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.

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.

Sex differences in the association between PTSD symptoms with cardiac autonomic function and subclinical atherosclerotic risk.

BACKGROUND: Post-traumatic stress disorder (PTSD) is a public health concern that may elevate the risk for cardiovascular disease (CVD). There are established sex differences in both PTSD risk and CVD risk. PURPOSE: To examine sex-specific associations between subclinical PTSD symptom severity and subclinical CVD risk in young men and women. METHODS: A total of 61 young adults (women: n = 29, mean age: 26 ± 7 years) completed the post-traumatic stress disorder civilian checklist (PCL) and the Center for Epidemiologic Studies Depression Scale (CES-D). Aortic stiffness was measured as carotid-femoral pulse wave velocity (cfPWV). Peripheral vasomotor function was measured as flow-mediated slowing (FMS) of carotid-radial PWV following 5-min forearm occlusion. Heart rate variability was used to assess sympathovagal balance as LF/HF ratio. RESULTS: PCL score was positively correlated with CES-D score (r = 0.79, p < .001), cfPWV (r = 0.33, p = .03) and LF/HF ratio (r = 0.42, p = .009) in men. PCL score was positively correlated to CES-D score (r = 0.80, p < .001) in women, but was inversely correlated to cfPWV (r = -0.38, p = .02) and LF/HF ratio (r = -0.34, p = .04). PCL score was also inversely associated with FMS in women (r = -0.49, p = .01). CONCLUSION: There are sex differences in the association of PTSD symptoms and subclinical atherosclerosis. In men, increased PTSD symptoms may increase CVD risk by increasing sympathovagal balance and aortic stiffness. In women, increased PTSD symptoms may increase CVD risk via reducing vasomotor function.

Racial Differences in Left Ventricular Mass and Wave Reflection Intensity in Children.

The burden of heart failure is disproportionately higher in African Americans, with a higher prevalence seen at an early age. Examination of racial differences in left ventricular mass (LVM) in childhood may offer insight into risk for cardiac target organ damage (cTOD) in adulthood. Central hemodynamic load, a harbinger of cTOD in adults, is higher in African Americans. The purpose of this study was to examine racial differences in central hemodynamic load and LVM in African American and non-Hispanic white (NHW) children. Two hundred sixty-nine children participated in this study (age, 10 ± 1 years; n = 149 female, n = 154 African American). Carotid pulse wave velocity (PWV), forward wave intensity (W1) and reflected wave intensity (negative area, NA) was assessed from simultaneously acquired distension and flow velocity waveforms using wave intensity analysis (WIA). Wave reflection magnitude was calculated as NA/W1. LVM was assessed using standard 2D echocardiography and indexed to height as LVM/[height (2.16) + 0.09]. A cutoff of 45 g/m (2.16) was used to define left ventricular hypertrophy (LVH). LVM was higher in African American vs. NHW children (39.2 ± 8.0 vs. 37.2 ± 6.7 g/m (2.16), adjusted for age, sex, carotid systolic pressure and socioeconomic status; p < 0.05). The proportion of LVH was higher in African American vs. NHW children (25 vs. 12 %, p < 0.05). African American and NHW children did not differ in carotid PWV (3.5 ± 4.9 vs. 3.3 ± 1.3 m/s; p > 0.05). NA/W1 was higher in African American vs. NHW children (8.5 ± 5.3 vs. 6.7 ± 2.9; p < 0.05). Adjusting for NA/W1 attenuated racial differences in LVM (38.8 ± 8.0 vs. 37.6 ± 7.0 g/m (2.16); p = 0.19). In conclusion, racial differences in central hemodynamic load and cTOD are present in childhood. African American children have greater wave intensity from reflected waves and higher LVMI compared to NHW children. WIA offers novel insight into early life origins of racial differences in central hemodynamic load and cTOD.

Autonomic modulation following an acute bout of bench press with and without blood flow restriction.

PURPOSE: Traditional resistance exercise decreases vagal tone up to 30 min after an acute bout of resistance exercise, which may increase the risk of cardiovascular events. However, the effects of resistance exercise with blood flow restriction (BFR) on autonomic modulation are unclear. To evaluate autonomic modulation after resistance exercise with and without BFR in resistance-trained men. METHODS: Eleven young men volunteered for the study. Autonomic modulation was assessed at rest, 15 (Rec 1), and 25 (Rec 2) minutes after low-load bench press with BFR (LL-BFR), traditional high-load bench press (HL), and a control (CON). Autonomic modulation assessments were expressed as natural logarithm (Ln), and included total power (LnTP), low-frequency power (LnLF), high-frequency power (LnHF), sympathovagal balance (LnLF/LnHF ratio), root mean square of the successive differences (LnRMSSD), and the proportion of intervals differing by > 50 ms from the preceding intervals (LnPNN50). A repeated measures ANOVA was used to evaluate conditions (LL-BFR, HL and CON) across time (Rest, Rec1, and Rec2) on autonomic modulation. RESULTS: There were significant condition by time interactions for LnTP, LnHF, and LnRMSSD such that they were reduced during recovery after LL-BFR and HL compared to Rest and CON. There were no interactions in the LnLF, LnLF/LnHF ratio, and LnPNN50. CONCLUSIONS: These data suggest that LL-BFR and HL significantly alter autonomic modulation up to 30 min after exercise with significant reduction after HL compared to LL-BFR when exercise volume is equated.

Pulse wave reflection responses to bench press with and without practical blood flow restriction.

Resistance exercise is recommended to increase muscular strength but may also increase pulse wave reflection. The effect of resistance exercise combined with practical blood flow restriction (pBFR) on pulse wave reflection is unknown. The purpose of this study was to evaluate the differences in pulse wave reflection characteristics between bench press with pBFR and traditional high-load bench press in resistance-trained men. Sixteen resistance-trained men participated in the study. Pulse wave reflection characteristics were assessed before and after low-load bench press with pBFR (LL-pBFR), traditional high-load bench press (HL), and a control (CON). A repeated-measures ANOVA was used to evaluate differences in pulse wave reflection characteristics among the conditions across time. There were significant (p ≤ 0.05) interactions for heart rate, augmentation index, augmentation index normalized at 75 bpm, augmentation pressure, time-tension index, and wasted left ventricular energy such that they were increased after LL-pBFR and HL compared with rest and CON, with no differences between LL-pBFR and HL. Aortic pulse pressure (p < 0.001) was elevated only after LL-pBFR compared with rest. In addition, there was a significant (p ≤ 0.05) interaction for aortic diastolic blood pressure (BP) such that it was decreased after LL-pBFR compared with rest and CON but not HL. The subendocardial viability ratio and diastolic pressure-time index were significantly different between LL-pBFR and HL compared with rest and CON. There were no significant interactions for brachial systolic or diastolic BP, aortic systolic BP, or time of the reflected wave. In conclusion, acute bench press resistance exercise significantly altered pulse wave reflection characteristics without differences between LL-pBFR and HL.

Autonomic modulation and baroreflex sensitivity after acute resistance exercise: responses between sexes.

BACKGROUND: The aim of this study was to evaluate autonomic modulation, blood pressure variability and baroreflex sensitivity (BRS) responses to an acute bout of free-weight resistance exercise in resistance-trained men (N.=14) and women (N.=13). METHODS: Participants underwent both an acute bout of resistance exercise (RE) consisting of 3 sets of 10 repetitions at 75% 1-repetition maximum on the squat, bench press, and deadlift, and a quiet control. Autonomic modulation, blood pressure variability (LFSAP), and cardiovagal BRS were assessed at rest, 15-20 minutes (Rec1) and 25-30 minutes (Rec2) postexercise. Log transformed measures of autonomic modulation included root square of the mean ssquared differences of successive RR intervals (LnRMSSD), high-frequency power (LnHFRR) and low-frequency power (LnLFRR) and sympathovagal balance (LnLFRR/HFRR). LFSAP was used as a measurement of vasomotor tone. Cardiovagal BRS was assessed using the sequence method. RESULTS: There were no significant sex differences at rest and no significant sex by time by condition interactions for any variable. Compared with rest there were augmentations in LnLFRR/HFRR (P=0.002) and LFSAP (P=0.001) at Rec1 and Rec2. RMSSD and cardiovagal BRS were significantly (P=0.0001) decreased at Rec1 and Rec2 compared to rest after the acute RE. CONCLUSIONS: Both sexes demonstrated that acute resistance exercise using free weights has a profound impact on autonomic modulation, blood pressure variability and cardiovagal BRS.

Free-weight resistance exercise on pulse wave reflection and arterial stiffness between sexes in young, resistance-trained adults.

We sought to determine the sex-specific effects of an acute bout of free-weight resistance exercise (RE) on pulse wave reflection (aortic blood pressures, augmentation index (AIx), AIx at 75 bpm (AIx@75), augmentation pressure (AP), time of the reflected wave (Tr), subendocardial viability ratio (SEVR)), and aortic arterial stiffness in resistance-trained individuals. Resistance-trained men (n = 14) and women (n = 12) volunteered to participate in the study. Measurements were taken in the supine position at rest, and 10 minutes after 3 sets of 10 repetitions at 75% 1-repetition maximum on the squat, bench press, and deadlift. A 2 × 2 × 2 ANOVA was used to analyse the effects of sex (men, women) across condition (RE, control) and time (rest, recovery). There were no differences between sexes across conditions and time. There was no effect of the RE on brachial or aortic blood pressures. There were significant condition × time interactions for AIx (rest: 12.1 ± 7.9%; recovery: 19.9 ± 10.5%, p = .003), AIx@75 (rest: 5.3 ± 7.9%; recovery: 24.5 ± 14.3%, p = .0001), AP (rest: 4.9 ± 2.8 mmHg; recovery: 8.3 ± 6.0 mmHg, p = .004), and aortic arterial stiffness (rest: 5.3 ± 0.6 ms; recovery: 5.9 ± 0.7 ms, p = .02) with significant increases during recovery from the acute RE. There was also a significant condition × time for time of the reflected wave (rest: 150 ± 7 ms; recovery: 147 ± 9 ms, p = .02) and SEVR (rest: 147 ± 17%; recovery: 83 ± 24%, p = .0001) such that they were reduced during recovery from the acute RE compared to the control. These data suggest that an acute bout of RE increases AIx, AIx@75, and aortic arterial stiffness similarly between men and women without significantly altering aortic blood pressures.

Resistance Exercise Training on Disease Impact, Pain Catastrophizing and Autonomic Modulation in Women with Fibromyalgia.

Women with fibromyalgia (FM) often complain of whole-body pain, and muscle fatigue, which may be related to autonomic dysfunction. Therefore, the purpose of the present study was to investigate the effects of resistance exercise training (RET) on disease impact, pain catastrophizing, and autonomic modulation in women with FM. Women with FM (n=26) and healthy control women (HC: n=9), aged 19-65 yrs, were compared at rest. Women with FM were randomly assigned to a resistance-training group (FM-RT: n=14) or a non-exercising control group (FM-CON: n=12). Women in the FM-RT group underwent 8-weeks of RET on 4 different exercises, 2 times per week, 3 sets of 8-12 repetitions at 50%-60% of the pre-determined 1-repetition max (1RM). Autonomic modulation was assessed using heart rate variability and heart rate complexity. Healthy control women had a lower resting heart rate, decreased normalized low-frequency power, and increased normalized high-frequency power compared to the FM groups at rest. After the 8-week intervention, significant increases (p ≤ 0.05) in 1RM were observed for both chest press and leg extension for women in the RT group. Disease impact was significantly reduced (p ≤ 0.05) for participants in the FM-RT group (FM-RT: 59±12 to 41±24 units; FM-CON: 72±7 to71±8 units), but pain catastrophizing was unaltered. There were no significant changes in autonomic modulation after the RET intervention. These data demonstrate that while women with FM may still have autonomic dysfunction after undergoing a RET program, disease impact was significantly reduced.