Resistance exercise performance variability at submaximal intensities in older and younger adults

Gregory J Grosicki,1 Michael E Miller,2 Anthony P Marsh1 1Department of Health and Exercise Science, Wake Forest University, Winston-Salem, NC, USA; 2Department of Biostatistical Sciences, Division of Public Health Sciences, Wake Forest University School of Medicine, Winston-Salem, NC, USA Abstract: We assessed the variability in the number of repetitions completed at submaximal loads in three resistance tasks in older (N=32, 16 female, 74.3±5.4 years) and younger (N=16, 8 female, 22.8±1.8 years) men and women. One repetition maximum (1RM) was determined on two separate visits on three tasks: leg press (LP), leg extension (LE), and bicep curl (BC). Subjects then completed repetitions to failure on each of the three tasks during two visits, a minimum of 48 hours apart, at either 60% 1RM or 80% 1RM. High reliability for all 1RM assessments was observed. Greater muscular strength was observed in younger compared to older men and women on all tasks (P<0.05). At both 60% and 80% 1RM, considerable interindividual variability was observed in the number of repetitions completed. However, the average number of repetitions completed by younger and older men and women at 60% and 80% 1RM in each of the three tasks was similar, with the only significant difference occurring between younger and older men at 80% 1RM on the leg press (P=0.0258). We did not observe any abnormal blood pressure responses to either the 1RM testing or maximal repetition testing sessions. Considerable interindividual variability was observed in the number of repetitions completed by younger and older men and women at relative intensities typical of resistance training programs. Practitioners should give consideration to individual variability when attempting to maximize the benefits of resistance training. Keywords: resistance exercise, exercise prescription, relative intensity, reliability, older adults, blood pressur

ACUTE EFFECT OF SMARTPHONE APPLICATION GUIDED BREATHING ON BLOOD PRESSURE, BAROREFLEX SENSITIVITY, AND AORTIC STIFFNESS

Joseph D. Vondrasek1, Brett L. Cross1,,2, Gregory J. Grosicki1, Andrew A. Flatt1. 1Georgia Southern University, Savannah, GA. 2Florida State University, Tallahassee, FL. BACKGROUND: Blood pressure (BP), baroreflex sensitivity (BRS), and central arterial stiffness (carotid-femoral pulse wave velocity, cf-PWV) are health markers associated with cardiovascular disease risk, and cost-effective methods for optimizing these metrics are desirable. Previously, device-guided paced breathing improved BP, BRS, and cf-PWV, but there may be a cost barrier for some consumers. Free smartphone applications (app) with breathing guidance are widely available and may be a cost-effective means to improve BP, BRS, and cf-PWV. Therefore, we evaluated the acute cardiovascular effects of paced breathing using a cost-free app. METHODS: Twenty-one apparently healthy young adults (13M:9F; Age: 23.1 ± 3.7 yrs; body mass index: 23.5 ± 2.0 kg/m2) performed 10 min of spontaneous breathing (CTRL) and 10 min of app-guided paced (PACE) breathing (supine, 6 breaths∙min-1; 5-s inhale, 5-s exhale) in a counterbalanced order. Ten min of stabilization preceded both conditions, and 3 min of standing served as a washout period between conditions. BP and cf-PWV were measured immediately before and after each condition using a SphygmoCor XCEL. During each condition, R-R intervals were recorded via electrocardiography and beat-to-beat BP via a continuous non-invasive arterial pressure monitor. Cardiovagal BRS was determined using the sequence method (≥ 3 cycles, ± 4 ms, ± 1 mmHg, R2 ≥ 0.85). Two-way repeated measures analysis of variance was used to assess pre- and post-condition measures (BP, cf-PWV), and a paired t-test was used to compare BRS between conditions. RESULTS: There were no time×condition interactions for systolic or diastolic BP (P \u3e 0.05). There was a time×condition interaction for cf-PWV (P = 0.02). Cf-PWV increased (P = 0.018, d = 0.25) from pre-PACE (5.8 ± 0.8 m/s) to post-PACE (6.0 ± 0.7 m/s), whereas no change (P \u3e 0.05, d = 0.00) occurred from pre-CTRL (5.7 ± 0.7 m/s) to post-CTRL (5.7 ± 0.7 m/s). A total of 14/22 participants met criteria for BRS, which was higher (P = 0.02, d = 0.94) during PACE (26.4 ± 10.8 ms/mmHg) vs. CTRL (19.3 ± 7.5 ms/mmHg). CONCLUSIONS: In young adults, paced breathing guided by a free app promoted acute increases in BRS while minimally affecting BP. Arterial stiffness statistically increased during PACE, but the magnitude of change was well below previously reported clinical meaningfulness (± 0.5 m/s) or minimal detectable change thresholds (± 0.411 m/s)

HEART RATE VARIABILITY AND AEROBIC FITNESS ARE INDEPENDENTLY ASSOCIATED WITH AORTIC STIFFNESS IN YOUNG ADULTS

Joseph D. Vondrasek, Nate K. McMillan, Meral N. Culver, Gregory J. Grosicki, Andrew A. Flatt. Georgia Southern University, Savannah, GA. BACKGROUND: Aortic stiffening, indexed by carotid-femoral pulse wave velocity (cf-PWV), is associated with an increased risk of cardiovascular disease. Aerobic fitness, indexed by maximal oxygen uptake (VO2max) and cardiac-parasympathetic modulation, indexed by vagal-mediated heart rate variability (HRV), have been shown to be inversely associated with cf-PWV. However, collinearity between VO2max and HRV may be influencing the bivariate associations with PWV. PURPOSE: To determine if VO2max and HRV are independently associated with cf-PWV in healthy young adults when included in a multivariate analysis. METHODS: Twenty-one men (24±5 years; 24±17% body fat) and 20 women (21±3 years; 34±7% body fat) recorded ultra-short (i.e., 60-s), post-waking supine HRV measures for 7 days via a Bluetooth heart rate monitor and cost-free smartphone application. The week average of the natural log of the root-mean square of successive normal RR interval differences (LnRMSSD) was recorded for analysis. Participants subsequently reported to the laboratory in a fasted state during morning hours for assessment of cf-PWV via applanation tonometry and VO2max via a graded exercise test on a cycle ergometer. RESULTS: Men had greater (P \u3c0.05) VO2max (39.5±6.4 vs. 28.1±5.9 mL·kg·min-1) and LnRMSSD (4.4 ± 0.3 vs 4.1 ± 0.5) than women, whereas cf-PWV did not reach significance (6.2±0.8 vs. 5.8±0.5, P = 0.06). VO2max, and LnRMSSD were associated (P \u3c0.05) with cf-PWV in men (r = -0.50 and -0.62, respectively) and women (r = -0.58 and -0.53, respectively). Standard least squares regression was performed to predict cf-PWV based on VO2max, LnRMSSD, and sex. A significant model effect was observed (P = 0.002, R2 = 0.41). VO2max (β = -0.44), LnRMSSD (β = -0.35), and sex (β = 0.70) were significant predictors of cf-PWV (P \u3c0.05). Variance inflation factors were all \u3c3.0. CONCLUSIONS: Aerobic fitness, self-recorded ultra-short HRV, and sex were independently predictive of PWV. Lifestyle factors targeted at increasing HRV or increasing aerobic fitness may augment arterial compliance in young adults, thereby reducing long-term risk for cardiovascular disease

COMPARISION OF CENTRAL HEMODYNAMICS, ARTERIAL STIFFNESS, AND CARDIO-AUTONOMIC INDICES BETWEEN HEALTHY YOUNG MALES AND FEMALES

Brett L. Cross, Meral N. Culver, Nate K. McMillan, Andrew A. Flatt, Gregory J. Grosicki. Georgia Southern University (Armstrong), Savannah, GA. Cardiovascular disease (CVD) is the leading cause of death globally. Uncontrolled high blood pressure, largely owing to non-compliant vasculature, is a leading risk factor for CVD. Further, males are disproportionately affected by CVD, but whether detriments in blood pressure and arterial stiffness at a young age contribute to this phenomenon is uncertain. PURPOSE: To compare central hemodynamics, arterial stiffness, and cardio-autonomic indices between apparently healthy young males and females. METHODS: Eleven males (25.5±4 yrs; BMI 25.3±3 kg/m2) and 12 females (22.3±2 yrs; BMI 25.3±5 kg/m2) made 2 visits to the laboratory (2-14 days apart) during morning hours following a 12-hour fast. After 10 minutes of supine rest, central blood pressure was assessed via pulse waveform analysis. Applanation tonometry was used to acquire carotid-femoral pulse wave velocity (cf-PWV; a non-invasive index of arterial stiffness). A Continuous Non-invasive Arterial Pressure device was used to measure beat-to-beat blood pressure changes over a 5-minute period to assess blood pressure variability (average real variability, successive variation, and blood pressure standard deviation (BPSD)) and cardiovagal baroreflex sensitivity (BRS). Sequences of at least 3 consecutive cardiac cycles in which changes in systolic pressure (≥1mmHg) and R-R interval (≥4ms) were the same were identified for BRS analysis. The mean values from the 2 visits were used to perform sex comparisons via independent t-tests. RESULTS: Aortic systolic pressure was greater (P=0.023) in males (107.0±7mmHg) than females (99.9±7mmHg). Similarly, cf-PWV was greater (P=0.017) in males (6.22±1m/s) than females (5.48±1m/s), however when mean arterial pressure was controlled for the results were inconclusive (P=0.05). Systolic BPSD was greater (P=0.028) in females (6.58±1mmHg) than males (5.35±1mmHg). An insufficient number of subjects (n=6) met criteria for BRS analysis. CONCLUSIONS: We observed higher blood pressure and greater aortic stiffness in apparently healthy young males vs females, changes that may precede the development of CVD. Unexpectedly, females exhibited greater BPSD, however this method has been criticized as it fails to account for beat-to-beat blood pressure variation. Observation periods of 5 minutes were inadequate to obtain viable BRS data using liberal sequence inclusion criteria, portending to the need for extended data collection sessions

ARTERIAL STIFFNESS RESPONSES TO A SHORT DURATION, HIGH-INTENSITY SIMULATED FIRE ATTACK IN MALE CAREER FIREFIGHTERS

Tom Nagel1, Bridget Melton1, Wesley T. Blumenburg2, Brett L. Cross2, Greg J. Grosicki2. 1Georgia Southern University, Statesboro, GA. 2Georgia Southern University, Savannah, GA. BACKGROUND: Cardiovascular events are the leading cause of death in firefighters, and nearly two-thirds of these deaths occur during or immediately following a fire suppression event. Arterial stiffness is an independent predictor of cardiovascular-specific and all-cause mortality that may be increased by a fire attack. PURPOSE: To characterize changes in central arterial stiffness, indexed as carotid-femoral pulse wave velocity (cf-PWV), and peripheral arterial stiffness, indexed as Augmentation Index (AIx), following a simulated fire attack. METHODS: Twenty-one male career firefighters (35±8 yrs; 31±5 kg/m2) reported to the testing facility in a fasted state during morning hours. After 10 minutes of supine rest, blood pressure was assessed via a brachial cuff and AIx and cf-PWV were determined via pulse waveform analysis and carotid applanation tonometry, respectively. Firefighters then participated in a seven-station simulated fire attack for time, and heart rate was continuously monitored via wireless telemetry. Brachial blood pressure, AIx, and cf-PWV were reacquired immediately upon completion. Paired t-tests were used to compare pre-post changes in blood pressure and arterial stiffness indices, and Pearson’s correlations were used to explore predictors of arterial stiffness responses. RESULTS: Average heart rate during the simulated fire attack was 164±13 bpm, and average time to completion, a surrogate for fitness, was 8.7±1.7 min. Despite significant increases (p\u3c0.01) in mean arterial pressure (94±9 vs. 115±10 mmHG) following the simulated fire attack, cf-PWV (7.6±1.0 vs. 7.8±0.9 m/s; p=0.34) and AIx (13.8±8.6 vs. 13.9±12.3 %; p=0.98) were unaltered. Pearson’s correlations demonstrated that fire attack completion time was inversely associated with changes in cf-PWV (r=-0.53, p=0.01) but not AIx (r=-0.13, p=0.56). CONCLUSIONS: No changes in central or peripheral indices of arterial stiffness were observed following a short-duration, high-intensity simulated fire attack in male career firefighters. The observed association between fitness, indexed as fire attack completion time, and changes in cf-PWV may be explained by intensity-dependent arterial stiffness responses, whereby increases in arterial stiffness in fitter firefighters may be attributed to an ability to perform the task at a greater relative intensity

ACUTE TRUNK STRETCHING EFFECTS ON CENTRAL AND PERIPHERAL BLOOD PRESSURE IN MIDDLE-AGED TO OLDER ADULTS

Kaelyn Spears1, Kylee West2,,1, Gregory J. Grosicki1, Barry Joyner2, Collin Smith3, Nick J. Siekirk2. 1Georgia Southern University (Armstrong), Savannah, GA. 2Georgia Southern University, Statesboro, GA. 3East Georgia Regional Hospital, Statesboro, GA. BACKGROUND: Approximately 75% of Americans ≥60 years have hypertension, which is the leading modifiable risk factor for cardiovascular disease and all-cause mortality. Chronic aerobic exercise reduces blood pressure (BP), and even a single bout of aerobic exercise can yield a sustained reduction in BP (i.e., postexercise hypotension). There is mounting evidence that chronic stretching may also reduce BP, but whether a single bout of stretching can acutely lower BP, as is seen with aerobic exercise, is less clear. Therefore, the purpose of this study was to examine the effects of acute trunk stretching using an exercise ball on central and peripheral BP in middle-aged to older adults. METHODS: We measured central and peripheral BP using a SphgymoCor XCEL device in 13 middle-aged to older adults (6M/7F; 70 ± 9 yrs; 31.1 ± 4.4 kg/m2; Means ± SD) before and 10-min after partner-assisted passive trunk stretching and a time-matched control visit, the order of which was randomized. The passive stretching visit consisted of six trunk stretches (flexion, extension, and bi-directional lateral flexion and standing rotation). For each participant, the first stretch was randomized. Each stretch was held for 30 seconds, followed by 30 seconds of relaxation, and this sequence was repeated 5 times in rotational order for a total of 30 minutes. The time-matched control visit consisted of 30 minutes of quiet seated upright rest. Visits were separated by a minimum of 48 hours (average separation = 7 ± 9 days). A repeated measures linear mixed model was used to compare changes (Δ; post - pre) in BP between visits. RESULTS: Average resting central BP was 120 ± 9 / 76 ± 10 mmHg and brachial BP was 128 ± 10 / 75 ± 9 mmHg during the two visits. Changes in brachial systolic (stretch: -4 ± 7 mmHg vs. control: 6 ± 6 mmHg; p = 0.002) and diastolic (stretch: -3 ± 4 mmHg vs. control: 2 ± 4 mmHg; p = 0.009) BP, as well as central systolic (stretch: -4 ± 6 mmHg vs. control: 6 ± 6 mmHg; p \u3c 0.001) and diastolic (stretch: -3 ± 6 mmHg vs. control: 3 ± 5 mmHg; p = 0.014) BP measurements differed between visits. CONCLUSION: These preliminary findings indicate that acute passive assisted trunk stretching with an exercise ball reduces central and peripheral blood pressure in middle-aged to older adults

ACUTE EFFECTS OF TRUNK STRETCHING ON AORTIC ARTERIAL STIFFNESS IN MIDDLE-AGED TO OLDER ADULTS

Kylee West1,,2, Gregory J. Grosicki2, Kaelyn Spears2, Barry Joyner3, Collin Smith4, Nick J. Siekirk1,3. 1Biomechanics Lab, Georgia Southern University, Statesboro, GA. 2Biodynamics and Human Performance Center, Georgia Southern University (Armstrong), Savannah, GA. 3Center for Rehabilitation and Independent Living, Waters College of Health Professions, Statesboro, GA. 4Internal Medicine, East Georgia Regional Hospital, Savannah, GA. BACKGROUND: Aortic arterial stiffness increases with age and is associated with elevated risk for cardiovascular morbidity and mortality. Physical activity may alter the trajectory of age-related arterial stiffening. In young males, it has been demonstrated that acute trunk stretching reduces arterial stiffness and increases carotid arterial compliance, but whether such benefits translate to middle-aged to older males and females is less clear. Therefore, the purpose of this study was to examine the effects of acute trunk stretching using an exercise ball on aortic arterial stiffness and arterial wave reflections in middle-aged to older adults. METHODS: We measured carotid-femoral pulse wave velocity (cf-PWV; an index of aortic arterial stiffness) and augmentation index normalized to a heart rate of 75 beats per minute (AIx75; an index of arterial wave reflection and myocardial burden) in 13 middle-aged to older adults (6M/7F; 70 ± 9 yrs; 31.1 ± 4.4 kg/m2; Means ± SD) before and 10-min after partner-assisted passive trunk stretching and a time-matched control visit, the order of which was randomized. The passive stretching visit consisted of six trunk stretches (flexion, extension, and bi-directional lateral flexion and standing rotation). For each participant, the first stretch was randomized. Each stretch was held for 30 seconds, followed by 30 seconds of relaxation, and this sequence was repeated 5 times in rotational order for a total of 30 minutes. The time-matched control visit consisted of 30 minutes of quiet seated upright rest. Visits were separated by a minimum of 48 hours (average separation = 7 ± 9 days). A repeated measures linear mixed model was used to compare changes (Δ; post - pre) in cf-PWV and AIx75 between visits. RESULTS: Average resting cf-PWV during the two visits was 9.01 ± 1.4 m/s and AIx75 was 34.8 ± 7.6 %. Changes in cf-PWV were similar between trunk stretching (-0.09 ± 0.64 m/s) and control (0.23 ± 0.62 m/s) visits, without adjustment for mean arterial pressure (p = 0.218) and with adjustment (p = 0.969). Likewise, changes in AIx75 were similar (p = 0.151) between trunk stretching (0.50 ± 4.20 %) and control visits (-2.42 ± 5.72 %). CONCLUSION: These preliminary findings indicate that acute trunk stretching using an exercise ball does not alter aortic arterial stiffness or arterial wave reflections in middle-aged to older adults

INFLUENCE OF DIETARY SODIUM AND FIBER ON BLOOD PRESSURE AND VASCULAR FUNCTION IN YOUNG ADULTS

Zach J. Hutchison1, Braxton A. Linder1, McKenna A. Tharpe1, Alex M. Barnett1, Meral N. Culver1, Sofia O. Sanchez1, Soolim Jeong1, Joseph C. Watso2, Gregory J. Grosicki3, Austin T. Robinson1. 1Auburn University, Auburn, AL. 2Florida State University, Tallahassee, FL. 3Georgia Southern University, Savannah, GA. Background: High dietary sodium (Na+) increases blood pressure (BP) and decreases vascular function, whereas high dietary fiber is associated with reduced BP. However, the combined effect of dietary Na+ and fiber on BP and vascular function is unclear. Therefore, we assessed dietary Na+ indexed to fiber (Na+/Fiber) and soluble fiber (Na+/Sol Fiber) intake in healthy young adults. Methods: Forty-six young adults (24 Male/22 Female, 21.0 ± 0.7 years, body mass index: 25 ± 3 kg/m2, BP 117 ± 9/69 ± 9 mmHg, mean ± SD) were included in this analysis. We assessed brachial BP and carotid-femoral pulse wave velocity (cf-PWV; an index of arterial stiffness) using SphygmoCor XCEL. In a subset of 40 participants, we assessed brachial artery flow-mediated dilation (FMD; Arietta 70 vascular ultrasound). Participants completed a food and fluid log for ≥2 weekdays and ≥1 weekend day. We used Nutrition Data System for Research to quantify average daily dietary Na+, total fiber, and soluble fiber. We analyzed the association between variables using simple linear regression and ANOVA (to compare tertiles of Na+/Fiber or Na+/Sol Fiber). Results: There was not an association between BP and Na+/Fiber (systolic BP: R2 = 0.046, p = 0.150, diastolic BP: R2 = 0.061, p = 0.097), but there was between BP and Na+/Sol Fiber (systolic BP: R2 = 0.080, p = 0.056, diastolic BP: R2 = 0.113, p = 0.022). When participants were split into tertiles by Na+/Fiber and Na+/Sol Fiber, we detected differences in diastolic BP (ps \u3c 0.043) but not systolic BP (ps ≥ 0.097). Participants’ cf-PWV was associated with Na+/Fiber (R2 = 0.152, p = 0.001) and Na+/Sol Fiber (R2 = 0.116, p = 0.007), but we did not detect tertile differences in cf-PWV for either Na+/Fiber or Na+/Sol Fiber (ps ≥ 0.128). Neither Na+/Fiber nor Na+/Sol Fiber were associated with FMD and there were no differences in FMD among tertile groups (ps ≥ 0.149). Conclusion: While additional data are needed, our data in healthy young adults indicate that dietary sodium indexed to soluble fiber is associated with increased blood pressure and arterial stiffness but is not related to peripheral vascular endothelial function

INFLUENCE OF DIETARY SODIUM AND FIBER ON AMBULATORY BLOOD PRESSURE IN HEALTHY YOUNG ADULTS

Soolim Jeong1, Joseph D. Vondrasek2, Braxton A. Linder1, Zach J. Hutchison1, Jordan E. Kinnel3, Meral N. Culver1, McKenna A. Tharpe1, Sofia O. Sanchez1, Joseph C. Watso4, Gregory J. Grosicki2, Austin T. Robinson1. 1Auburn University, Auburn, AL. 2Georgia Southern University, Savannah, GA. 3Tuskegee University, Tuskegee, AL. 4Florida State University, Tallahassee, FL. BACKGROUND: Dietary sodium (Na+) elevates blood pressure (BP) and blunts nocturnal BP dipping, which is prognostic of future target organ damage and cardiovascular outcomes. Dietary fiber is associated with reduced resting BP. However, the combined effects of dietary Na+ and fiber on ambulatory BP measures, such as nocturnal BP and night-to-day dip ratio (nighttime/daytime BP), are unclear. Therefore, we assessed associations between dietary Na+ indexed to fiber (Na+/fiber) and soluble fiber (Na+/soluble fiber) on ambulatory BP in young adults. METHODS: Sixty-two participants (30 M/32 F, 39 White adults/23 Black adults, age 21.2 ± 2.6 years, BMI 24 ± 3 kg/m2; mean ± SD) were included in the current analysis. Participants completed a food and fluid log for ≥ two weekdays and ≥ one weekend day. We used Nutrition Data System for Research to quantify average daily Na+, fiber, and soluble fiber intake. For ambulatory BP (Suntech Oscar2), participants wore a brachial cuff programmed to measure BP every 20 minutes during awake hours and every 30 minutes during sleep. Primary BP outcomes were average awake and asleep systolic BP (SBP) and diastolic BP (DBP), and night-to-day SBP and DBP dip ratio. Associations between variables were made using Spearman’s Rho (ρ) correlations controlled for sex, BMI, and race with α set at ≤ 0.05. RESULTS: When controlling for sex and BMI, dietary Na+ was correlated with awake SBP (ρ = 0.36, p = 0.005) and asleep SBP (ρ = 0.26, p = 0.044) but not BP dipping ratios (ps ≥ 0.542). Dietary Na+/fiber was also correlated with asleep SBP (ρ = 0.26, p = 0.046) and DBP (ρ = 0.25, p = 0.050) but not BP dipping ratios (ps ≥ 0.243). Dietary Na+/soluble fiber was correlated with SBP dip ratio (ρ = 0.27, p = 0.036) and asleep SBP (ρ = 0.32, p = 0.012). When controlling for race, in addition to sex and BMI, dietary Na+ remained correlated to awake SBP (ρ = 0.36, p = 0.005) and asleep SBP (ρ = 0.29, p = 0.028). Dietary Na+/soluble fiber remained correlated with asleep SBP (ρ = 0.28, p = 0.030). However, controlling for race attenuated the associations between Na+/fiber on asleep BP and Na+/soluble fiber on BP dipping (ps ≥ 0.130). CONCLUSIONS: Our cross-sectional data in healthy young adults indicate that dietary sodium indexed to soluble fiber is independently associated with elevated nocturnal blood pressure

THE INFLUENCE OF BEETROOT JUICE ON RACIAL DISPARITIES IN VASCULAR HEALTH

James E. Brown1, Brett L. Cross1, Joseph D. Vondrasek1, Josiah M. Frederick1, Zoe R. Lincoln1, Peter Gaither1, Wesley T. Blumenburg1, Amy Chall1, Anna Bryan1, Ana Palacios1, Andrew A. Flatt1, Austin T. Robinson2, Gregory J. Grosicki1. 1Georgia Southern University (Armstrong Campus), Savannah, GA. 2Auburn University, Auburn, AL. BACKGROUND: In America, Black adults are 30% more likely to die from cardiovascular disease than White adults. More than half of this racial health disparity can be attributed to greater prevalence of high blood pressure (BP) and vascular dysfunction in Black adults. Nitric oxide (NO) is a potent signaling molecule, key regulator of vascular health, and NO bioavailability is suspected to be lower in Black individuals. Therefore, we tested the hypothesis that increasing NO bioavailability via nitrate-rich beetroot juice (BRJ) would attenuate racial differences in BP and vascular health in Black compared to White adults. METHODS: We recruited 18 Black (10M/8F; 21±3 years; 24±3 kg/m2) and 20 White (10M/10F; 21±4 years; 23±3 kg/m2) young adults for a randomized, placebo-controlled, acute BRJ study. Central and peripheral BP and carotid-femoral pulse wave velocity (cf-PWV; an index of central arterial stiffness) were measured before and two hours after ingesting nitrate-rich BRJ (~12.8 mmol) and nitrate-deplete BRJ placebo (PLA), given in random order. Baseline cardiovascular measures were compared between visits (paired) and races (independent) t-tests. Post-supplementation cardiovascular measures were compared between races (i.e., Black vs. White) and treatment (i.e., BRJ vs. PLA) using linear mixed models. RESULTS: Compared to White participants, Black participants demonstrated greater baseline brachial diastolic (66±7 vs. 71±6mmHg; P=0.009), central systolic (100±8 vs. 107±10mmHg; P=0.028), and central diastolic BP (67±6 vs. 72±6mmHg; P=0.014). Brachial systolic BP (115±8 vs. 121±10mmHg; P=0.051) and cf-PWV (5.7±0.8 vs. 6.1±0.8m/s; P=0.075) were not statistically different in White vs. Black participants. Baseline BP and cf-PWV values were not different between BRJ and PLA visits (P≥0.288). Compared to PLA, post-BRJ supplementation brachial (-3.8mmHg; 95%CI: -6.6 to -1.1) and central systolic BP (-2.8mmHg; 95%CI: -5.1 to -0.5) were lower, but not other treatment effects were observed (P≥0.301). Significant main effects for race (P≤0.020) indicated that baseline differences in BP (i.e., higher in Black vs. White) remained post-supplementation. CONCLUSION: These data suggest that an acute nitrate-rich BRJ supplement lowers central and peripheral BP in young Black and White adults. However, acute BRJ supplementation does not appear to influence cf-PWV or attenuate racial differences in vascular health indices