Interplay of Race and Neighborhood Deprivation on Resting and Ambulatory Blood Pressure in Young Adults.

BACKGROUND: Nighttime BP and BP dipping (daytime-nighttime BP) are prognostic for cardiovascular disease. Compared with other racial/ethnic groups, Black Americans exhibit elevated nighttime BP and attenuated BP dipping. Neighborhood deprivation may contribute to disparities in cardiovascular health, but its effects on resting and ambulatory BP patterns in young adults is unclear. Therefore, we examined associations between neighborhood deprivation with resting and nighttime BP and BP dipping in young Black and White adults. METHODS: We recruited 19 Black and 28 White participants (23 M/24 F, 21±1 years, body mass index: 26±4 kg/m2) for 24-hour ambulatory BP monitoring. We assessed resting BP, nighttime BP, and BP dipping (absolute dip and nighttime:daytime BP ratio). We used the area deprivation index (ADI) to assess average neighborhood deprivation during early- and mid-childhood, and adolescence. RESULTS: Compared with White participants, Black participants exhibited higher resting systolic and diastolic BP (ps≤0.029), nighttime systolic BP (114±9 vs. 108±9 mmHg, p=0.049), diastolic BP (63±8 vs. 57±7 mmHg, p=0.010), and attenuated absolute systolic BP dipping (12±5 vs. 9±7 mmHg, p=0.050). Black participants experienced greater average ADI scores compared with White participants (110(10) vs. 97(22), p=0.002), and select ADI scores correlated with resting BP and some ambulatory BP measures. Within each race, select ADI scores correlated with some BP measures for Black participants, but there were no ADI and BP correlations for White participants. CONCLUSIONS: Our findings suggest neighborhood deprivation may contribute to higher resting BP and impaired ambulatory BP patterns in young adults warranting further investigation in larger cohorts.

Adjusting for muscle strength and body size attenuates sex differences in the exercise pressor reflex in young adults.

Females typically exhibit lower blood pressure (BP) during exercise than males. However, recent findings indicate that adjusting for maximal strength attenuates sex differences in BP during isometric handgrip (HG) exercise and postexercise ischemia (PEI; metaboreflex isolation). In addition, body size is associated with HG strength but its contribution to sex differences in exercising BP is less appreciated. Therefore, the purpose of this study was to determine whether adjusting for strength and body size would attenuate sex differences in BP during HG and PEI. We obtained beat-to-beat BP in 110 participants (36 females, 74 males) who completed 2 min of isometric HG exercise at 40% of their maximal voluntary contraction followed by 3 min of PEI. In a subset (11 females, 17 males), we collected muscle sympathetic nerve activity (MSNA). Statistical analyses included independent t tests and mixed models (sex × time) with covariate adjustment for 40% HG force, height2, and body surface area. Females exhibited a lower absolute 40% HG force than male participants (Ps < 0.001). Females exhibited lower Δsystolic, Δdiastolic, and Δmean BPs during HG and PEI than males (e.g., PEI, Δsystolic BP, 15 ± 11 vs. 23 ± 14 mmHg; P = 0.004). After covariate adjustment, sex differences in BP responses were attenuated. There were no sex differences in MSNA. In a smaller strength-matched cohort, there was no sex × time interactions for BP responses (e.g., PEI systolic BP, P = 0.539; diastolic BP, P = 0.758). Our data indicate that sex differences in exercising BP responses are attenuated after adjusting for muscle strength and body size.NEW & NOTEWORTHY When compared with young males, females typically exhibit lower blood pressure (BP) during exercise. Adjusting for maximal strength attenuates sex differences in BP during isometric handgrip (HG) exercise and postexercise ischemia (PEI), but the contribution of body size is unknown. Novel findings include adjustments for muscle strength and body size attenuate sex differences in BP reactivity during exercise and PEI, and sex differences in body size contribute to HG strength differences.

Interplay of Race and Neighborhood Deprivation on Ambulatory Blood Pressure in Young Adults.

Background: Ambulatory blood pressure (BP) monitoring measures nighttime BP and BP dipping, which are superior to in-clinic BP for predicting cardiovascular disease (CVD), the leading cause of death in America. Compared with other racial/ethnic groups, Black Americans exhibit elevated nighttime BP and attenuated BP dipping, including in young adulthood. Social determinants of health contribute to disparities in CVD risk, but the contribution of neighborhood deprivation on nighttime BP is unclear. Therefore, we examined associations between neighborhood deprivation with nighttime BP and BP dipping in young Black and White adults. Methods: We recruited 21 Black and 26 White participants (20 M/27 F, mean age: 21 years, body mass index: 25±4 kg/m2) for 24-hour ambulatory BP monitoring. We assessed nighttime BP and BP dipping (nighttime:daytime BP ratio). The area deprivation index (ADI) was used to measure neighborhood deprivation. Associations between ADI and ambulatory BP were examined. Results: Black participants exhibited higher nighttime diastolic BP compared with White participants (63±8 mmHg vs 58±7 mmHg, p=0.003), and attenuated BP dipping ratios for both systolic (0.92±0.06 vs 0.86±0.05, p=0.001) and diastolic BP (0.86±0.09 vs 0.78±0.08, p=0.007). Black participants experienced greater neighborhood deprivation compared with White participants (ADI scores: 110±8 vs 97±21, p<0.001), and ADI was associated with attenuated systolic BP dipping (ρ=0.342, p=0.019). Conclusions: Our findings suggest neighborhood deprivation may contribute to higher nighttime BP and attenuated BP dipping, which are prognostic of CVD, and more prevalent in Black adults. Targeted interventions to mitigate the effects of neighborhood deprivation may help to improve nighttime BP. Clinical Trial Registry: URL: https://www.clinicaltrials.gov; Unique identifier: NCT04576338.

Fan Cooling Improves Submaximal Exercise Capacity in an Indoor Thermoneutral Environment.

Purpose: We compared physiological and perceptual responses to submaximal, moderate-vigorous, heart rate-based cycle ergometry with and without a fan. Methods: Sixteen recreationally active adults (25 ± 3 years; 8 men and 8 women) participated in the study. After an initial visit to assess cardiorespiratory fitness, each participant performed two 40-min training sessions on a cycle ergometer, either with or without a fan (~4 m/s), while workload was continually adjusted to elicit and maintain 70% of heart rate reserve. Workload, oxygen cost, and respiratory exchange ratio were monitored throughout, and rating of perceived exertion (RPE) and thermal sensation were recorded every 5 min. Blood lactate was recorded pre-, mid-, and post-sessions and nude body mass was obtained pre-post. Results: Greater (p < .01) mean workload (+15%) and oxygen consumption (+9%) yielded significantly greater (p < .01) energy expenditure with fan cooling (344 ± 124 kcals) compared to without fan cooling (302 ± 103 kcals). Thermal sensation, but not RPE (p = .09), was lower (p < .01) with fan cooling (3.8 ± 0.7) compared to without fan cooling (5.5 ± 0.8), and body mass loss was attenuated (p < .05) with fan cooling (-0.4 ± 0.2 kg) compared to the non-fan trial (-0.6 ± 0.3 kg). Significantly higher (p < .05) blood lactate values were observed in Fan (3.0 ± 1.9 mmol/l) vs. No Fan (2.5 ± 1.4 mmol/l) trials. Conclusions: Fan cooling during submaximal, moderate-vigorous intensity cycle ergometry significantly enhanced work capacity and energy expenditure without increasing perceived exertion. These data highlight the utility of fan cooling as a means to increase the effectiveness of indoor, heart rate-based cycle training.

Self-recorded heart rate variability profiles are associated with health and lifestyle markers in young adults.

PURPOSE: To quantify associations between self-recorded heart rate variability (HRV) profiles and various health and lifestyle markers in young adults. METHODS: Otherwise healthy volunteers (n = 40, 50% male) recorded 60-s, post-waking HRV with a cost-free mobile application in supine and standing positions for 7 days. The 7-day average and coefficient of variation (CV, reflects daily fluctuation) for the mean RR interval and root mean square of successive differences (LnRMSSD) were assessed. 7-day sleep duration and physical activity profiles were characterized via wrist-worn accelerometer. Subsequent laboratory assessments included aerobic fitness ([Formula: see text]O2peak) and markers of cardiovascular, metabolic, and psychoemotional health. Associations were evaluated before and after [Formula: see text]O2peak adjustment. RESULTS: Bivariate correlations (P < 0.05) demonstrated that higher 7-day averages and/or lower CV values were associated with higher activity levels and superior cardiovascular (lower systolic and diastolic blood pressure [BP] and aortic stiffness [cf-PWV]), metabolic (lower body fat percentage, fasting glucose, and low-density lipoprotein cholesterol [LDL-C]), and psychoemotional health (lower perceived stress) markers, with some variation between sexes and recording position. In males, associations between HRV parameters and cf-PWV remained significant following [Formula: see text]O2peak adjustment (P < 0.05). In females, HRV parameters were associated (P < 0.05) with numerous cardiovascular (systolic and diastolic BP, cf-PWV) and metabolic (fasting glucose and LDL-C) parameters following [Formula: see text]O2peak adjustment. CONCLUSIONS: Higher or more stable supine and standing HRV were generally associated with superior health and lifestyle markers in males and females. These findings lay groundwork for future investigation into the usefulness of self-recorded ultra-short HRV as a health-promoting behavior-modification tool in young adults.

Sleep duration irregularity is associated with elevated blood pressure in young adults.

Sleep irregularity (i.e., highly variable sleep patterns) is an emerging risk factor for cardiometabolic disease. Though irregular sleep patterns are common among young adults, the cardiometabolic health (CMH) repercussions of sleep irregularity in this population are unclear. We examined associations between sleep duration and irregularity with measures of CMH in 44 (24 M/20 F, 23 ± 5y, BMI 26 ± 4 kg/m2, blood pressure (BP): 125/71 ± 14/9 mmHg) young adults. Participants wore actigraphy monitors for seven-days and sleep duration irregularity was operationalized as the standard deviation of nightly sleep duration (sleep SD). CMH variables of interest included brachial and aortic BP, arterial stiffness (cf-PWV), augmentation index (AIx75), and fasting blood glucose and lipids. Associations between sleep duration and sleep SD with CMH variables were assessed via correlations adjusted for sex and BMI. Sleep duration generally was not associated with CMH indices. However, sleep SD was associated with brachial systolic (r = 0.433, p = .027) and diastolic BP (r = 0.415, p = .035). Similarly, sleep duration SD was associated with aortic systolic BP (r = 0.447, p = .022). Our findings show that sleep irregularity, but not duration, is associated with higher brachial and central BP in young adults.Abbreviations: AIx75: augmentation index at a heart rate of 75 beats per minute; BP: blood pressure; CMH: cardiometabolic health; cf-PWV: carotid-femoral pulse wave velocity; DXA: dual x-ray absorptiometry; mg/dl: milligrams per deciliter; PWA: pulse wave analysis; PWV: pulse wave velocity; sleep duration SD: standard deviation of nightly sleep duration.

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.

Self-reported sleep quality is associated with central hemodynamics in healthy individuals.

BACKGROUND: Insufficient sleep is associated with arterial stiffness and elevated cardiovascular disease risk. Central hemodynamics are influenced by arterial stiffness, yet independently predict cardiovascular risk. Relationships between sleep characteristics and central hemodynamic parameters are largely unexplored. We aimed to characterize the relationship between self-reported sleep quality and central hemodynamics in healthy individuals. To explore the secondary hypothesis that impairments in glucose metabolism may underlie relationships between sleep and central hemodynamic variables, we also explored associations between self-reported sleep quality and fasting blood glucose values. METHODS: Thirty-one healthy study subjects (20 to 69 years, 17 men) were free from metabolic or cardiovascular disease and did not take sleep medication. Self-reported sleep quality was obtained using the Pittsburgh Sleep Quality Index (PSQI) with normal sleepers defined by PSQI scores 0-5 and poor sleepers by PSQI score > 5. Relationships were assessed between PSQI, central hemodynamic profiles (systolic and diastolic blood pressures, pulse and augmentation pressures, augmentation index) estimated from oscillometric pulse wave analysis, and blood glucose values. RESULTS: Central pulse pressure was significantly elevated in poor (PSQI score > 5) compared with that in normal (PSQI scores 0-5) sleepers (P < 0.05). Linear regression models, adjusted for age, gender, and body mass index, demonstrated PSQI score to be an independent predictor (P < 0.05) of both central pulse (ß = 0.469) and augmentation (ß = 0.364) pressures. Global PSQI scores were not related to fasting blood glucose values (r = 0.045; P > 0.05). CONCLUSIONS: Significant relationships between central pulse and augmentation pressures and self-reported sleep quality highlight the importance of considering sleep when examining lifestyle contributors to central hemodynamics.