searches from inception until 2017 identified 45 studies. Eligible studies included acute aerobic and/or resistance exercise in healthy adults, pre- and post-intervention measurements or change values, and described their study design. Data from included studies were analyzed and reported in accordance with the Cochrane Handbook for Systematic Reviews of Interventions and PRISMA guidelines. Meta-analytical data were reported via forest plots using absolute differences with 95% confidence intervals with the random effects model accounting for between-study heterogeneity. Reporting bias was assessed via funnel plots and, individual studies were evaluated for bias using the Cochrane Collaboration's tool for assessing risk of bias. A modified PEDro Scale was applied to appraise methodological concerns inherent to included studies. Results: Acute aerobic exercise failed to change cf-PWV (mean difference: 0.00 ms^-1 [95% confidence interval: -0.11, 0.11], p = 0.96), significantly reduced AIx (-4.54% [-7.05, -2.04], p = 0.0004) and significantly increased AIx75 (3.58% [0.56, 6.61], p = 0.02). Contrastingly, acute resistance exercise significantly increased cf-PWV (0.42 ms^-1 [0.17, 0.66], p = 0.0008), did not change AIx (1.63% [-3.83, 7.09], p = 0.56), and significantly increased AIx75 (15.02% [8.71, 21.33], p < 0.00001). Significant heterogeneity was evident within all comparisons except cf-PWV following resistance exercise, and several methodological concerns including low applicability of exercise protocols and lack of control intervention were identified. Conclusions: Distinct arterial stiffness and wave reflection responses were identified following acute exercise with overall increases in both cf-PWV and AIx75 following resistance exercise potentially arising fromcardiovascular and non-cardiovascular factors that likely differ from those following aerobic exercise. Future studies should address identified methodological limitations to enhance interpretation and applicability of arterial stiffness and wave reflection indices to exercise and health.

The effect of acute maximal exercise on postexercise hemodynamics and central arterial stiffness in obese and normal-weight individuals

Central arterial stiffness is associated with incident hypertension and negative cardiovascular outcomes. Obese individuals have higher central blood pressure (BP) and central arterial stiffness than their normal‐weight counterparts, but it is unclear whether obesity also affects hemodynamics and central arterial stiffness after maximal exercise. We evaluated central hemodynamics and arterial stiffness during recovery from acute maximal aerobic exercise in obese and normal‐weight individuals. Forty‐six normal‐weight and twenty‐one obese individuals underwent measurements of central BP and central arterial stiffness at rest and 15 and 30 min following acute maximal exercise. Central BP and normalized augmentation index (AIx@75) were derived from radial artery applanation tonometry, and central arterial stiffness was obtained via carotid‐femoral pulse wave velocity (cPWV) and corrected for central mean arterial pressure (cPWV/cMAP). Central arterial stiffness increased in obese individuals but decreased in normal‐weight individuals following acute maximal exercise, after adjusting for fitness. Obese individuals also exhibited an overall higher central BP (P < 0.05), with no exercise effect. The increase in heart rate was greater in obese versus normal‐weight individuals following exercise (P < 0.05), but there was no group differences or exercise effect for AIx@75. In conclusion, obese (but not normal‐weight) individuals increased central arterial stiffness following acute maximal exercise. An assessment of arterial stiffness response to acute exercise may serve a useful detection tool for subclinical vascular dysfunction.

Effects of Obesity and Hypertension on Pulse Wave Velocity in Children

Pulse wave velocity (PWV) is a biomarker of arterial stiffness. Findings from prior studies are conflicting regarding the impact of obesity on PWV in children. The authors measured carotid-femoral PWV in 159 children aged 4 to 18 years, of whom 95 were healthy, 25 were obese, 15 had hypertension (HTN), and 24 were both obese and hypertensive. Mean PWV increased with age but did not differ by race or sex. In adjusted analyses in children 10 years and older (n=102), PWV was significantly higher in children with hypertension (PWV±standard deviation, 4.9±0.7 m/s), obesity (5.0±0.9 m/s), and combined obesity-hypertension (5.2±0.6 m/s) vs healthy children (4.3±0.7 m/s) (each group, P<.001 vs control). In our study, obesity and HTN both significantly and independently increased PWV, while African American children did not have a higher PWV than Caucasian children.

No Evidence of Racial Differences in Endothelial Function and Exercise Blood Flow in Young, Healthy Males Following Acute Antioxidant Supplementation

This study investigated the effects of acute antioxidant supplementation on endothelial function, exercise blood flow and oxidative stress biomarkers in 9 young African American compared to 10 Caucasian males (25.7±1.2 years). We hypothesized that African American males would have lower exercise blood flow and endothelial responsiveness compared to Caucasian males, and these responses would be improved following antioxidant supplementation. Ultrasonography was used to measure blood flow during handgrip exercise. Endothelial function was assessed using flow-mediated dilation, and lipid peroxidation was assessed by measuring levels of malondialdehyde-thiobarbituric acid reactive substances. African American males exhibited lower endothelial function than Caucasians at baseline (8.3±1.7 vs. 12.2±1.7%) and the difference was ameliorated with antioxidant supplementation (10.7±1.9% vs. 10.8±1.8%), but the interaction was not significant (p=0.10). There were no significant changes in malondialdehyde-thiobarbituric acid reactive substances following antioxidant supplementation. There was a significant increase in brachial blood flow and forearm vascular conductance with exercise but no differences with antioxidant supplementation. There were no group differences in exercise responses and no differences with antioxidant supplementation, suggesting a lack of influence of oxidative stress during exercise in this cohort.

Effect of acute aerobic exercise and histamine receptor blockade on arterial stiffness in African Americans and Caucasians

African Americans (AA) exhibit exaggerated central blood pressure (BP) and arterial stiffness measured by pulse wave velocity (PWV) in response to an acute bout of maximal exercise compared with Caucasians (CA). However, whether potential racial differences exist in central BP, elastic, or muscular arterial distensibility after submaximal aerobic exercise remains unknown. Histamine receptor activation mediates sustained postexercise hyperemia in CA but the effect on arterial stiffness is unknown. This study sought to determine the effects of an acute bout of aerobic exercise on central BP and arterial stiffness and the role of histamine receptors, in AA and CA. Forty-nine (22 AA, 27 CA) young and healthy subjects completed the study. Subjects were randomly assigned to take either histamine receptor antagonist or control placebo. Central blood BP and arterial stiffness measurements were obtained at baseline, and at 30, 60, and 90 min after 45 min of moderate treadmill exercise. AA exhibited greater central diastolic BP, elevated brachial PWV, and local carotid arterial stiffness after an acute bout of submaximal exercise compared with CA, which may contribute to their higher risk of cardiovascular disease. Unexpectedly, histamine receptor blockade did not affect central BP or PWV in AA or CA after exercise, but it may play a role in mediating local carotid arterial stiffness. Furthermore, histamine may mediate postexercise carotid arterial dilation in CA but not in AA. These observations provide evidence that young and healthy AA exhibit an exaggerated hemodynamic response to exercise and attenuated vasodilator response compared with CA.NEW & NOTEWORTHY African Americans are at greater risk for developing cardiovascular disease than Caucasians. We are the first to show that young and healthy African Americans exhibit greater central blood pressure, elevated brachial stiffness, and local carotid arterial stiffness following an acute bout of submaximal exercise compared with Caucasians, which may contribute to their higher risk of cardiovascular disease. Furthermore, African Americans exhibit attenuated vasodilator response compared with Caucasians.

A systematic review on the effect of acute aerobic exercise on arterial stiffness reveals a differential response in the upper and lower arterial segments

The objective of this systematic review was to provide insight into the controversy that still abounds as to the impact of acute aerobic exercise on immediate changes in arterial stiffness. Electronic databases were searched to identify articles assessing the effects of acute aerobic exercise on parameters of arterial stiffness. Eligible studies included arterial stiffness measurements before and after acute aerobic exercise in healthy human subjects. Forty-three studies were included. The effect of acute aerobic exercise on arterial stiffness was found to be dependent on the anatomical segment assessed, and on the timing of the measurement post-exercise. Arterial stiffness of the central and upper body peripheral arterial segments was found to be increased relative to resting values immediately post-exercise (0-5 min), whereas, thereafter (>5 min), decreased to a level at or below resting values. In the lower limbs, proximal to the primary working muscles, arterial stiffness decreased immediately post-exercise (0-5 min), which persisted into the recovery period post-exercise (>5 min). This systematic review reveals a differential response to acute exercise in the lower and upper/central arterial segments in healthy adult subjects. We further showed that the effect of acute aerobic exercise on arterial stiffness is dependent on the timing of the measurements post-exercise. Therefore, when assessing the overall impact of exercise on arterial stiffness, it is important to consider the arterial segment being analyzed and measurement time point, as failure to contextualize the measurement can lead to conflicting results and misleading clinical inferences.

Arterial hemodynamics are impaired at rest and following acute exercise in overweight young men

Higher body mass index (BMI) is associated with greater cardiovascular disease (CVD) risk, in part due to aortic stiffening assessed by carotid-femoral pulse wave velocity (cfPWV). Importantly, greater cardiorespiratory fitness (CRF; VO2peak) decreases CVD risk, and is associated with reductions in aortic stiffness. We tested the hypothesis that young adult overweight (OW, n=17) compared with healthy-weight (HW, n=17) men will have greater resting aortic stiffness, reduced CRF and an impaired post-exercise hemodynamic response. Resting cfPWV was greater in OW versus HW individuals (5.81 ± 0.13 vs 4.81 ± 0.12 m/sec, p<0.05). Relative CRF (VO2peak; mL/kg/min) was lower in OW compared with HW individuals (49.4 ± 1.3 vs 57.6 ± 1.0 mL/kg/min, p<0.05), and was inversely related with cfPWV ( p<0.05). However, CRF as absolute VO2peak (L/min) was not different between groups and there was no relation between cfPWV and absolute VO2peak (L/min), indicating reduced relative CRF in OW men is due to greater body mass. Following the maximal treadmill exercise test, cfPWV was greater in OW compared with HW subjects from rest to 60 minutes post-exercise ( p<0.05). Compared with HW, OW individuals had higher systolic blood pressure (main effect, p<0.05) and diastolic blood pressure was selectively increased for up to 60 minutes following exercise ( p<0.05). Overweight individuals had an attenuated post-exercise decrease in mean arterial pressure ( p<0.05). Collectively, these results indicate that young, apparently healthy, OW men have greater resting aortic stiffening and an impaired post-exercise hemodynamic response.

Aerobic Exercise Training and Arterial Changes in African Americans versus Caucasians

African Americans (AA) have increased carotid artery intima-media thickness and decreased vascular function compared with their Caucasian (CA) peers. Aerobic exercise prevents and potentially reverses arterial dysfunction.

PURPOSE

The purpose of this study was to examine the effect of 8 wk of moderate- to high-intensity aerobic training in young healthy sedentary AA and CA men and women.

METHODS

Sixty-four healthy volunteers (men, 28; women, 36) with mean age 24 yr underwent measures of arterial structure, function, and blood pressure (BP) variables at baseline, after the 4-wk control period, and 8 wk after training.

RESULTS

There was a significant increase in VO2peak among both groups after exercise training. Brachial systolic BP decreased significantly after the control period in both groups but not after exercise training. Carotid pulse pressure decreased significantly in both groups after exercise training as compared with that in baseline. There was no change in any of the other BP variables. AA had higher intima-media thickness at baseline and after the control period but it significantly decreased after exercise training compared with that of CA. AA had significantly lower baseline forearm blood flow and reactive hyperemia compared with those of CA, but exercise training had no effect on these variables. There was no significant difference in arterial stiffness (central pulse wave velocity) and wave-reflection (augmentation index) between the two groups at any time point.

CONCLUSIONS

This is the first study to show that 8 wk of aerobic exercise training causes significant improvement in the arterial structure in young, healthy AA, making it comparable with the CA and with minimal effects on BP variables.

Post-exercise effects on aortic wave reflection derived from wave separation analysis in young- to middle-aged pre-hypertensives and hypertensives

PURPOSE

Decreases in brachial blood pressure (BP) may occur for several hours following a bout of exercise. Although aortic backward waves predict cardiovascular damage independent of brachial BP, whether decreases in aortic backward waves also occur post-exercise in young-to-middle-aged hypertensives, the extent to which these changes exceed brachial BP changes, and the best method of identifying these changes is uncertain.

METHODS

We examined aortic function at baseline and 15-min post-exercise in 20 pre-hypertensive or hypertensive men and women (age 45 ± 7 years). Central aortic pressure, forward (Pf) and backward (Pb) wave pressures, the reflection index (RI) and augmentation pressure (AP) and index (AIx) were determined using applanation tonometry, and SphygmoCor software.

RESULTS

Decreases in central aortic (p < 0.001) but not brachial systolic BP and pulse pressure (PP) occurred post-exercise. In addition, decreases in post-exercise (baseline versus post-exercise) Pb (19 ± 4 vs 13 ± 3 mm Hg p < 0.0001), RI (72.9 ± 22.1 vs 47.6 ± 12.8 %, p < 0.0001), AIx (26.3 ± 10.8 vs 7.8 ± 11.6 %, p < 0.0001) and AP (9.9 ± 3.9 vs 2.8 ± 3.9 mm Hg, p < 0.0001), but not Pf, were noted. However, decreases in AIx were not correlated with decreases in Pb, and whilst decreases in aortic PP correlated with decreases in Pb (p < 0.0001), no correlations were noted with decreases in AP or AIx.

CONCLUSION

In young-to-middle-aged pre-hypertensive and hypertensive individuals, aortic backward waves decrease post-exercise; this change is not reflected in brachial BP measurements and is poorly indexed by measures of pressure augmentation.

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 contribution 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 control 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 following 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 volume in BL. The heightened BP and vascular responses to exercise stimulus is consistent with the greater CVD risk in BL.

The acute effect of maximal exercise on central and peripheral arterial stiffness indices and hemodynamics in children and adults

This study compared the effects of a bout of maximal running exercise on arterial stiffness in children and adults. Right carotid blood pressure and artery stiffness indices measured by pulse wave velocity (PWV), compliance and distensibility coefficients, stiffness index α and β (echo-tracking), contralateral carotid blood pressure, and upper and lower limb and central/aortic PWV (applanation tonometry) were taken at rest and 10 min after a bout of maximal treadmill running in 34 children (7.38 ± 0.38 years) and 45 young adults (25.22 ± 0.91 years) having similar aerobic potential. Two-by-two repeated measures analysis of variance and analysis of covariance were used to detect differences with exercise between groups. Carotid pulse pressure (PP; η(2) = 0.394) increased more in adults after exercise (p < 0.05). Compliance (η(2) = 0.385) decreased in particular in adults and in those with high changes in distending pressure, similarly to stiffness index α and β. Carotid PWV increased more in adults and was related to local changes in PP but not mean arterial pressure (MAP). Stiffness in the lower limbs decreased (η(2) = 0.115) but apparently only in those with small MAP changes (η(2) = 0.111). No significant exercise or group interaction effects were found when variables were adjusted to height. An acute bout of maximal exercise can alter arterial stiffness and hemodynamics in the carotid artery and within the active muscle beds. Arterial stiffness and hemodynamic response to metabolic demands during exercise in children simply reflect their smaller body size and may not indicate a particular physiological difference compared with adults.

Systolic blood pressure response after high-intensity interval exercise is independently related to decreased small arterial elasticity in normotensive African American women

Aerobic exercise transiently lowers blood pressure. However, limited research has concurrently evaluated blood pressure and small arterial elasticity (SAE), an index of endothelial function, among African American (AA) and European American (EA) women the morning after (i.e., ≈22 h later) acute bouts of moderate-intensity continuous (MIC) and high-intensity interval (HII) exercise matched for total work. Because of greater gradients of shear stress, it was hypothesized that HII exercise would elicit a greater reduction in systolic blood pressure (SBP) compared to MIC exercise. After baseline, 22 AA and EA women initiated aerobic exercise training 3 times/week. Beginning at week 8, three follow-up assessments were conducted over the next 8 weeks at random to measure resting blood pressure and SAE. In total all participants completed 16 weeks of training. Follow-up evaluations were made: (i) in the trained state (TS; 8-16 weeks of aerobic training); (ii) ≈22 h after an acute bout of MIC exercise; and (iii) ≈22 h after an acute bout of HII exercise. Among AAs, the acute bout of HII exercise incited a significant increase in SBP (mm Hg) (TS, 121 ± 14 versus HII, 128 ± 14; p = 0.01) whereas responses (TS, 116 ± 12 versus HII, 113 ± 9; p = 0.34) did not differ in EAs. After adjusting for race, changes in SAE were associated (partial r = -0.533; p = 0.01) with changes in SBP following HII exercise. These data demonstrate an acute, unaccustomed bout of HII exercise produces physiological perturbations resulting in a significant increase in SBP that are independently associated with decreased SAE among AA women, but not EA women.

Acute effects of submaximal endurance training on arterial stiffness in healthy middle- and long-distance runners

Measures of arterial stiffness are indicators for cardiovascular health and predictors of cardiovascular events. Arterial stiffness is responsive to acute physiologic stressors such as exercise. However, the acute effects of intensive exercise and recovery on arterial stiffness are controversial. Thirty-seven healthy middle- and long-distance runners (33 men, mean age 26.5±6.6 years) underwent evaluation of their cardiovascular stiffness at rest, after a 15-minute warm-up, immediately after vigorous running 3 km at the pace of their 10-km personal best, and finally 30 minutes after terminating their workout. Peripheral and central systolic blood pressure, as well as augmentation index and pulse wave velocity (PWV), increased during exercise in comparison to baseline (P<.001, general linear model). Thirty minutes after terminating the workout, a drop in peripheral blood pressure (P<.001), central blood pressure (P<.001), and PWV (P=.001) below baseline was observed. Therefore, the authors found that exercise of either moderate or vigorous intensity causes a temporary increase in arterial stiffness in middle- and long-distance runners.

Effects of acute and chronic exercise in patients with essential hypertension: benefits and risks

The importance of regular physical activity in essential hypertension has been extensively investigated over the last decades and has emerged as a major modifiable factor contributing to optimal blood pressure control. Aerobic exercise exerts its beneficial effects on the cardiovascular system by promoting traditional cardiovascular risk factor regulation, as well as by favorably regulating sympathetic nervous system (SNS) activity, molecular effects, cardiac, and vascular function. Benefits of resistance exercise need further validation. On the other hand, acute exercise is now an established trigger of acute cardiac events. A number of possible pathophysiological links have been proposed, including SNS, vascular function, coagulation, fibrinolysis, and platelet function. In order to fully interpret this knowledge into clinical practice, we need to better understand the role of exercise intensity and duration in this pathophysiological cascade and in special populations. Further studies in hypertensive patients are also warranted in order to clarify the possibly favorable effect of antihypertensive treatment on exercise-induced effects.

Influence of single bout of aerobic exercise on aortic pulse pressure

PURPOSE

Regular aerobic exercise has come to the forefront of non-pharmacological treatment for hypertension. In this line, post-exercise hypotension may have a potential tool for efficient blood pressure management. However, less is known about the influence of acute aerobic exercise on aortic pulse pressure (PP), an important property underlying the pathophysiology of cardiovascular disease. We tested the hypotheses that aortic PP would be attenuated with a single aerobic exercise and that its extent would be associated with the delayed return of reflected wave and the leg vasodilatory capacity.

METHODS

In 23 apparent healthy men (22 ± 4 years), hemodynamic variables and aortic pulse wave velocity (PWV) were measured before and 20 and 50 min after a 60-min bout of cycling exercise at moderate intensity (corresponding to 65-75 % heart rate reserve). Aortic pressure was estimated from applanation tonometrically measured radial arterial pressure waveform via general transfer function. Peak calf vascular dilatory capacity was measured with the ischemic exercise-induced hyperemia (via venous occlusion plethysmography).

RESULTS

Finger, brachial, and aortic PP were significantly attenuated following the exercise. At 20 min after the exercise cessation, individual changes in aortic PWV significantly correlated with corresponding changes in aortic PP (r = 0.541, P < 0.05), but this correlation was no longer significant at 50 min after the exercise cessation. Peak calf vascular dilatory capacity was not associated with change in aortic PP.

CONCLUSIONS

We conclude that in young men the aortic PP would be attenuated with the moderate-intensity dynamic exercise partly due to the delayed return of reflection wave from periphery.

Blood pressure changes following aerobic exercise in Caucasian and Chinese descendants

Acute aerobic exercise produces post-exercise hypotension (PEH). Chinese populations have lower prevalence of cardiovascular disease compared to Caucasians. PEH may be associated cardiovascular disease through its influence on hypertension. The purpose of this study was to compare PEH between Caucasian and Chinese subjects following acute aerobic exercise. 62 (30 Caucasian and 32 Chinese, 50% male) subjects underwent measurement of peripheral and central hemodynamics as well as arterial and cardiac evaluations, 30 min and 60 min after 45 min of treadmill exercise. Caucasians exhibited significantly higher baseline BP than the Chinese. While the reduction in brachial artery systolic BP was greater in Caucasian than in the Chinese, there was no difference in changes in carotid systolic BP between the groups. The increase in cardiac output and heart rate was greater in the Chinese than Caucasians, but total peripheral resistance and leg pulse wave velocity decreased by a similar magnitude in the Chinese and Caucasian subjects. We conclude that acute aerobic exercise produces a greater magnitude of PEH in peripheral systolic BP in Caucasian compared to Chinese subjects. The different magnitude in PEH was caused by the greater increase in cardiac output mediated by heart rate, with no change in stroke volume. It is possible that initial BP differences between races influenced the findings.

Exercise-induced pulse wave velocity changes in untreated patients with essential hypertension: the effect of an angiotensin receptor antagonist

This study investigates arterial stiffness changes after acute exercise in young patients with untreated, recently diagnosed grade I essential hypertension (UH) compared with normotensive (NT) individuals and the effect of antihypertensive treatment on this phenomenon. Study 1 consisted of 25 UH and 15 NT patients. UH patients who received treatment were included in study 2 and were followed-up after a 3-month treatment period with an angiotensin II receptor blocker. Aortic pulse wave velocity (PWV) was assessed at baseline, at maximal exercise, and at 10, 30, and 60 minutes later. In UH patients, PWV increased significantly at maximal exercise and 10 and 30 minutes of recovery, despite blood pressure fall to baseline levels. No significant PWV changes were observed in NT patients. Post-treatment PWV levels were significantly decreased and similar to those of NT patients. Arterial stiffness is impaired following high-intensity acute exercise even in the early stages of hypertension. Antihypertensive treatment ameliorates these effects.