Normotensive Young Men Research Articles

Synergist upper-limb resistance training reduces blood pressure in young normotensive men: a piloty study

Synergist upper-limb resistance training reduces blood pressure in young normotensive men: a piloty study

Exploring the Influence of a Single Bout of Tahajjud Prayer on Acute Blood Pressure Response in Normotensive Young Adult Males with Varied Regularity of Tahajjud Practice

Tahajjud, a type of sunnah worship for Muslims, involves standard rules and complex movements that contribute to cardiovascular health and blood pressure regulation. Aims and scope: This study aimed to analyze the effect of a single bout of tahajud, on systolic (SBP) and diastolic blood pressure (DBP) in normotensive young men. The study employed an experimental design with healthy men aged 18-25 and normal blood pressure (normotensive). It included a control group (n = 12) that did not perform Tahajjud and a trial group (n = 12) that regularly practiced Tahajjud for over six weeks. The treatment involved performing Tahajjud consisting of 11 raka'at from 3:30-4:30 a.m., lasting 25-35 minutes. Blood pressure was measured using a sphygmomanometer before and after Tahajjud, and data analysis utilized a t-test (p < .05). These findings indicate that there is a non-significant difference in the mean of SBP and DBP after midnight between the control and trial groups, SBP (mmHg): 110.42±9.16 and 114.58±4.98 vs 120±6.03, p = .11 and 115±6.74, p = .08. DBP (mmHg): 76.77±4.92 and 77.50±4.52, p = .58 vs. 81.67±8.35 and 79.17±5.15, p = .19, SBP and DBP decreased by 5 mmHg and 2.5 mmHg in the trial group. Tahajjud, regardless of regularity, can elicit a modest but non-significant reduction in both SBP and DBP. These results indicate that Tahajjud may have a potential role in promoting cardiovascular health. Further research is warranted to examine the long-term effects and underlying mechanisms of Tahajjud on BP regulation.

Barosensory vessel mechanics and the vascular sympathetic baroreflex: Impact on blood pressure homeostasis.

What is the topic of this review? We review barosensory vessel mechanics and their role in blood pressure regulation across the lifespan. What advances does it highlight? In young normotensive men, aortic unloading mechanics contribute to the resting operating point of the vascular sympathetic baroreflex; however, with advancing age, this contribution is removed. This suggests that barosensory vessel unloading mechanics are not driving the well-documented age-related increase in resting muscle sympathetic nerve activity. An age-associated increase in arterial blood pressure is evident for apparently healthy humans. This is frequently attributed to stiffening of the central arteries and a concurrent increase in sympathetic outflow, potentially mediated by a reduced ability of the baroreceptive vessels to distend. This is supported, in part, by a reduced mechanical component of the vascular sympathetic baroreflex (i.e., a reduction in distension for a given pressure). Previous characterization of the mechanical component has assessed only carotid artery distension; however, evidence suggests that both the aortic and carotid baroreflexes are integral to blood pressure regulation. In addition, given that baroreceptors are located in the vessel wall, the change in wall tension, comprising diameter, pressure and vessel wall thickness, and the mechanics of this change might provide a better index of the baroreceptor stimulus than the previous method used to characterize the mechanical component that relies on diameter alone. This brief review summarizes the data using this new method of assessing barosensory vessel mechanics and their influence on the vascular sympathetic baroreflex across the lifespan.

SALT-SENSITIVITY IN HEALTHY NORMOTENSIVE MEN IS ASSOCIATED WITH IMPAIRED BAROREFLEX SENSITIVITY

Objective: Blood pressure (BP) responses to Na+ intake show great variability, discriminating sodium sensitive (SS) from salt resistant (SR) individuals. The pathophysiology behind salt-sensitivity is still not fully elucidated. A pivotal role for the sympathetic nervous system to BP increase after sodium loading is suggested. Therefore, we aimed to investigate the effect of the sympathovagal balance on Na+-induced BP effects and if Na+-induced effects on sympathetic activation contribute to salt-sensitivity. Design and method: We performed a randomized cross-over study in 31 young healthy men with normal BMI and eGFR. Subjects followed both an 8-day low Na+ diet (LSD, < 50mmol/d) and high Na+ diet (HSD, > 200mmol/d), in 18 subjects the diets were extended to 14-days. SS was defined as an increase of three or more mmHg standardized measured office MAP after HSD. Cardiac-output (CO) and cross correlation baroreflex sensitivity (xBRS) were measured with continuous non-invasive finger photoplethysmography. Systemic vascular resistance (SVR) was calculated as the ratio of MAP by CO. Results: After HSD, SS men (19%) showed a mean 6.2 (±2.1 SD) mmHg increase in MAP. No absolute differences in Na+-induced effects on CO and SVR could be observed between groups. After HSD, xBRS was 34% lower in SS men compared to SR men (Fig1A). Sodium loading resulted in a mean xBRS decrease of 3.4 (±6.5 SD) ms/mmHg in SS men, whilst xBRS increased with 2.3 (±6.3 SD) ms/mmHg in SR men (p = 0.06). HSD xBRS values were significantly correlated with Na+-induced BP changes in the complete group when corrected for age and BMI (Fig1B). Conclusions: Salt-sensitivity of BP in young normotensive men seems to be predominantly driven by changes in sympathovagal balance. The significant correlation between xBRS and delta BP further suggests a continuous relation between sympathetovagal balance and salt exposure. Further studies are needed to unravel pathophysiological mechanisms underlying Na+-effects on sympathetic regulation.

Resting Sympathetic Transduction in Young Healthy non‐Hispanic Black Women: Potential Race and Sex Differences

BackgroundThe prevalence of hypertension (HTN) is highest in the non‐Hispanic Black (BL) population. Notably, BL women have an equal or greater HTN prevalence compared to BL men; however, limited studies have included women. Heightened sympathetic nervous system reactivity has been proposed as a potential mediator of elevated HTN risk in the BL population. In this regard, our laboratory previously demonstrated exaggerated sympathetic transduction at rest in young normotensive BL men compared to their non‐Hispanic white (WH) counterparts. Whether similar responses are present in BL women is not known. Furthermore, whether there are sex differences in sympathetic transduction in young BL adults remains unclear.HypothesisWe hypothesized that BL women would exhibit elevated resting sympathetic transduction compared to WH women, and that sympathetic transduction would be comparable between BL women and men.MethodsSix young healthy BL women (age: 20 ± 1 years), six WH women (age: 21 ± 1 years) and six BL men (age: 21 ± 1 years) were studied. Heart rate (ECG), muscle sympathetic nerve activity (MSNA; peroneal microneurography) and beat‐to‐beat blood pressure (BP; Finometer) were continuously measured under resting conditions for 19 ± 1 min. Sympathetic transduction was quantified as peak changes in mean arterial pressure (MAP) and the nadir of total vascular conductance (TVC) over 10 cardiac cycles following spontaneous bursts of MSNA using signal‐averaging. All data are expressed as mean ± SEM.ResultsResting BP and heart rate were not different between groups (all P > 0.05). Likewise, BL women had similar MSNA burst frequency (BL women: 12 ± 2 vs. WH women: 14 ± 1 bursts/min; P = 0.475) and burst incidence (BL women: 21 ± 2 vs. WH women: 24 ± 2 bursts/100 cardiac cycles; P = 0.477) compared to WH women, and BL men (13 ± 1 bursts/min, 21 ± 1 bursts/100 cardiac cycles; P = 0.539). For peak increases in MAP following MSNA bursts, there were no differences between BL and WH women (BL women: Δ+2.3 ± 0.4 vs. WH women: Δ+2.1 ± 0.2 mmHg; P = 0.741). Peak reductions in TVC were also not different in women (BL women: Δ‐2.1 ± 0.3 vs. WH women Δ‐2.4 ± 0.6 mL/min/mmHg; P = 0.966). However, in comparison to BL men, BL women had lower MAP (women: Δ+2.3 ± 0.4 vs. men: Δ+5.5 ± 1.1 mmHg; P = 0.011) and TVC (P = 0.036) responses.ConclusionContrary to our hypothesis, these preliminary data suggest similar beat‐to‐beat sympathetic transduction at rest in BL and WH women. Interestingly, sympathetic transduction at rest was lower in BL women compared to BL men highlighting a potential differential effect of sex on BP regulation in young BL adults. Collectively, these findings suggest that augmented sympathetic transduction is not likely an early contributor to the greater prevalence of HTN in BL women.

Aortic haemodynamics: the effects of habitual endurance exercise, age and muscle sympathetic vasomotor outflow in healthy men

PurposeWe determined the effect of habitual endurance exercise and age on aortic pulse wave velocity (aPWV), augmentation pressure (AP) and systolic blood pressure (aSBP), with statistical adjustments of aPWV and AP for heart rate and aortic mean arterial pressure, when appropriate. Furthermore, we assessed whether muscle sympathetic nerve activity (MSNA) correlates with AP in young and middle-aged men.MethodsAortic PWV, AP, aortic blood pressure (applanation tonometry; SphygmoCor) and MSNA (peroneal microneurography) were recorded in 46 normotensive men who were either young or middle-aged and endurance-trained runners or recreationally active nonrunners (10 nonrunners and 13 runners within each age-group). Between-group differences and relationships between variables were assessed via ANOVA/ANCOVA and Pearson product-moment correlation coefficients, respectively.ResultsAdjusted aPWV and adjusted AP were similar between runners and nonrunners in both age groups (all, P > 0.05), but higher with age (all, P < 0.001), with a greater effect size for the age-related difference in AP in runners (Hedges’ g, 3.6 vs 2.6). aSBP was lower in young (P = 0.009; g = 2.6), but not middle-aged (P = 0.341; g = 1.1), runners compared to nonrunners. MSNA burst frequency did not correlate with AP in either age group (young: r = 0.00, P = 0.994; middle-aged: r = − 0.11, P = 0.604).ConclusionThere is an age-dependent effect of habitual exercise on aortic haemodynamics, with lower aSBP in young runners compared to nonrunners only. Statistical adjustment of aPWV and AP markedly influenced the outcomes of this study, highlighting the importance of performing these analyses. Further, peripheral sympathetic vasomotor outflow and AP were not correlated in young or middle-aged normotensive men.

Effects of isometric leg training on ambulatory blood pressure and morning blood pressure surge in young normotensive men and women

Despite the reported association between diurnal variations in ambulatory blood pressure (BP) and elevated cardiovascular disease risk, little is known regarding the effects of isometric resistance training (IRT), a practical BP-lowering intervention, on ambulatory BP and morning BP surge (MBPS). Thus, we investigated whether (i) IRT causes reductions in ambulatory BP and MBPS, in young normotensives, and (ii) if there are any sex differences in these changes. Twenty normotensive individuals (mean 24-h SBP = 121 ± 7, DBP = 67 ± 6 mmHg) undertook 10-weeks of bilateral-leg IRT (4 × 2-min/2-min rest, at 20% maximum voluntary contraction (MVC) 3 days/week). Ambulatory BP and MBPS (mean systolic BP (SBP) 2 h after waking minus the lowest sleeping 1 h mean SBP) was measures pre- and post-training. There were significant reductions in 24-h ambulatory SBP in men (− 4 ± 2 mmHg, P = 0.0001) and women (− 4 ± 2 mmHg, P = 0.0001) following IRT. Significant reductions were also observed in MBPS (− 6 ± 8 mmHg, p = 0.044; − 6 ± 7 mmHg, P = 0.019), yet there were no significant differences between men and women in these changes, and 24-h ambulatory diastolic BP remained unchanged. Furthermore, a significant correlation was identified between the magnitude of the change in MBPS and the magnitude of changes in the mean 2-h SBP after waking for both men and women (men, r = 0.89, P = 0.001; women, r = 0.74, P = 0.014). These findings add further support to the idea that IRT, as practical lifestyle intervention, is effective in significantly lowering ambulatory SBP and MBPS and might reduce the incidence of adverse cardiovascular events that often occur in the morning.

Phenotypes of vascular aging in young people, taking into account the level of blood pressure

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): State Task Introduction. Assessment of vascular age (VA), based on the determination of the arterial stiffness (AS), is attracting more and more attention of specialists, since this risk factor (FR) has proven the reclassifying and prognostic potential. The definition of VA is of particular importance for young people (YP), as they may have the high relative cardiovascular risk with low absolute risk. However, until now, this contingent has not been studied in the aspect of possible association of AS and blood pressure (BP) levels. The aim - to assess the representation of the different phenotypes of VA in YP, depending on level of BP, taking into account gender. Material and methods. 250 YP (88 boys and 162 girls) aged from 18 to 25 years were examined on basis of the University Health Center within framework of the National Preventive Project "University - Territory of Health". Angiological screening was performed using VaSera VS-1500 device (Fukuda Denshi, Japan), which allows to evaluate such an indicator AS as cardio-ankle vascular index (CAVI). Since the values on left side were higher than on right side, the results are presented according to CAVI-L. All YP are divided into tercile groups according to CAVI, taking into account gender. This stiffness indicator, unlike others, does not depend on the level of BP acting on arterial wall at the time of registration of the pulse wave. In accordance with opinion of experts, such interval analysis in sample homogeneous by sex and age allows us to identify carriers of the phenotypes of early or premature VA (upper CAVI-tercile group), normal VA (middle CAVI-tercile grope) and favorable or healthy VA ( first CAVI-tercile group). Early VA is also called EVA syndrome. The group of elevated office BP was formed from carriers of high normal (HN) BP (130-139/85-89 mm Hg) and arterial hypertension(AH) (140/90 mm Hg and above); еhe group of normal office pressure from individuals with BP of 129/84 mm Hg and below. Data processing was carried out using software package "Statistica 10.0" ( StatSoft Inc, USA). Results. It was found that from the first to the third CAVI-tercile group of 41 normotensive young men turned out to be 14(34,1%), 12(29,3%), 15(36,6%) at P = 0.657 and out of 47 hypertensive young men 15(31,9%), 17(36,2%), 15(31,9%) at P = 0.785. In these tercile groups of 135 normotensive girls was found to be 43(31,8%), 45(33,4%), 47(34,8%) at P = 0.852 and out of 27 hypertensive girls 11(40,7%) 9(33,4%), 7(25,9%) at p = 0.348. These data indicate that among young carriers of both office normotension and office HNBP/AH, the EVA phenotype was almost as common as the phenotypes of normal VA and favorable VA. This applied to both boys and girls about equally. Conclusion. The obtained results indicate expediency of using angiological screening to early identify phenotypes of VA in the framework of preventive measures among young people, regardless of the level of their initial office BP.

An Evaluation of the Frequency and Severity of Erectile Dysfunction in Hypertensive Married Men Compared with Normotensive Married Men

Background: Erectile dysfunction (ED) exerts a major burden on the quality of life of the patients and their sexual partners. It has been identified as an independent risk factor for cardiovascular disease. Hypertension is a well-established risk factor for ED. Both hypertension and erectile dysfunction has age dependent relationship. Objective: To evaluate the frequency and severity of erectile dysfunction in hypertensive married men compared with normotensive married men of similar demographic characteristics attending a tertiary care hospital of Bangladesh during the period from June 2017 to March, 2018. Methodology: This cross-sectional comparative study includes 75 hypertensive and 75 normotensive young and middle-aged married men (31–59 years) those visited our outpatient clinic. From them, 75 patients had hypertension and 75 were normotensive. Erectile dysfunction was evaluated with pre validated Bengali version of the International Index of Erectile Function (IIEF-5) questionnaire. Results: Erectile dysfunction (ED) was found in 61.3% of patients with hypertension compared with 37.3% of normotensive subjects. ED is more common and more severe among hypertensive patients than normotensive counterparts. Hypertension duration, hypertension severity and age were found positively correlated with erectile dysfunction. Taking regular medication and control of BP gave positive influence upon erectile status. No association was found between ED and smoking but a weak negative correlation of increased body mass index (BMI) and decreased ED was found in both hypertensive and normotensive group. Conclusion: Hypertensive patients present with erectile dysfunction more frequently than age matched normotensive individuals. As erectile dysfunction is a matter of embarrassment, doctors should be motivated to discuss such issue. Control of blood pressure seems to confer good influence upon the prevalence of erectile status. We need further studies to authenticate such observation and to unveil other risk factors of ED in our country and to go for appropriate management.

Acute Hemodynamic Responses to Repetitions to Failure Using Different Resistance Exercises and Protocols in Normotensive Men: A crossover study

ABSTRACTThe present crossover design study investigated acute hemodynamic responses to two sets of leg press (LP) and bench press (BeP) at 10 and 20 repetition maximum (RM) in ten normotensive young men. At the end of each set, an increase in systolic blood pressure (SBP), heart rate (HR), and rate pressure product (RPP) was observed (p < .01), with no differences between intensities, but SBP was greater during the LP exercise (p < .01). Lower resting values of diastolic blood pressure (DBP) were observed in the post-BeP exercise period (p < .05), suggesting that DBP post-exercise hypotension may be more evident after upper-limb exercise.

Effect of time of exercise and posture on 24-h post-exercise blood pressure in young normotensive men

Effect of time of exercise and posture on 24-h post-exercise blood pressure in young normotensive men

Device-guided slow breathing reduces blood pressure and sympathetic activity in young normotensive individuals of both sexes.

Slow breathing (SLOWB) is recommended for use as an adjuvant treatment for hypertension. However, the extent to which blood pressure (BP) responses to SLOWB differ between men and women are not well-established. Therefore, we tested the hypothesis that an acute bout of SLOWB would induce larger decreases in BP in males than in females, given that males typically have higher resting BP. We also examined autonomic contributors to reduced BP during SLOWB; that is, muscle sympathetic nerve activity and spontaneous cardiovagal (sequence method) and vascular sympathetic baroreflex sensitivity. We tested normotensive females (n = 10, age: 22 ± 2 y, body mass index: 22 ± 2 kg/m2) and males (n = 12, age: 23 ± 3 y, body mass index: 26 ± 4 kg/m2). Subjects were tested at baseline and during the last 5 min of a 15-min RESPeRATE-guided SLOWB session. Overall, SLOWB reduced systolic BP by 3.2 ± 0.8 mmHg (main effect, P < 0.01). Females had lower systolic BP (main effect, P = 0.02); we observed no interaction between sex and SLOWB. SLOWB also reduced muscle sympathetic nerve activity burst incidence by -5.0 ± 1.4 bursts/100 heartbeats (main effect, P < 0.01). Although females tended to have lower burst incidence (main effect, P = 0.1), there was no interaction between sex and SLOWB. Cardiovagal baroreflex sensitivity improved during SLOWB (21.0 vs. 36.0 ms/mmHg, P = 0.03) with no effect of sex. Despite lower overall BP in females, our data support a lack of basement effect on SLOWB-induced reductions in BP, as SLOWB was equally effective in reducing BP in males and females. Our findings support the efficacy of the RESPeRATE device for reducing BP in both sexes, even in young, normotensive individuals.NEW & NOTEWORTHY We provide support for the effectiveness of device-guided slow breathing for blood pressure reduction in young normotensive women and men. Despite having lower baseline blood pressure and sympathetic nerve activity, women experienced equivalent reductions in both measures in response to RESPeRATE-guided slow breathing as men. Thus, slow breathing appears to be effective in young healthy normotensive individuals of both sexes and may be an ideal preventative therapy against future hypertension.

Nitrate-Rich Fruit and Vegetable Supplement Reduces Blood Pressure in Normotensive Healthy Young Males without Significantly Altering Flow-Mediated Vasodilation: A Randomized, Double-Blinded, Controlled Trial.

Nitric oxide (NO) is a primary vasodilatory factor released from endothelial cells of the peripheral vasculature. NO production is stimulated through enzymatic-dependent mechanisms via NO synthase and from dietary intake of nitrate-containing foods or supplements. We evaluated the efficacy of a nitrate-rich fruit and vegetable liquid supplement (FVS, AMPED NOx, Isagenix International LLC) versus a juice low in nitrates (prune juice, PRU) on circulating nitrates/nitrites as well as cardiovascular parameters in 45 healthy normotensive men (18–40 y). Blood pressure, flow-mediated dilation (FMD), and plasma nitrates and nitrites were measured at baseline and after two weeks of supplementation (2 oz/d). Subjects also completed questionnaires on sleep quality and mood since these measures have been associated with endothelial function. In contrast to PRU, FVS significantly increased plasma nitrates and nitrites (+67%, p < 0.001) and decreased diastolic blood pressure (−9%, p=0.029) after two weeks. The change in FMD for FVS supplementation versus PRU supplementation was not significant (+2% vs. −9%, respectively, p=0.145). Changes in sleep quality or total mood state did not differ between groups after the 2-week study. Thus, the nitrate-rich FVS supplement increased plasma NO and reduced diastolic blood pressure in young normotensive men, but increased plasma NO was not associated with improvements in FMD, mood, or sleep. This trial is registered with ClinicalTrials.gov NCT03486145.

Abstract P486: Effects of Isometric Leg Training on Ambulatory Blood Pressure and Morning Blood Pressure Surge in Young Normotensive Men and Women

Introduction: Cardiovascular disease (CVD) is a major cause of death globally with hypertension reported to be a leading modifiable risk factor. Ambulatory blood pressure (BP), in particular diurnal BP variability, is considered to be associated with CVD risk. In addition, the morning BP surge (MBPS) is thought to be associated with increased stroke risk and to be a destabilizing factor for atherosclerotic plaque. Isometric resistance training (IRT) is an effective method of lowering BP and has been recommended by the American Heart Association as an alternative treatment for reducing BP. To date, few studies have investigated the effects of IRT on ambulatory BP and particularly the morning surge in BP. Therefore, the purpose of this study was to determine whether (i) IRT causes reductions in ambulatory BP and the MBPS, in young normotensives and (ii) there are any sex differences in these changes. Methods: Ambulatory BP was measured prior to, and after, 10 weeks of bilateral leg IRT using an isokinetic dynamometer (4 x 2 minute contractions at 20% MVC, with 2 minute rest periods on 3 days per week). Twenty normotensive individuals (10 men, age=21 ± 4 years; 10 women, age=23 ± 5 years) were recruited. A two-way repeated measures ANOVA was used to assess the within and between groups ambulatory (mean 24-h, daytime, night time and diurnal variation) BP and MBPS. MBPS was calculated as: mean systolic BP 2 hours after waking minus the lowest sleeping 1 hour mean systolic BP. Results: There were significant reductions in 24-h ambulatory (4 ± 2 mmHg, p=0.0001; 4 ± 2 mmHg, p=0.0001) systolic BP in both men and women following IRT. This comprised significant reductions in day time (5 ± 5 mmHg, p=0.019; 5 ± 4 mmHg, p=0.002) but not night time (1 ± 5 mmHg, p=0.75; 1 ± 3 mmHg, p=0.3) systolic BP. Additionally, there were significant reductions in the MBPS (6 ± 8 mmHg, p=0.044; 6 ± 7 mmHg, p=0.019). There were no significant differences between men and women in these changes (p&gt;0.05). Conclusion: These results support previous research showing that IRT is effective in lowering ambulatory BP. Furthermore, the significant reductions in the MBPS offer the potential for clinically meaningful CVD and stroke risk reduction, provided these effects can be demonstrated in those who are at risk.

Effect of involved muscle mass in resistance exercise on post exercise blood pressure and rate pressure product

As the blood pressure (BP) and heart rate (HR) response during the recovery period can be influenced by size of activated muscle mass, it is possible that this variable also has some distinct effects on post-exercise rate pressure product (RPP). The aim of the present study was to investigate and compare the systolic (SBP) and diastolic blood pressure (DBP), HR, and RPP responses during recovery to resistance exercise with different body regions.Twelve normotensive young men randomly performed three resistance exercise trials with upper limbs (UL), lower limbs (LL), and whole body (WB), and a control session (CON). All exercise trails included 3 sets of 10 repetitions, with 65% of 1-repetition maximum (1RM) with 2min rest interval between sets and exercises. SBP, DBP, HR, and RPP were measured before and at each 15min after exercise until 60min. Blood lactate (bLAC) was also measured before, and at the 1st minute after the end of exercise. Analysis of variance (ANOVA) and Bonferroni post hoc were used to analyze the data, with a p<.05.The SBP decrease for 60min after UL, LL, and WB exercise trials was similar, whereas there was no change in post-exercise DBP after the trials. Significant increases were observed in RPP for 15min after LL, and 30min after UL and WB. The blood lactate concentration significantly increased after UL, LL and WB resistance exercise when compared to the rest values, as well as in the CON sessions.UL, LL and WB resistance exercise lead to post-exercise hypotension, similar in magnitude and duration, and almost produce the same cardiovascular responses, despite different muscle mass involvement.

Lower skeletal muscle capillarization in hypertensive elderly men

Aging strongly affects the skeletal muscle and is associated with microvascular dysfunctions. Age is also a primary risk factor for the metabolic syndrome, which is a cluster of metabolic and cardiovascular symptoms. Among the metabolic syndrome components, hypertension is the most prevalent in elderly subjects and has a central role in vascular alterations. Despite critical clinical outcomes, the effects of hypertension and metabolic syndrome on skeletal muscle capillarization have poorly been investigated during aging. In the present study, muscle biopsies from normotensive young (YO) and elderly (ELc) men, and elderly men with hypertension (EL-HT) or metabolic syndrome (EL-MS) were assessed for the number of capillaries around a fiber (CAF), capillary-to-fiber perimeter exchange (CFPE), length of contact to perimeter of fiber ratio (LC/PF), capillary tortuosity, and for extracellular matrix (ECM) embedding capillaries. As capillarization and muscle mitochondrial oxidative capacity may be associated, we also investigated cytochrome c oxidase (COX) content. Our findings indicate that capillarization and COX did not change between normotensive adult and old individuals. They further reveal that hypertension in elderly men is associated with reduced CAF (ELc: 5.2±0.4, EL-HT: 4.1±0.2, P<0.02 for type I fibers; ELc: 4.1±0.2, EL-HT: 3.1±0.3, P<0.03 for type IIA fibers), CFPE (ELc: 7.9±0.7, EL-HT: 6.4±0.4 capillaries/1000μm, P<0.03 for type I fibers; ELc: 6.5±0.4, EL-HT: 5.2±0.4 capillaries/1000μm, P<0.03 for type IIA fibers), LC/PF (ELc: 23.3±1.2, EL-HT: 17.8±0.6%, P<0.01 for type I fibers; ELc: 19.8±1.1, EL-HT: 15.6±0.8%, P<0.01 for type IIA fibers) and capillary tortuosity, and with ECM endomysium fibrosis. Capillary rarefaction also correlated with lower COX content in the old hypertensive muscle. No further modification occurred with metabolic syndrome in elderly men. Collectively, our results suggest that hypertension plays a central role in muscle capillarization during aging, and that the other components of metabolic syndrome do not make major additional changes in the aged skeletal muscle capillary network.

Post-exercise hypotension of normotensive young men through track running sessions

INTRODUCTION: After a single session of physical exercise the blood pressure is reduced (post-exercise hypotension, PHE) and it has been considered as a non-pharmacological mechanism to control the blood pressure. When the exercise is performed since youth it can prevent or avoid hypertension. However, it is important to consider studies with clear practical applications to optimize its reproducibility on a daily basis. OBJECTIVE: Analyze the PEH of normotensive and physically active young men after two track running sessions (maximum and submaximal). METHODS: Participated in this study 62 physically active young men (23.3 ± 4.2 years old; 75.5 ± 9.8 kg; 177.7 ± 5.5 cm; 12.0 ± 4.6% body fatF; 52.4 ± 4.0 mL.kg-1.min-1oxygen uptake), which performed a maximum laboratory exercise test for determination of maximal oxygen uptake (VO2max - aerobic power) and subsequently three randomly running sessions (maximum - T1600; submaximal - T20; control - CON), with 48h interval between themselves. Blood pressure (BP) was measured each 15min during a 60 min period after sessions. RESULTS: Both the maximum and the submaximal exercise lead to PEH. The post-exercise values of systolic blood pressure and diastolic blood pressure differed from resting value in session T20 (p&lt;0.05). The same pattern occurred after T1600 (p&lt;0.05), evidenced from 30th minute post-exercise. The CON did not result in PEH. The magnitude of decay for the mean BP at the 45th after maximum exercise was higher than the other sessions (p&lt;0.05). CONCLUSION: We concluded that both maximum and submaximal exercises, performed on a track running condition, caused PEH in young normotensive and physically active men.

Dietary sodium influences the effect of mental stress on heart rate variability

Dietary sodium influences intermediate physiological traits in healthy adults independent of changes in blood pressure. The purpose of this study was to test the hypothesis that dietary sodium affects cardiac autonomic modulation during mental stress. In a prospective, randomized cross-over design separated by 1 month between diets, 70 normotensive healthy young adults (F/M: 44/26, aged 18-38 years) consumed a 5-day low (10 mmol/day), normal (150 mmol), and high (400 mmol) sodium diet followed by heart rate variability (HRV) recordings at rest and during 5-min computerized mental arithmetic. Women were studied in the low hormone phase of the menstrual cycle following each diet. Diet did not affect resting blood pressure, but heart rate (HR) (mean ± SE) was 66 ± 1, 64 ± 1, and 63 ± 1 bpm in low, normal, and high sodium conditions, respectively (analysis of variance P = 0.02). For HRV, there was a main effect of sodium on resting SD of normalized RR intervals (SDNN), square root of the mean squared difference of successive normalized RR intervals (RMSSD), high frequency, low-frequency normalized units (LFnu), and high-frequency normalized units (HFnu) (P < 0.01 for all). The response to low sodium was most marked and consistent with sympathetic activation and reduced vagal activity, with increased LFnu and decreased SDNN, RMSSD, and HFnu compared to both normal and high sodium conditions (P ≤0.05 for all). Dietary sodium-by-mental stress interactions were significant for mean NN, RMSSD, high-frequency power, LFnu, and low frequency/high frequency ratio (P < 0.05 for all). The interactions signify that sodium restriction evoked an increase in resting sympathetic activity and reduced vagal activity to the extent that mental stress caused modest additional disruptions in autonomic balance. Conversely, normal and high sodium evoked a reduction in resting sympathetic activity and incremental increase in resting vagal activity, which were disrupted to a greater extent during mental stress compared to low sodium. We conclude that autonomic control of HRV at rest and during mental stress is altered by dietary sodium in healthy normotensive young adult men and women.

Post-exercise blood pressure responses to different resistive training modalities

The purpose of the present study was to evaluate the post-exercise blood pressure and heart rate responses to two different methods of resistance exercise [traditional (TR) and standard (ST)] based on differences in contraction times. Thirty-five normotensive young men (20.6 ± 1.7 years; 71.0 ± 2.7 kg; 175.7 ± 5.3 cm) participated in this study. The volunteers were randomly assigned into three groups: non-exercised control group (n = 10), TR group (n = 13) and ST group (n = 12). The TR group performed resistance exercise with 2 s eccentric and 4 s concentric contractions. In contrast, contraction times were 1 s eccentric and 2 s concentric for the ST group. The exercises were performed in three sets × eight repetitions at 80 % of 1RM. Blood pressure and heart rate were measured before exercise (baseline) and at intervals of 10 min for 90 min after exercise. During control trial, blood pressure and heart rate did not change significantly. Post-exercise blood pressure did not change after resistance exercise method (TR or ST) compared to pre-exercise levels. Heart rate was increased similarly after exercise for both exercised groups in all post-exercise measurements compared with baseline. Resistance exercise at TR or ST methods in normotensive men did not influence the post-exercise blood pressure levels and heart rate response. However, blood pressure and heart rate levels were lower in some time points after ST than TR exercise bouts.

Arterial baroreflex control of sympathetic nerve activity during acute hypotension is enhanced in young normotensive black men

Although impairments in arterial baroreflex (ABR) control of heart rate have been reported in black compared to white subjects, no studies have examined the potential for racial differences in the ABR control of muscle sympathetic nerve activity (MSNA). Therefore, we tested the hypothesis that ABR control of MSNA is impaired in young black men compared to white men. In 12 non‐hypertensive men (7 black and 5 white, age 18–27 yr) ABR control of MSNA was determined using 100μg i.v. of sodium nitroprusside (NTP) followed 1 min later by 150μg of phenylephrine (PE) during supine rest (3 trials/subject). The slope of the relationship (i.e., gain) between changes in diastolic blood pressure and MSNA was determined. Overall sympathetic baroreflex gain was not different between racial groups (blacks: − 1.9±0.2 vs. whites: −2.4 ± 0.4 AU·beat·mmHg−1, p&gt;;0.05). Similarly, sympathetic baroreflex gain for hypertension (PE phase) was also not different between groups (blacks: −1.9±0.3 vs. whites: −1.7±0.2 AU·beat·mmHg−1, p&gt;;0.05). However, sympathetic baroreflex gain for hypotension (NTP phase) was significantly elevated in blacks (−4.0±0.3) compared to whites (−3.2±0.1 AU·beat·mmHg−1, p&lt;0.05). In contrast to our hypothesis, these preliminary findings suggest that ABR control of MSNA is similar or enhanced in young blacks compared to their white counterparts.Supported by NIH Grant R15HL096103 (DMK) and RO1 HL093167 (PJF)