Hypertension at the nexus of veteran status, psychiatric disorders, and traumatic brain injury: Insights from the 2011 Behavioral Risk Factor Surveillance System.

Variable military service-related experiences, such as combat exposure, psychiatric disorders (PD), and traumatic brain injuries (TBI), may differentially affect the likelihood of having health care professional-identified high blood pressure (i.e., hypertension). PURPOSE: Compare the odds of self-reported hypertension among non-combat and combat veterans with and without PD/TBI to non-veterans and each other. METHODS: We used data from men from the 2011 Behavioral Risk Factor Surveillance System and distinguished: non-veterans (n = 21,076); non-combat veterans with no PD/TBI (n = 3,150); combat veterans with no PD/TBI (n = 1,979); and veterans (combat and non-combat) with PD and/or TBI (n = 805). Multivariable, hierarchical logistic regression models included exogenous demographic, socioeconomic attainment and family structure, health behavior and conditions, and methodological control variables. RESULTS: One-third of men reported having been told at least once by a medical professional that they had high blood pressure. Bivariate analyses indicated that each veteran group had a higher prevalence of self-reported hypertension than non-veterans (design-based F = 45.2, p<0.001). In the fully adjusted model, no statistically significant differences in the odds of self-reported hypertension were observed between non-veterans and: non-combat veterans without PD/TBI (odds ratio [OR] = 0.92); combat veterans without PD/TBI (OR = 0.87); veterans with PD and/or TBI (OR = 1.35). However, veterans with PD and/or TBI had greater odds of reporting hypertension than both combat and non-combat veterans without PD/TBI (p<0.05). DISCUSSION: Military service-related experiences were differentially associated with a survey-based measure of hypertension. Specifically, veterans self-reporting PD and/or TBI had significantly higher odds of self-reporting hypertension (i.e., medical provider-identified high blood pressure).

Central hemodynamic response to activation of the vestibular sympathetic reflex with head-down rotation in healthy young adults.

The purpose of this study was to assess the effect of vestibular sympathetic activation on estimated measures of central (aortic) hemodynamic load in young adults. Thirty-one participants (n = 14 females and 17 males) underwent cardiovascular measures in the prone position with the head in a neutral position and during 10 min of head-down rotation (HDR), as a means of activating the vestibular sympathetic reflex. Radial pressure waveforms were acquired via applanation tonometry and, with the use of a generalized transfer function, used to synthesize an aortic pressure waveform. Popliteal vascular conductance was derived from diameter and flow velocity measured via Doppler-ultrasound. Subjective orthostatic intolerance was assessed using a 10-item orthostatic hypotension questionnaire. There was a reduction in brachial systolic blood pressure (BP) during HDR (111 ± 10 vs. 109 ± 9 mmHg, P < 0.05), but there was no change in aortic systolic BP (100 ± 9 vs. 99 ± 8 mmHg, P > 0.05). Aortic augmentation index (-5 ± 11 vs. -12 ± 12%, P < 0.05) and reservoir pressure (28 ± 8 vs. 26 ± 8 mmHg, P < 0.05) were reduced with a concomitant reduction in popliteal conductance (5.6 ± 0.7 vs. 4.5 ± 0.7 mL/min·mmHg, P < 0.05). Change in aortic systolic BP was associated with subjective orthostatic intolerance score (r = -0.39, P < 0.05). Activation of the vestibular sympathetic reflex via HDR resulted in slight reductions in brachial BP concomitant with preservation of aortic BP. Despite peripheral vascular constriction during HDR, there was a reduction in pressure from wave reflections and reservoir pressure. Finally, there was an association between change in aortic systolic BP during HDR and orthostatic intolerance score, suggesting that individuals who cannot defend against drops in aortic BP during vestibular sympathetic reflex activation may be more likely to experience higher subjective symptomatology of orthostatic intolerance.NEW & NOTEWORTHY Despite peripheral vasoconstriction, activation of the vestibular-sympathetic reflex results in a reduction in cardiac workload. Reduction in cardiac workload is likely due to reductions in pressure from wave reflections and reservoir pressure.

Arterial stiffness and augmentation index are associated with balance function in young adults.

OBJECTIVE: Arterial stiffness and pulsatile central hemodynamics have been shown to affect various aspects of physical function, such as exercise capacity, gait speed, and motor control. The aim of this study was to examine the potential association between arterial stiffness and balance function in healthy younger men and women. METHODS: 112 participants (age = 21 ± 4 years, n = 78 women) underwent measures of arterial stiffness, pulsatile central hemodynamics, balance function and physical fitness in this cross-sectional study. Postural sway was measured in triplicate while participants stood on a foam surface with their eyes closed for 20 s. The average total center of pressure path length from the three trials was used for analysis. Measures of vascular function were estimated using an oscillometric blood pressure device while at rest and included pulse wave velocity (PWV), augmentation index (AIx), and pulse pressure amplification. Measures of physical fitness used as covariates in statistical models included handgrip strength determined from a handgrip dynamometer, lower-body flexibility assessed using a sit-and-reach test, estimated maximal aerobic capacity (VO2max) using heart rate and a step test, and body fat percentage measured from air displacement plethysmography. RESULTS: The results from linear regression indicated that after considering sex, mean arterial pressure, body fat, estimated VO2max, handgrip strength, and sit-and-reach, PWV (ß = 0.44, p < 0.05) and AIx (ß = - 0.25, p < 0.01) were significant predictors of postural sway, explaining 10.2% of the variance. CONCLUSION: Vascular function is associated with balance function in young adults independent of physical fitness. Increased arterial stiffness may negatively influence balance, while wave reflections may be protective for balance.

Exploration of cerebral hemodynamic pathways through which large artery function affects neurovascular coupling in young women.

Background: The interactions between large artery function and neurovascular coupling (NVC) are emerging as important contributors to cognitive health. Women are disproportionally affected by Alzheimer's disease and related dementia later in life. Understanding large artery correlates of NVC in young women may help with preservation of cognitive health with advancing age. Purpose: To explore the association between large artery function, NVC and cognitive performance in young women. Methods: Vascular measurements were made in 61 women (21 ± 4 yrs) at rest and during a cognitive challenge (Stroop task). Transcranial Doppler was used to measure left middle cerebral artery (MCA) maximum velocity (Vmax), mean velocity (Vmean), and pulsatility index (PI). NVC was determined as MCA blood velocity reactivity to the Stroop task. Large artery function was determined using carotid-femoral pulse wave velocity (cfPWV) as a proxy measure of aortic stiffness and carotid ultrasound-derived measures of compliance and reactivity (diameter change to the Stroop task). Cognitive function was assessed separately using a computerized neurocognitive battery that included appraisal of response speed, executive function, information processing efficiency, memory, attention/concentration, and impulsivity. Results: MCA Vmax reactivity was positively associated with executive function (ß = 0.26, 95% CI 0.01-0.10); MCA Vmean reactivity was negatively associated with response speed (ß = -0.33, 95% CI -0.19 to -0.02) and positively with memory score (ß = 0.28, 95% CI 0.01-0.19). MCA PI reactivity was negatively associated with attention performance (ß = -0.29, 95% CI -14.9 to -1.0). Path analyses identified significant paths (p < 0.05) between carotid compliance and carotid diameter reactivity to select domains of cognitive function through MCA reactivity. Conclusions: NVC was associated with cognitive function in young women. Carotid artery function assessed as carotid compliance and carotid reactivity may contribute to optimal NVC in young women through increased blood flow delivery and reduced blood flow pulsatility.

Twenty-Four-Hour Central Hemodynamic Load in Adults With and Without a History of COVID-19.

BACKGROUND: Although hypertension is a risk factor for severe Coronavirus Disease 2019 (COVID-19) illness, little is known about the effects of COVID-19 on blood pressure (BP). Central BP measures taken over a 24-hour period using ambulatory blood pressure monitoring (ABPM) adds prognostic value in assessing cardiovascular disease (CVD) risk compared with brachial BP measures from a single time point. We assessed CVD risk between adults with and without a history of COVID-19 via appraisal of 24-hour brachial and central hemodynamic load from ABPM. METHODS: Cross-sectional analysis was performed on 32 adults who tested positive for COVID-19 (29 ± 13 years, 22 females) and 43 controls (28 ± 12 years, 26 females). Measures of 24-hour hemodynamic load included brachial and central systolic and diastolic BP, pulse pressure, augmentation index (AIx), pulse wave velocity (PWV), nocturnal BP dipping, the ambulatory arterial stiffness index (AASI), and the blood pressure variability ratio (BPVR). RESULTS: Participants who tested positive for COVID-19 experienced 6 ± 4 COVID-19 symptoms, were studied 122 ± 123 days after testing positive, and had mild-to-moderate COVID-19 illness. The results from independent samples t-tests showed no significant differences in 24-hour, daytime, or nighttime measures of central or peripheral hemodynamic load across those with and without a history of COVID-19 (P > 0.05 for all). CONCLUSIONS: No differences in 24-hour brachial or central ABPM measures were detected between adults recovering from mild-to-moderate COVID-19 and controls without a history of COVID-19. Adults recovering from mild-to-moderate COVID-19 do not have increased 24-hour central hemodynamic load.

Central Blood Pressure and Subclinical Atherosclerotic Risk in Young Hispanic American Women.

BACKGROUND: The incidence of younger women being hospitalized from cardiovascular disease (CVD) events is on the rise. Hispanic women are generally thought to have higher CVD risk factor burden than non-Hispanic White (NHW) women yet Hispanic Americans have lower mortality from CVD. Traditional measures of CVD may not accurately capture CVD risk in Hispanic Americans. Hence, the purpose of this study was to assess the impact of ethnicity on vascular reactivity and central hemodynamic load to gain insight into subclinical CVD risk in young women. METHODS: Brachial flow-mediated dilation (FMD), low-flow mediated constriction (L-FMC), carotid-femoral pulse wave velocity (cfPWV), and pulse wave analysis (from synthesized aortic pressure waveforms) were measured in 25 Hispanic women and 31 NHW women aged between 18-35 years. FMD and L-FMC were combined to provide an index of total vessel reactivity. RESULTS: NHW and Hispanic women did not differ in age or traditional CVD risk factors (P>.05 for all). Compared with NHW women, Hispanic women had greater vascular reactivity (8.7±4.1 vs 11.7±4.1 %, P=.011), lower central pulse pressure (28±5 vs 24±3 mm Hg, P=.001) and lower pressure from wave reflections (12±2 vs 10±1 mm Hg, P=.001). There were no differences in cfPWV between NHW women and Hispanic women (5.4±0.7 vs 5.3±0.7 m/s, P=.73). CONCLUSION: Young Hispanic women have greater vascular reactivity and lower central pulsatile hemodynamic load compared with NHW women, suggesting lower subclinical CVD risk.

Sex differences in cardiovascular adaptations in recreational marathon runners.

INTRODUCTION: There are well-established sex differences in central hemodynamic and cardiac adaptations to endurance exercise; however, controversial evidence suggests that excessive endurance exercise may be related to detrimental cardiovascular adaptations in marathoners. PURPOSE: To examine left ventricle (LV) structure, LV function, 24-h central hemodynamics and ventricular-vascular coupling in male and female marathoners and recreationally active adults. METHODS: 52 marathoners (41 ± 5 years, n = 28 female, completed 6 ± 1 marathons/3 years) and 49 recreationally active controls (42 ± 5 years, n = 25 female) participated in the study. Three-Dimensional Echocardiography (3DE) was used to measure LV mass index and LV longitudinal (LS) circumferential (CS), area (AS), and radial strain (RS). An ambulatory blood pressure (BP) cuff was used to measure 24-h central hemodynamics (BP, pulse wave velocity, PWV, wave reflection index, RIx). Hemodynamic and 3DE measures were combined to derive the ratio of arterial elastance (Ea) to ventricular elastance (Elv) as a global measure of ventricular-vascular coupling. RESULTS: There were no sex or group differences in LS, CS, AS, and RS (p > 0.05). Females marathoners had similar aortic BP (116 ± 9 vs. 113 ± 1 mmHg), and PWV (5.9 ± 0.5 vs. 5.9 ± 1.1 m/s) compared to female controls but lower aSBP (116 ± 9 vs. 131 ± 10 mmHg) and PWV (5.9 ± 0.5 vs. 6.2 ± 0.5 m/s) compared to male marathoners (p < 0.05). Female marathoners had lower Ea/Elv than female controls (0.67 ± 0.20 vs. 0.93 ± 0.36) and male marathoners (0.67 ± 0.20 vs. 0.85 ± 0.42, p < 0.05). CONCLUSIONS: Women that have completed multiple marathons do not have reduced LV function or increased aortic stiffness and may have better ventricular-vascular coupling compared to male marathoners and their female untrained counterparts.

The Inverse Association of Muscular Strength with Carotid Intima-media and Extra-media Thickness in Women.

The purpose of this study was to determine the relationship between strength and atherosclerotic cardiovascular disease (CVD) risk in young women. Carotid intima-media thickness (IMT) and extra-media thickness (EMT) were used as measures of subclinical atherosclerosis and CVD risk. Muscular strength, IMT, and EMT were measured in 70 young women (mean age=21±4 years). Strength was determined using a handgrip dynamometer and expressed relative to body mass. IMT and EMT were measured using ultrasonography of the left common carotid artery. Objectively measured moderate-vigorous physical activity (MVPA) was assessed with accelerometry. Higher relative handgrip strength was associated with lower IMT (r=-0.23; p<0.05) and lower EMT (r=-0.27; p<0.05). Associations between relative handgrip strength and IMT (r=-0.24) as well as EMT (r=-0.25) remained significant after adjusting for potential confounders including traditional CVD risk factors and MVPA (p<0.05). These results show that there is an inverse association between handgrip strength with carotid IMT and EMT in young women. Muscular strength may reduce CVD risk in young women via favorable effects on subclinical carotid atherosclerosis independent of physical activity.

Reliability and validity of the COSMED K5 portable metabolic system during walking.

PURPOSE: Portable methods for assessing energy expenditure outside the laboratory and clinical environments are becoming more widely used. As such, it is important to understand the accuracy of such devices. Therefore, the purpose was to determine the reliability and validity of the COSMED K5 portable metabolic system. METHODS: Reliability and validity were assessed in 27 adults (age: 27 ± 5 years; n = 15 women) using a walking protocol. The protocol consisted of a 5-min walk/2-min rest cycle starting at 1.5 mph and increasing in 0.5-mph increments to 4.0 mph. During visit one, participants wore the K5 to assess oxygen consumption ([Formula: see text]O2), carbon dioxide production ([Formula: see text]CO2), and other metabolic variables. Two to seven days later, the protocol was repeated twice with the COSMED K5 and K4b2 systems in a randomized, counterbalanced order. RESULTS: Intraclass correlation coefficients (ICC) revealed that the K5 reliably measured [Formula: see text]O2 (ICC 0.64-0.85) and [Formula: see text]CO2 across all walking speeds (ICC 0.50-0.80), with stronger reliability at faster walking speeds compared with slower speeds. Moderate-to-strong relationships were observed for measured gases between the K5 and K4b2. Specifically, [Formula: see text]O2 exhibited a moderately high-to-high relationship between devices (r = 0.72-0.82), and a similarly moderately high-to-high relationship was observed for [Formula: see text]CO2 (r = 0.68-0.82). While there were no differences in [Formula: see text]O2 measured between devices (p ≥ 0.10), the K5 provided lower [Formula: see text]CO2 readings than the K4b2 during the 3.0, 3.5, and 4.0 mph walking speeds (p ≤ 0.02). CONCLUSIONS: The K5 provided reliable and valid measures of metabolic variables, with greater reliability and validity at faster walking speeds.

Influence of sprint exercise on aortic pulse wave velocity and femoral artery shear patterns.

PURPOSE: Aortic stiffness may affect shear patterns in the peripheral vasculature. This study examined if sprint exercise, which typically increases aortic stiffness is associated with increased peripheral retrograde blood flow and impaired microvascular function. METHODS: Twenty participants (10 women; age: 27 ± 5 years) underwent arterial stiffness, shear rate, and microvascular function assessment at three time points: baseline; following time control; ~ 2 min post a 30-s cycle ergometer sprint against 7.0% body mass. Aortic stiffness was assessed using carotid-femoral pulse wave velocity (cfPWV). Superficial femoral artery (SFA) diameter and blood velocity were assessed using Doppler-ultrasound and were used to calculate shear rates and resistance index (RI). SFA wave reflections were obtained via wave intensity analysis. Vastus medialis microvascular function was measured as tissue saturation index reactivity pre-post exercise via near-infrared spectroscopy. RESULTS: cfPWV increased by + 0.8 ± 0.7 m·s-1 following exercise (p < 0.001). Retrograde shear was reduced following exercise compared with time control (- 4.9 ± 3.8 s-1; p < 0.001), while tissue saturation index was increased post-exercise from baseline (+ 2.3 ± 4.6%; p = 0.04). Reductions in SFA wave reflections (- 1.70 ± 1.96 aU) and RI (- 0.17 ± 0.13 aU) were also noted following exercise (p < 0.001). CONCLUSION: These data suggest sprint exercise-mediated changes in peripheral shear patterns and microvascular function in the exercised vasculature occur independent from increases in aortic stiffness. Exercise-induced reductions in SFA retrograde shear may be related to decreased wave reflections and peripheral vascular resistance.

Age, sex, and the vascular contributors to cerebral pulsatility and pulsatile damping.

Cerebral pulsatility reflects a balance between the transmission and damping of pulsatility in the cerebrovasculature. Females experience greater cerebral pulsatility with aging, which may have implications for sex differences in stroke risk and cognitive decline. This study sought to explore vascular contributors to cerebral pulsatility and pulsatile damping in men and women. Adults (n = 282, 53% female) underwent measurements of cerebral (middle cerebral artery) pulsatility, pulsatile damping (ratio of cerebral to carotid pulsatility), large artery stiffening (ratio of aortic to carotid pulse wave velocity), and carotid wave transmission/reflection dynamics using wave intensity analysis. Multiple regression revealed that older age, female sex, greater large artery stiffening, higher carotid pulse pressure, and greater forward wave energy was associated with increased cerebral pulsatility (adjusted R2 = 0.44, P < 0.05). Contributors to decreased cerebral pulsatile damping included older age, female sex, and lower wave reflection index (adjusted R2 = 0.51, P < 0.05). Our data link greater large artery stiffening, carotid pulse pressure, and forward wave energy to greater cerebral pulsatility, while greater carotid wave reflection may enhance cerebral pulsatile damping. Lower cerebral pulsatile damping among females may contribute to greater age-associated cerebral pulsatile burden compared with males.NEW & NOTEWORTHY Cerebral pulsatility contributes to brain health and depends on a balance between transmission and damping of pulsatile hemodynamics into the cerebrovasculature. Our data indicate that cerebral pulsatility increases with age, female sex, extracranial artery stiffening, forward wave energy, and pulse pressure, whereas pulsatile damping decreases with age and female sex and increases with greater carotid wave reflections. These novel data identify pulsatile damping as a potential contributor to sex differences in cerebral pulsatile burden.

Preservation of Neurovascular Coupling to Cognitive Activity in Anterior Cerebrovasculature During Incremental Ascent to High Altitude.

Background: High altitude sojourn challenges blood flow regulation in the brain, which may contribute to cognitive dysfunction. Neurovascular coupling (NVC) describes the ability to increase blood flow to working regions of the brain. Effects of high altitude on NVC in frontal regions undergoing cognitive activation are unclear but may be relevant to executive function in high-altitude hypoxia. This study sought to examine the effect of incremental ascent to very high altitude on NVC by measuring anterior cerebral artery (ACA) and middle cerebral artery (MCA) hemodynamic responses to sustained cognitive activity. Materials and Methods: Eight adults (23 ± 7 years, four female) underwent bilateral measurement of ACA and MCA mean velocity and pulsatility index (PI) through transcranial Doppler during a 3-minute Stroop task at 1400, 3440, and 4240 m. Results: Resting MCA and ACA PI decreased with high-altitude hypoxia (p < 0.05). Cognitive activity at all altitudes resulted in similar increases in MCA and ACA mean velocity, and decreases in ACA and MCA PI (p < 0.05 for MCA, p = 0.07 for ACA). No significant altitude-by-Stroop interactions were detected, indicating NVC was stable with increasing altitude. Conclusions: Ascent to very high altitude (4240 m) using an incremental profile that supports partial acclimatization does not appear to disturb (1) increases in cerebral blood velocity and (2) reductions in pulsatility that characterize optimal NVC in frontal regions of the brain during cognitive activity.

Effect of external compression on femoral retrograde shear and microvascular oxygenation in exercise trained and recreationally active young men.

INTRODUCTION: Retrograde shear causes endothelial damage and is pro-atherogenic. The purpose of our study was to examine the impact of vascular remodeling from habitual exercise training on acute changes in retrograde shear and microvascular oxygenation (SMO2) induced via 30 min of external compression. METHODS: Participants included 11 exercise trained (ET) men (Division I track athletes; age 20 ± 3 years) and 18 recreationally active (RA) men (age 23 ± 5 years). Near-infrared spectroscopy (NIRS) was used to measure vastus medialis SMO2. Doppler-ultrasound was used to assess SFA intima-media thickness, diameter and flow velocity to derive retrograde shear. Vascular measures were made at baseline (BASELINE), during a sham condition (calf compression to 5 mmHg, SHAM) and during the experimental condition (calf compression to 60 mmHg, EXP). RESULTS: Compared to RA, ET had larger SFA diameters (0.66 ± 0.06 vs 0.58 ± 0.06 cm, p < 0.05) and lower SFA IMT (0.33 ± 0.03 vs 0.36 ± 0.07 mm, p < 0.05). Retrograde shear increased similarly in both groups during EXP (p < 0.05) but ET men had lower overall retrograde shear during the conditions (BASELINE 75.8 ± 26.8 vs EXP 88.2 ± 16.9 s-1) compared to RA men (BASELINE 84.4 ± 23.3 vs EXP 106.4 ± 19.6 s-1p < 0.05). There was a similar increase in SMO2 from BASELINE to SHAM (ET + 8.1 ± 4.8 vs RA + 6.4 ± 9.7%) and BASELINE to EXP (ET + 8.7 ± 6.4 vs RA + 7.1 ± 9.0%) in both groups. CONCLUSION: Beneficial vascular remodeling in ET men is associated with lower retrograde shear during external compression. Acute increases in retrograde shear with external compression do not detrimentally impact microvascular oxygenation.

Effects of Acute Aerobic Exercise on Cognition and Constructs of Decision-Making in Adults With and Without Hypertension.

Hypertension accelerates brain aging, resulting in cognitive dysfunction with advancing age. Exercise is widely recommended for adults with hypertension to attenuate cognitive dysfunction. Whether acute exercise benefits cognitive function in this at-risk population is unknown. The purpose of this study was to compare the effects of acute aerobic exercise on cognitive function in 30 middle-aged hypertensive (HTN) and 30 age, sex, and body mass index (BMI)-matched non-HTN adults (56 ± 6 years, BMI 28.2 ± 2.9 kg/m2; 32 men). Subjects underwent cognitive testing pre/post 30-min cycling (≈55% peak oxygen consumption). Cognition was assessed using standard metrics of accuracy and reaction time (RT) across memory recognition, 2-back, and Flanker tasks. Behavioral data was further analyzed using drift-diffusion modeling to examine underlying components of decision-making (strength of evidence, caution, bias) and RT (non-decision time). Exercise elicited similar changes in cognitive function in both HTN and non-HTN groups (p > 0.05). Accuracy was unaltered for Flanker and 2-back tasks, while hits and false alarms increased for memory recognition post-exercise (p < 0.05). Modeling results indicated changes in memory hits/false alarms were due to significant changes in stimulus bias post-exercise. RT decreased for Flanker and memory recognition tasks and was driven by reductions in post-exercise non-decision time (p < 0.05). Our data indicate acute exercise resulted in similar, beneficial cognitive responses in both middle-age HTN and non-HTN adults, marked by unaltered task accuracy, and accelerated RT post-exercise. Additionally, drift-diffusion modeling revealed that beneficial acceleration of cognitive processing post-exercise (RT) is driven by changes in non-decision components (encoding/motor response) rather than the decision-making process itself.

Changes in cognitive function and latent processes of decision-making during incremental ascent to high altitude.

High altitude sojourn is broadly associated with impaired cognitive function, although there are inconsistencies within the literature. Incorporation of mathematical modeling to gain insight into latent aspects of decision-making may strengthen the ability to characterize changes in cognitive function during high altitude sojourn. This study sought to examine the effects of high altitude on cognitive function and underlying constructs of decision-making during an 11-d incremental ascent to 5160 m in 18 healthy adults (26 ±â€¯12 yrs). Participants underwent cognitive testing at 116 m, 3440 m, 4240 m, and 5160 m. Cognitive function was assessed using standard metrics of accuracy and reaction time (RT) during working memory (2-back) and attention (Flanker) tasks. Behavioral data were additionally analyzed using drift-diffusion modeling to interrogate latent neural (strength of evidence, non-decision time) and behavioral (caution, bias) processes of decision-making. Flanker accuracy was unaltered during incremental ascent to high altitude, while 2-back accuracy decreased at 5160 m (p < 0.01). RT was faster at 4240 m for the Flanker, and faster at all altitudes compared to 116 m for the 2-back (p < 0.01). Incremental ascent to high altitude elicited modest reductions in caution and non-decision time, increases in bias and strength of evidence for non-match items during the 2-back (0.04 ≥ p > 0.01). These data indicate that while RT may appear to improve during incremental ascent to high altitude, increases in speed may be driven by participants 1) accumulating less evidence before initiating a response (i.e., less cautious) and 2) preferentially attending to (more biased), and extracting more evidence from, frequent/easier stimuli, rather than improved processing per se. Taken together, changes in cognitive function during incremental ascent to high altitude may reflect subtle changes in neural and behavioral components of decision-making intended to reduce cognitive load and conserve brain resources under challenging environmental conditions.

Aortic stiffness, central pulse pressure and cognitive function following acute resistance exercise.

INTRODUCTION: While resistance exercise (RE) is known to be beneficial for overall health, one bout of RE acutely increases aortic stiffness and pulse pressure (PP). Increases in aortic stiffness and PP in a setting of aging has been shown to detrimentally impact cognitive function. This study examined whether increased aortic stiffness and PP from an acute bout of RE is associated with cognitive function. METHODS: Thirty-five participants (21 ± 2 years) underwent cognitive testing before and after either an acute bout of RE or a non-exercise time-control condition. Cognitive function was assessed as reaction time and accuracy during memory recognition, attention (Flanker) and working memory (N-back) tasks. Aortic stiffness and PP were measured via pulse wave velocity (PWV) and pulse wave analysis, respectively, using a brachial oscillometric device. RESULTS: There were significant increases in aortic PWV and aortic PP following RE (p < 0.05) with no change in PWV or PP following the non-exercise control condition (p > 0.05). There was no change in accuracy metrics (% hits) across conditions for any cognitive task (p > 0.05). There was a condition-by-time interaction for reaction time for the memory task (p < 0.05) driven by a significant decrease in reaction times following RE (p < 0.05) with no change in reaction time following the non-exercise control (p > 0.05). CONCLUSION: Functional increases in aortic stiffness and pulse pressure following acute RE occur in the absence of detrimental changes in cognitive function in young, healthy adults.

Neurovascular coupling during cognitive activity in adults with controlled hypertension.

Hypertension, even when controlled, may accelerate arterial stiffening and impair the ability of the cerebrovasculature to increase blood flow to support neural activity, i.e., neurovascular coupling (NVC). Optimal NVC depends on continuous, nonpulsatile flow, which is partially determined by extra- and intracranial vessel function. We sought to compare extra- and intracranial hemodynamics during cognitive activity (Stroop task) in 30 middle-aged, well-controlled medicated hypertensive and 30 age-, sex-, and body mass index (BMI)-matched nonhypertensive adults (56 ± 6 years, 28.2 ± 2.9 kg/m2 BMI; 32 men). Aortic and carotid (single point) pulse wave velocity (PWV) were assessed via tonometry and ultrasound, respectively. Carotid and middle cerebral artery (MCA) blood velocity pulsatility were measured via ultrasound and Doppler. Prefrontal cortex (PFC) oxygenation was measured via tissue saturation index (TSI) using near-infrared spectroscopy. Accuracy and reaction times were computed to assess cognitive performance. Stroop performance was similar between groups ( P > 0.01). Aortic and carotid PWV increased, carotid flow pulsatility decreased ( P < 0.01), and MCA flow pulsatility and PFC TSI were maintained during Stroop ( P > 0.01). Our findings indicate that middle-age adults with medically controlled hypertension and adults without hypertension demonstrate similar intra- and extracranial cerebrovascular reactivity during cognitive engagement. Despite increases in large artery stiffness, middle-aged adults with controlled hypertension and without hypertension exhibit reductions in extracranial flow pulsatility during cognitive engagement that may be part of a concerted cerebrovascular response to support downstream cerebral oxygenation and overall NVC. NEW & NOTEWORTHY Hypertension is associated with accelerated arterial stiffening, which may alter extra- and intracranial vascular reactivity during cognitive activity and impair neurovascular coupling. Middle-aged adults with medicated hypertension exhibit similar neurovascular coupling and extra-/intracranial vascular reactivity during sustained cognitive activity. Extracranial modulation of central hemodynamics may be an important component of optimal neurovascular coupling.

Effects of acute aerobic exercise on arterial stiffness and cerebrovascular pulsatility in adults with and without hypertension.

OBJECTIVES: Stiffer central arteries, as seen in hypertension (HTN), foster transmission of pulsatile hemodynamics into fragile cerebral vessels. Aerobic exercise is recommended for adults with HTN, but its effects on arterial stiffness and pulsatility in this group are unclear. This study sought to investigate the effect of acute aerobic exercise on arterial stiffness and cerebrovascular pulsatility in 30 adults with treated HTN and 30 age, sex, and BMI-matched adults without HTN (56 ±â€Š6 years, BMI 28.2 ±â€Š2.9 kg/m; 28 women). METHODS: Patients underwent hemodynamic measures before/after 30-min cycling (≈55% peak oxygen consumption). Aortic stiffness was measured using carotid-femoral pulse wave velocity, and carotid artery stiffness was assessed with ß-stiffness via ultrasound. Aortic/carotid pulse pressure (aortic via radial generalized transfer function) was measured by tonometry and calibrated to brachial mean pressure and diastolic pressure. Carotid/middle cerebral artery (MCA) blood velocity pulsatility indices were measured using Doppler. Carotid wave intensity analysis was used to derive forward wave intensity (W1). RESULTS: Exercise impacted hemodynamics similarly in HTN compared to no-HTN. Carotid-femoral pulse wave velocity, MCA pulsatility index, carotid pulsatility index, and W1 increased similarly after exercise in both groups (P < 0.05). Carotid pulse pressure and ß-stiffness were unaltered after exercise. Postexercise changes in W1 were positively associated with carotid pulsatility index, which was further associated with MCA pulsatility index. CONCLUSIONS: These data suggest adults with treated HTN experience similar increases in aortic stiffness and cerebrovascular hemodynamic pulsatility during early recovery from acute aerobic exercise as their counterparts without HTN.