Acute beetroot juice reduces blood pressure in young Black and White males but not females.

A complex interplay of social, lifestyle, and physiological factors contribute to Black Americans having the highest blood pressure (BP) in America. One potential contributor to Black adult's higher BP may be reduced nitric oxide (NO) bioavailability. Therefore, we sought to determine whether augmenting NO bioavailability with acute beetroot juice (BRJ) supplementation would reduce resting BP and cardiovascular reactivity in Black and White adults, but to a greater extent in Black adults. A total of 18 Black and 20 White (∼equal split by biological sex) young adults completed this randomized, placebo-controlled (nitrate (NO3-)-depleted BRJ), crossover design study. We measured heart rate, brachial and central BP, and arterial stiffness (via pulse wave velocity) at rest, during handgrip exercise, and during post-exercise circulatory occlusion. Compared with White adults, Black adults exhibited higher pre-supplementation resting brachial and central BP (Ps ≤0.035; e.g., brachial systolic BP: 116(11) vs. 121(7) mmHg, P = 0.023). Compared with placebo, BRJ (∼12.8 mmol NO3-) reduced resting brachial systolic BP similarly in Black (Δ-4±10 mmHg) and White (Δ-4±7 mmHg) adults (P = 0.029). However, BRJ supplementation reduced BP in males (Ps ≤ 0.020) but not females (Ps ≥ 0.299). Irrespective of race or sex, increases in plasma NO3- were associated with reduced brachial systolic BP (ρ = -0.237, P = 0.042). No other treatment effects were observed for BP or arterial stiffness at rest or during physical stress (i.e., reactivity); Ps ≥ 0.075. Despite young Black adults having higher resting BP, acute BRJ supplementation reduced systolic BP in young Black and White adults by a similar magnitude, an effect that was driven by males.

Habituation attenuates the sex-specific associations between ischemic pain, blood pressure, and arterial stiffness in young adults.

Cardiovascular reactivity (CVR) during physical stress is prognostic for incident cardiovascular disease. CVR is influenced by perceived pain. However, there is limited data on the effect of sex differences and repeated exposures to painful stimuli on CVR. We measured blood pressure (BP) and carotid-femoral pulse wave velocity (cf-PWV; an index of arterial stiffness) at rest, during isometric handgrip (HG) exercise at 30% of maximum voluntary contraction, and during postexercise circulatory occlusion (PECO) during two identical trials in 39 adults (20M/19F; 18-39 yr). We assessed participants' perceived pain using a visual analog scale after the first minute of each stimulus. We collected BP during minute 2 of each stimulus and cf-PWV during minute 3 of each stimulus. In male participants, we observed moderate associations (Ps ≤ 0.023) between perceived pain and changes in brachial diastolic (ρ = 0.620) and mean BP (ρ = 0.597); central diastolic, mean, and systolic BP (ρs = 0.519-0.654); and cf-PWV (ρ = 0.680) during PECO in trial 1, but not trial 2 (Ps ≥ 0.162). However, in female participants, there were no associations between pain and CVR indices during either trial (Ps ≥ 0.137). Irrespective of sex, reductions in perceived pain during trial 2 relative to trial 1 were weakly to moderately associated (Ps ≤ 0.038) with reductions in brachial diastolic (ρ = 0.346), mean (ρ = 0.379), and systolic BP (ρ = 0.333); central mean (ρ = 0.400) and systolic BP (ρ = 0.369); and cf-PWV (ρ = 0.526). These findings suggest that 1) there are sex differences in pain modulation of CVR in young adults and 2) habituation blunts pain and CVR during PECO, irrespective of sex.NEW & NOTEWORTHY We demonstrate sex differences in the association between pain perception and cardiovascular reactivity (CVR) during ischemic pain. We also demonstrate habituation to pain and reduced CVR during repeated exposure in a sex-independent manner. Accounting for sex differences and habituation may improve the prognostic utility of CVR.

Cardiorespiratory Fitness Is Inversely Associated With Aortic Arterial Stiffness in Firefighters.

OBJECTIVES: The aim of this study was to determine whether cardiorespiratory fitness (CRF), expressed as VO 2 max (mL/kg/min), is associated with resting AS (carotid-femoral pulse wave velocity [cf-PWV]) and the AS response to simulated fire suppression activities in firefighters. METHODS: In firefighters (n = 20, 34 ± 8 years), AS was determined using cf-PWV (m/s) before and after a fire simulation exercise. VO 2 max was determined using a standard treadmill protocol. Linear regression models, adjusted for body fat percentage, are reported as unstandardized (b) and standardized (ß) betas (effect sizes). RESULTS: H1: there was a moderate (ie, ß = 0.5-0.8), inverse association between cf-PWV and VO 2 max (b = -0.80; 95% confidence interval [CI], -0.14 to -0.02; ß = 0.71). H2: there was a moderate, positive association between ∆cf-PWV and VO 2 max (b = 0.05; 95% CI, 0.00-0.10; ß = 0.62). CONCLUSIONS: These findings indicate that CRF may protect against arterial stiffening in firefighters.

Physical fitness, but not physical activity, is associated with mental health in apparently healthy young adults.

BACKGROUND: The prevalence of mental health disorders is rising globally. Despite the popularity of exercise as a strategy to improve mental health in individuals with anxiety or depression, there is a paucity of literature on this topic in apparently healthy young individuals who are free from mental illness. METHODS: We characterized relationships between actigraphy-derived physical activity levels and cardiorespiratory fitness (V̇O2max; via maximal graded exercise testing), with mental health assessed using psychometric questionnaires (POMS and PSS) in apparently healthy young adults (26±4.3yrs; 22 women and 26 men). RESULTS: In women and men combined, relative V̇O2max (33.5±8.1 mL/kg/min) was associated (P<0.01) with POMS (r=-0.454) and PSS (r=-0.510) scores, and relationships between fitness and POMS were preserved (P<0.05) after controlling for body fat (27.2±9.9%). Additionally, V̇O2max was associated (P<0.05) with numerous POMS subcomponents (tension, anger, fatigue, depression, confusion; all P<0.05). No relationships (P>0.05) were observed between physical activity profiles (sedentary time, light intensity time, moderate-vigorous intensity time, total steps, counts per day) with POMS or PSS scores, and only total steps was associated with relative V̇O2max (r=0.331; P=0.021). Relationships between relative V̇O2max and POMS scores were also observed in men (r=-0.407, P=0.039) and women (r=-0.490; P=0.021) individually, but V̇O2max and PSS relationships were exclusive to men (r=-0.516, P=0.007). CONCLUSIONS: Independent of body composition, cardiorespiratory fitness, but not actigraphy-derived physical activity, is associated with mental health in apparently healthy young men and women. To maximize mental health benefits, exercise training interventions are advised to focus on eliciting improvements in cardiorespiratory fitness.