Vascular Adaptation to Exercise in Humans: Role of Hemodynamic Stimuli

Acute partial sleep deprivation and high-intensity interval exercise effects on postprandial endothelial function

PURPOSE

Acute-total and chronic-partial sleep deprivation increase the risks for cardiovascular disease (CVD). Cardiovascular function assessed by flow mediated dilation (FMD) is reduced after sleep deprivation. High-intensity interval exercise (HIIE) improves postprandial FMD. Sleep-deprived individuals may practice HIIE followed by a high-fat breakfast. This study investigated the acute-partial sleep deprivation (APSD) and HIIE interaction on postprandial FMD.

METHODS

Fifteen healthy males (age 31 ± 5 years) participated in: (a) reference sleep (~ 9.5 h) with no HIIE (RS), (b) RS and HIIE (RSX), and (c) APSD and HIIE (SSX). HIIE was performed in 3:2 min intervals at 90% and 40% of VO₂ reserve. FMD was assessed the night before (D1), the morning of the next day (D2), 1 h (1hrPE) and 4 h post HIIE (4hrPE).

RESULTS

FMD% change was lower at RS compared to both RSX (F_1,14 = 23.96, p < 0.001, η² = 0.631) and SSX (F_1,14 = 4.8, p = 0.47, η² = 0.253) at 1hrPE. RSX and SSX did not differ at 1hrPE (F_1,14 = 0.2, p = 0.889, η² = 0.001), but SSX elicited greater FDM responses. Absolute FMD change was lower at RS compared to both RSX (F_1,14 = 21.5, p < 0.001, η² = 0.606) and SSX (F_1,14 = 7.01, p = 0.019, η² = 0.336) at 1hrPE. RSX and SSX did not differ at 1hrPE (F_1,14 = .03, p = 0.858, η² = 0.002), but SSX elicited greater FDM responses.

CONCLUSIONS

HIIE short-term effects on cardiovascular function remain cardioprotective even after an acute-partial sleep deprivation.

Can Active Aerobic Exercise Reduce the Risk of Cardiovascular Disease in Prehypertensive Elderly Women by Improving HDL Cholesterol and Inflammatory Markers?

This study aims to verify the efficacy of exercise programs designed to prevent and treat hypertension-induced cardiovascular disease (CVD) by analyzing the effects of a 6-month active aerobic exercise program, administered to prehypertensive elderly women, on reducing the risk of developing CVD by enhancing their physical fitness level and improving the detailed markers of high-density lipoprotein cholesterol (HDL-C) and inflammatory markers. We assigned the elderly women (≥65 years) recruited into normal blood pressure (120–129/80–84; NBP, n = 18) and high-normal blood pressure (130–139/85–89; HNBP, n = 12) groups according to the European guidelines for the management of arterial hypertension. The exercise program was made up of combined workouts of elastic band resistance exercise and aerobics with dance music. The program took place three times a week for six months, with each session lasting 60 min. We measured pre- and post-intervention body composition, blood pressure, physical fitness level, blood lipids profile, HDL-C, SAA, TNF-α, IL-6, IL-4, IL-15, CRP, and HSP70 and calculated the Framingham risk scores for comparison. A significant post-intervention reduction in the mean systolic blood pressure (SBP) was observed in the HNBP group (p < 0.001), with significant increase in HDL-C (p < 0.01) and significant decrease in serum amyloid A (SAA) concentration (p < 0.01). A significant improvement in physical fitness factors such as physical efficiency index (PEI) was also observed in the HNBP group (p < 0.05). The post-intervention TNF-α, IL-6, and SAA concentrations were more significantly lower in the HNBP than in the NBP group (p < 0.05). Compared to the baseline values, a significant decrease in SAA concentration (p < 0.01) and significant increase in HSP70 concentration (p < 0.001) were observed in the HNBP group. The HNBP group’s 10-year CVD risk was also significantly reduced (p < 0.05). The pre–post differences in SBP and DBP were significantly correlated with those in the anti-inflammatory markers IL-4 and IL-15 (p < 0.01). In conclusion, the 6-month active aerobic exercise program of moderate intensity administered to prehypertensive elderly women (≥65 years) had the effect of reducing the 10-year CVD risk through a substantial reduction in SBP, overall physical fitness improvement, increase in HDL-C, decrease in SAA concentration, and substantial decrease in inflammatory biomarkers. It was also confirmed that an increase in anti-inflammatory markers, which showed a small range of increase with respect to the decrease in blood pressure, may have a major effect.

Maintenance of endothelial function following acute resistance exercise in females is associated with a tempered blood pressure response

Acute resistance exercise-induced hypertensive stimulus impairs endothelial function in males. Because prior work indicates that female subjects have a tempered blood pressure response to acute resistance exercise, we hypothesized that, compared with males, females would better maintain endothelial function following resistance exercise and that this preservation would be associated with a lower hypertensive stimulus. Twenty-nine young healthy males (n = 16) and females (n = 13) participated in this study. All subjects performed a session of resistance exercise (leg extension) at the same relative workload [65% of one repetition maximum (1RM)]. The blood pressure response to exercise was characterized, and brachial artery flow-mediated dilation (FMD) was measured before and after. Males performed a second experimental trial in which the blood pressure response to resistance exercise was matched to that of females. This was accomplished by reducing the workload (~25% of 1RM). When resistance exercise was performed at the same relative workload, the systolic blood pressure was greater in males compared with females. Congruently, resistance exercise caused a significant impairment in FMD in males but not in females (P < 0.001). When the exercise workload was reduced in males, they no longer displayed an impairment in FMD following resistance exercise and, as such, the sex difference was abolished (P > 0.05). The present study reveals that acute resistance exercise transiently impairs endothelial function in young, healthy males but not in age-matched females. Notably, the maintenance of endothelial function in females is associated with a lower blood pressure response during resistance exercise.NEW & NOTEWORTHY The present data demonstrate for the first time that acute resistance exercise impairs endothelial function in young, healthy male but not female subjects. In addition, we show that the preservation of endothelial function in females is associated with a mitigated blood pressure response during resistance exercise. Accordingly, this work portrays a sexual dimorphism in the barostress response, and ensuing vascular effects, to resistance exercise.

The Efficacy of Stretching Exercises on Arterial Stiffness in Middle-Aged and Older Adults: A Meta-Analysis of Randomized and Non-Randomized Controlled Trials

Background: Aerobic exercise is known to reduce arterial stiffness; however, high-intensity resistance exercise is associated with increased arterial stiffness. Stretching exercises are another exercise modality, and their effect on arterial stiffness remains unclear. The purpose of this study was to determine whether stretching exercises reduce arterial stiffness in middle-aged and older adults, performing the first meta-analysis of currently available studies. Methods: We searched the literature for randomized controlled trials (RCTs) and non-RCTs published up to January 2020 describing middle-aged and older adults who participated in a stretching intervention vs. controls without exercise training. The primary and secondary outcomes were changes in arterial stiffness and vascular endothelial function and hemodynamic status. Pooled mean differences (MDs) and standard MDs (SMDs) with 95% confidence intervals (CIs) between the intervention and control groups were calculated using a random effects model. Results: We identified 69 trials and, after an assessment of relevance, eight trials, including a combined total of 213 subjects, were analyzed. Muscle stretching exercises were shown to significantly reduce arterial stiffness and improve vascular endothelial function (SMD: −1.00, 95% CI: −1.57 to −0.44, p = 0.0004; SMD: 1.15, 95% CI: 0.26 to 2.03, p = 0.01, respectively). Resting heart rate (HR) and diastolic blood pressure (DBP) decreased significantly after stretching exercise intervention (MD: −0.95 beats/min, 95% CI: −1.67 to −0.23 beats/min, p = 0.009; MD: −2.72 mm Hg, 95% CI: −4.01 to −1.43 mm Hg, p < 0.0001, respectively) Conclusions: Our analyses suggest that stretching exercises reduce arterial stiffness, HR, and DBP, and improve vascular endothelial function in middle-aged and older adults.

Cardiac Rehabilitation and Endothelial Function

Endothelial dysfunction is an early abnormality in the process of atherosclerosis and cardiovascular disease and has been associated with worse clinical outcome. Cardiac rehabilitation (CR) has been reported to be helpful to reduce cardiovascular events in various types of cardiac disease, but the mechanisms of its beneficial effects remain only partially known. In this article, we review the studies that assessed the effect of CR on endothelial function in patients with various cardiac conditions. Available data show that CR significantly improves impaired endothelial function in these patients, which may contribute to the beneficial effects of CR on clinical outcome.

Exercise-induced elevations in cerebral blood velocity are greater in running compared to cycling at higher intensities

The optimal exercise intensity and modality for maximizing cerebral blood flow (CBF) and hence potential exposure to positive, hemodynamically derived cerebral adaptations is yet to be fully determined. This study compared CBF velocity responses between running and cycling across a range of exercise intensities. Twenty-six participants (12 females; age: 26 ± 8 years) completed four exercise sessions; two mode-specific maximal oxygen consumption (VO2max ) tests, followed by (order randomized) two incremental exercise protocols (3-min stages at 35%, 50%, 65%, 80%, 95% VO2max ). Continuous measures of middle cerebral artery velocity (MCAv), oxygen consumption, end-tidal CO2 (PET CO2 ), and heart rate were obtained. Modality-specific MCAv changes were observed for the whole group (interaction effect: p = .01). Exercise-induced increases in MCAvmean during cycling followed an inverted-U pattern, peaking at 65% VO2max (Δ12 ± 7 cm/s from rest), whereas MCAvmean during running increased linearly up to 95% VO2max (change from rest: Δ12 ± 13 vs. Δ7 ± 8 cm/s for running vs. cycling at 95% VO2max ; p = .01). In contrast, both modalities had an inverted-U pattern for PET CO2 changes, although peaked at different intensities (running: 50% VO2max , Δ6 ± 2 mmHg; cycling: 65% VO2max , Δ7 ± 2 mmHg; interaction effect: p = .01). Further subgroup analysis revealed that the running-specific linear MCAvmean response was fitness dependent (Fitness*modality*intensity interaction effect: p = .04). Above 65% VO2max , fitter participants (n = 16; male > 45 mL/min/kg and female > 40 mL/min/kg) increased MCAvmean up to 95% VO2max , whereas in unfit participants (n = 7, male < mL/min/kg and female < 35 mL/min/kg) MCAvmean returned toward resting values. Findings demonstrate that modality- and fitness-specific profiles for MCAvmean are seen at exercise intensities exceeding 65% VO2max .

Chronic swimming training resulted in more relaxed coronary arterioles in male and enhanced vasoconstrictor ability in female rats

BACKGROUND

Exercise training is associated with hypertrophy of left ventricle (LV). The aim of the present study is to evaluate sex differences in the adaptation of the coronary contractile function in physiological left ventricular hypertrophy induced by long-term swim training.

METHODS

Thirty-two Wistar rats were randomly divided into 4 groups: exercised male (ExM), exercised female (ExF), untrained control male (CoM), and untrained control female (CoF). The trained animals underwent a 12-week-long swim training program. After finishing the training program, LV morphology and function were checked by echocardiography. The spontaneous tone, thromboxane (TxA<inf>2</inf>) agonist-induced vascular contractility and non-endothelial dilatation of the isolated intramural coronary resistance artery were examined by pressure microangiometry. The thromboxane receptor (TxA<inf>2</inf>R) protein expression in the wall of coronary arteries was examined using immunohistochemistry.

RESULTS

The LV mass index was significantly higher in the ExM and ExF groups, furthermore the LV mass index was significantly higher in female than in male animals. ExM animals had lower spontaneous tone than ExF. TxA<inf>2</inf> agonist-induced tone was raised only in ExF animals. The resistance coronary artery of exercised male animals had a significantly lower level of TxA<inf>2</inf>R positivity compared to exercised females.

CONCLUSIONS

Both sexes broaden their range of contractility following chronic swimming, but the vessel tone shifted toward contraction in exercised female rats, while these values shifted toward relaxation in males. These observations underline the significance of identifying potential gender differences in the chronic exercise-induced coronary vascular remodeling in human athletes.

Sex-specific alterations in blood-borne factors in physically inactive individuals are detrimental to endothelial cell functions

Mechanisms underlying the protective effects of both habitual endurance exercise and the female sex on vascular function are incompletely understood. Blood-borne circulating factors, such as circulating microRNAs (ci-miRs), may partially explain these effects. Blood samples were obtained from young, healthy men and women who either habitually performed endurance exercise (endurance trained) or were relatively inactive (sedentary). Women were tested during the early follicular phase of the menstrual cycle or the placebo pill phase of oral contraceptive to control for estrogen. Cultured human umbilical vein endothelial cells (HUVECs) were exposed to participants' serum in migration, proliferation, and reactive oxygen species (ROS) assays. Real-time quantitative polymerase chain reaction was used to quantify an initial array of 84 cardiovascular disease (CVD)-related ci-miRs, followed by validation of 10 ci-miRs. All participants were devoid of traditional CVD risk factors, and circulating estradiol concentration was not different between groups. Serum of endurance-trained women induced greater HUVEC migration compared with serum of sedentary women. HUVEC ROS production was greater in response to serum of sedentary men compared with serum of endurance-trained men and sedentary women. There were sex effects on the levels of nine ci-miRs, with greater levels in men, while ci-miRs-140-5p and 145-5p were also higher in sedentary compared with endurance-trained men and/or women. In a sex-specific manner, habitual endurance exercise was associated with beneficial effects of serum on HUVECs. Thus, alterations in circulating factors may contribute to the protective effects of habitual endurance exercise on vascular health. Additionally, sex had a greater impact than habitual activity level on the levels of vascular-related ci-miRs.NEW & NOTEWORTHY Serum from sedentary women caused impaired endothelial migration, whereas serum from sedentary men elicited increased endothelial reactive oxygen species production as compared with serum from their endurance-trained counterparts. Select CVD-related circulating microRNAs (ci-miRs) were higher in men than women, while ci-miRs-140-5p and 145-5p were also higher in sedentary versus trained men and/or women. Our data suggest that alterations in circulating factors may contribute to the protective effects of habitual exercise and sex on vascular health.

Isometric Versus Aerobic Training Effects on Vascular Adaptation in Patients with Type 2 Diabetes

BACKGROUND AND OBJECTIVE

Diabetes is known to be associated with arterial remodeling and dysfunction which predispose to different microvascular complications. This study was aimed to find out the effect of isometric versus aerobic training on vascular adaptation in patients with type 2 diabetes.

MATERIALS AND METHODS

The study was carried out on 40 type 2 diabetic patients (20 men and 20 women). Patients were selected from the outpatient clinic of El-Agouza Police Authority Hospital. They were assigned into 2 matched and equal groups in number. Group A with mean age of 49.55 years, received unilateral isometric handgrip exercise 22 min per session, 3 sessions per week for 8 weeks and group B with mean age 50.15 years, received aerobic exercise in form of arm ergometry for 30 min, 3 sessions per week for 8 weeks. They were assessed by a Doppler ultrasound for brachial artery adaptation (the brachial artery diameter, blood velocity and shear rate) before and after 8 weeks of training.

RESULTS

Group A showed significant improvement in brachial artery adaptation as increased brachial artery diameter from 4.28±0.19 to 4.43±0.18, baseline vessel velocity from 7.09±0.41 to 8.62±0.46 and its shear rate from 66.24±4.19 to 77.65±5.27, while in group B who received the aerobic exercise the results showed a minimal change between pre training and post-training results 4.24±0.23 to 4.26±0.21 for brachial artery diameter, 7.26±0.54 to 7.46±0.67 for blood velocity and 67.8±3.16 to 68.81±4.29 for shear rate respectively.

CONCLUSION

Isometric handgrip exercise improved brachial artery diameter, blood velocity and shear rate in patients with type 2 diabetes.

The role of exercise in the management of adverse effects of androgen deprivation therapy for prostate cancer: a rapid review

PURPOSE

Prostate cancer (PCa) is the most commonly diagnosed cancer in Australia, accounting for one quarter of all new cancer diagnoses for males. Androgen deprivation therapy (ADT) is the standard first-line therapy for metastatic PCa but is also used across much of the spectrum of disease. Unfortunately, debilitating adverse effects are a significant and largely unavoidable feature of ADT. A recent systematic review of adverse effects of ADT identified 19 sub-groups classified according to the Common Terminology Criteria for Adverse Events (CTCAE) Version 5.0. The potential for multiple simultaneous adverse effects, their associated management and the impact of adverse effects on cancer outcomes and quality of life are important considerations in the treatment and supportive care of men with PCa. Exercise is increasingly being recognized as an efficacious strategy in managing these adverse effects.

METHODS

A rapid review was undertaken to examine the role of exercise in the management of the most commonly reported ADT adverse effects classified according to the CTCAE sub-groups. A systematic search was conducted in Medline, PsycINFO, Google Scholar and Google for the years 2010 to September 2019 to identify the benefits of exercise in managing the adverse effects of ADT for PCa.

RESULTS

There is strong evidence for exercise as medicine in addressing several of the adverse effects of PCa such as loss of muscle mass and strength, fatigue and declining physical function. Moderate level evidence for PCa exists for exercise-induced improvements in depression and anxiety, bone loss, and sexual dysfunction. While evidence of the effectiveness of exercise is lacking for many adverse effects of ADT for PCa, evidence in the cancer population as a whole or other clinical populations is strong, and many clinical guidelines recommend exercise as a fundamental part of their clinical management. With the exception of gynaecomastia and breast pain, there is increasing evidence (PCa, cancer or other clinical populations) to suggest that exercise has the potential to reduce and even prevent many of the adverse effects of ADT, thus improving survivorship outcomes for men with PCa.

CONCLUSION

Exercise has the potential to reduce and even prevent many of the adverse effects of ADT, thus improving survivorship outcomes for men with PCa. The use of exercise for PCa management has the potential to translate into health and economic benefits in improved quality of life and fewer complications, resulting in savings to the health care system, enhanced productivity and reduced patient and carer burden. Exercise thus has the potential to improve quality of life for this population as well as generate significant cost savings.

Impact of interval walking training managed through smart mobile devices on albuminuria and leptin/adiponectin ratio in patients with type 2 diabetes

Background

Interval walking training has demonstrated more pronounced positive effects on physical fitness and metabolism in type 2 diabetes (T2D), compared to continuous walking. One of the pathogenic mechanisms of T2D is associated with derangements in leptin/adiponectin axis, which might predispose affected individuals to vascular inflammation and albuminuria. The aim of this study was to investigate the effects of interval walking training delivered through smart mobile devices upon albuminuria and leptin/adiponectin ratio in patients with T2D.

Methods

Patients with T2D aged 35–75 were randomized into control (n = 26) and interval training (IT, n = 14) groups. Patients in IT group had to perform three 60‐min interval walking sessions (3 min intervals of slow and fast walking with the intensity of 40% and 70% of the peak energy expenditure) per week delivered by smartphone application for four months. The adherence to training was monitored remotely. Outcome measures were albuminuria, leptin/adiponectin ratio, obesity indicators, and glycaemic control. Leptin and adiponectin concentration was measured in serum samples by Luminex technology.

Results

In the IT group compared to control group, we observed a statistically significant decrease in albuminuria (p = .002) and leptin/adiponectin ratio (p = .01), as well as a decrease in HbA1c close to statistical significance (p = .09). In IT group, changes in leptin/adiponectin ratio correlated significantly with changes in hip circumference (p = .024).

Conclusion

Interval walking training is beneficial for vascular health in T2D via impact on albuminuria and leptin/adiponectin ratio.

Exercise modulation of tumour perfusion and hypoxia to improve radiotherapy response in prostate cancer

Background

An increasing number of studies indicate that exercise plays an important role in the overall care of prostate cancer (PCa) patients before, during and after treatment. Historically, research has focused on exercise as a modulator of physical function, psychosocial well-being as well as a countermeasure to cancer- and treatment-related adverse effects. However, recent studies reveal that exercise may also directly influence tumour physiology that could beneficially affect the response to radiotherapy.

Methods

In this narrative review, we provide an overview of tumour vascular characteristics that limit the effect of radiation and establish a rationale for exercise as adjunct therapy during PCa radiotherapy. Further, we summarise the existing literature on exercise as a modulator of tumour perfusion and hypoxia and outline potential future research directions.

Results

Preclinical research has shown that exercise can reduce intratumoral hypoxia—a major limiting factor in radiotherapy—by improving tumour perfusion and vascularisation. In addition, preliminary evidence suggests that exercise training can improve radiotherapy treatment outcomes by increasing natural killer cell infiltration in a murine PCa model.

Conclusions

Exercise is a potentially promising adjunct therapy for men with PCa undergoing radiotherapy that may increase its effectiveness. However, exercise-induced tumour radiosensitisation remains to be confirmed in preclinical and clinical trials, as does the optimal exercise prescription to elicit such effects.

Skeletal muscle microvascular insulin resistance in type 2 diabetes is not improved by eight weeks of regular walking

We aimed to examine whether individuals with type 2 diabetes (T2D) exhibit suppressed leg vascular conductance and skeletal muscle capillary perfusion in response to a hyperinsulinemic-euglycemic clamp and to test whether these two variables are positively correlated. Subsequently, we examined whether T2D-associated skeletal muscle microvascular insulin resistance, as well as overall vascular dysfunction, would be ameliorated by an 8-wk walking intervention (45 min at 60% of heart rate reserve, 5 sessions/week). We report that, relative to healthy subjects, overweight and obese individuals with T2D exhibit depressed insulin-stimulated increases in leg vascular conductance, skeletal muscle capillary perfusion, and Akt phosphorylation. Notably, we found that within individuals with T2D, those with lesser increases in leg vascular conductance in response to insulin exhibited the lowest increases in muscle capillary perfusion, suggesting that limited muscle capillary perfusion may be, in part, linked to the impaired ability of the upstream resistance vessels to dilate in response to insulin. Furthermore, we show that the 8-wk walking intervention, which did not evoke weight loss, was insufficient to ameliorate skeletal muscle microvascular insulin resistance in previously sedentary, overweight/obese subjects with T2D, despite high adherence and tolerance. However, the walking intervention did improve (P < 0.05) popliteal artery flow-mediated dilation (+4.52%) and reduced HbA1c (-0.75%). It is possible that physical activity interventions that are longer in duration, engage large muscle groups with recruitment of the maximum number of muscle fibers, and lead to a robust reduction in metabolic risk factors may be required to overhaul microvascular insulin resistance in T2D.NEW & NOTEWORTHY This report provides evidence that in sedentary subjects with type 2 diabetes diminished insulin-stimulated increases in leg vascular conductance and ensuing blunted capillary perfusion in skeletal muscle are not restorable by increased walking alone. More innovative physical activity interventions that ultimately result in a robust mitigation of metabolic risk factors may be vital for reestablishing skeletal muscle microvascular insulin sensitivity in type 2 diabetes.

Evidence for improved systemic and local vascular function after long-term passive static stretching training of the musculoskeletal system

KEY POINTS

Vascular function and arterial stiffness are important markers of cardiovascular health and cardiovascular co-morbidity. Transitional phases of hypoemia and hypermia, with consequent fluctuations in shear rate, occuring during repetitive passive stretching adminstration (passive stretching training) may constitute an effective stimulus to induce an amelioration in vascular function, arterial stiffness and vascular remodelling by improving central and local blood flow control mechanisms. Vascular function, arterial stiffness and vascular remodelling were evaluated before and after 12 weeks of passive stretching training and after 6 weeks from training cessation, in the femoral, popliteal (treated with stretching), and brachial arteries (untreated) of both sides. After passive stretching training, vascular function and arterial remodelling improved, and arterial stiffness decreased in all the arteries, suggesting modifications of both central and local blood flow control mechanisms. Passive stretching-induced improvements related to central mechanisms seemed to have a short duration, as they returned to pre-training baseline within 6 weeks from training cessation, whereas those more related to a local mechanism persisted in the follow-up.

ABSTRACT

Acute passive stretching (PS) effects on blood flow ( Q ̇ ), shear rate ( Y ̇ ), and vascular function in the feeding arteries of the stretched muscle have been extensively investigated; however, few data are available on vascular adjustments induced by long-term PS training. We investigated the effects of PS training on vascular function and stiffness of the involved (femoral and popliteal) and uninvolved (brachial) arteries. Our hypothesis was that PS-induced changes in Q ̇ and Y ̇ would improve central and local mechanisms of Q ̇ control. Thirty-nine participants were randomly assigned to bilateral PS (n = 14), monolateral PS (n = 13) or no PS training (n = 12). Vascular function was measured before and after 12 weeks of knee extensor and plantar flexor muscles' PS training by single passive limb movement and flow-mediated dilatation (FMD). Central (carotid-femoral artery PWV, PWV_CF ) and peripheral (carotid-radial artery PWV, PWV_CR ) arterial stiffness was measured by pulse-wave velocity (PWV), together with systolic (SBP) and diastolic (DBP) blood pressure. After PS training, increases of 30%, 25% and 8% (P < 0.05) in femoral Δ Q ̇ , popliteal and brachial artery FMD%, respectively, occurred in both PS training groups. A decrease in PWV_CF , PWV_CR , SBP and DBP (-25%, -17%, -4% and -8%, respectively; P < 0.05) was noted. No changes occurred in controls. Vascular function improved and arterial stiffness reduced in the arteries involved and uninvolved with PS training, suggesting modifications in both central and local Q ̇ control mechanisms. PS-induced improvements had a short duration in some of vascular function parameters, as they returned to baseline within 6 weeks of PS training cessation.

Effects of Unilateral Arm Warming or Cooling on the Modulation of Brachial Artery Shear Stress and Endothelial Function during Leg Exercise in Humans

Aim: We examined the effect of modulating the shear stress (SS) profile using forearm warming and cooling on subsequent endothelial function in the brachial artery (BA) during exercise.

Methods: Twelve healthy young subjects immersed their right forearm in water (15°C or 42°C) during a leg cycling exercise at 120–130 bpm for 60 min. The same exercise without water immersion served as a control. The BA diameter and blood velocity were simultaneously recorded using Doppler ultrasonography to evaluate the antegrade, retrograde, and mean shear rates (SRs, an estimate of SS) before, during, and after exercise. The endothelial function in the right BA was evaluated using flow-mediated dilation (FMD) (%) using two-dimensional high-resolution ultrasonography before (baseline) and 15 and 60 min after exercise.

Results: During exercise, compared with the control trial, higher antegrade and mean SRs and lower retrograde SRs were observed in the warm trial; conversely, lower antegrade and mean SRs and higher retrograde SRs were observed in the cool trial. At 15 min postexercise, no significant change was observed in the FMD from baseline in the warm (Δ%FMD: +1.6%, tendency to increase; p = 0.08) and control trials (Δ %FMD: +1.1%). However, in the cool trial, the postexercise FMD at 60 min decreased from baseline (Δ%FMD: −2.7%) and was lower than that of the warm (Δ%FMD: +1.5%) and control (Δ%FMD: +1.2%) trials. Accumulated changes in each SR during and after exercise were significantly correlated with postexercise FMD changes.

Conclusion: Modulation of shear profiles in the BA during exercise appears to be associated with subsequent endothelial function.

The influence of habitual endurance exercise on carotid artery strain and strain rate in young and middle-aged men

NEW FINDINGS

What is the central question of this study? Carotid artery peak circumferential strain (PCS) and strain rate attenuate with age, but appear to be modulated by cardiorespiratory fitness status in young males. However, the relationship between habitual endurance exercise (running) and these parameters has not been studied in young and middle-aged men. What is the main finding and its importance? Young and middle-aged runners exhibited elevated PCS and systolic strain rate (S-SR) compared with non-runners, but habitual running did not influence diastolic strain rate (D-SR). Habitual exercise is associated with comparable improvements in carotid strain parameters in young and middle-aged men, but the age-related decline in PCS and S-SR might be more amenable to habitual endurance exercise than D-SR.

ABSTRACT

Central arterial stiffness is an independent predictor of cardiovascular risk that can be modified by exercise training. However, conventional local measures of carotid artery stiffness display conflicting responses to habitual endurance exercise in young and older adults. Two-dimensional (2D)-Strain imaging of the common carotid artery (CCA) quantifies circumferential deformation (strain) of the arterial wall across the cardiac cycle, which is more sensitive at detecting age-related alterations in CCA stiffness than conventional methods. Therefore, the study was designed to examine the relationship between habitual endurance exercise (running) and CCA 2D-Strain parameters in young and middle-aged men. Short-axis ultrasound images of the CCA were obtained from 13 young non-runners [23 years of age (95% confidence interval: 21, 26 years of age)], 19 young runners [24 (22, 26) years of age], 13 middle-aged non-runners [54 (52, 56) years of age] and 19 middle-aged runners [56 (54, 58) years of age]. Images were analysed for peak circumferential strain (PCS; magnitude of deformation) and systolic and diastolic strain rates (S-SR and D-SR; deformation velocity), and group differences were examined via two-way ANOVA. PCS, S-SR and D-SR were attenuated in middle-aged men compared with young men (all P ≤ 0.001). PCS and S-SR were elevated in young and middle-aged runners when compared with non-runners (P = 0.002 and P = 0.009, respectively), but no age × training status interaction was observed. In contrast, there was no influence of habitual running on D-SR. Habitual exercise is associated with comparable improvements in CCA 2D-Strain parameters in young and middle-aged men, but the age-related decline in PCS and S-SR might be more amenable to habitual endurance exercise than D-SR.

HIITing the brain with exercise: mechanisms, consequences and practical recommendations

The increasing number of older adults has seen a corresponding growth in those affected by neurovascular diseases, including stroke and dementia. Since cures are currently unavailable, major efforts in improving brain health need to focus on prevention, with emphasis on modifiable risk factors such as promoting physical activity. Moderate-intensity continuous training (MICT) paradigms have been shown to confer vascular benefits translating into improved musculoskeletal, cardiopulmonary and cerebrovascular function. However, the time commitment associated with MICT is a potential barrier to participation, and high-intensity interval training (HIIT) has since emerged as a more time-efficient mode of exercise that can promote similar if not indeed superior improvements in cardiorespiratory fitness for a given training volume and further promote vascular adaptation. However, randomised controlled trials (RCTs) investigating the impact of HIIT on the brain are surprisingly limited. The present review outlines how the HIIT paradigm has evolved from a historical perspective and describes the established physiological changes including its mechanistic bases. Given the dearth of RCTs, the vascular benefits of MICT are discussed with a focus on the translational neuroprotective benefits including their mechanistic bases that could be further potentiated through HIIT. Safety implications are highlighted and components of an optimal HIIT intervention are discussed including practical recommendations. Finally, statistical effect sizes have been calculated to allow prospective research to be appropriately powered and optimise the potential for detecting treatment effects. Future RCTs that focus on the potential clinical benefits of HIIT are encouraged given the prevalence of cognitive decline in an ever-ageing population.

Extracellular vesicle species differentially affect endothelial cell functions and differentially respond to exercise training in patients with chronic coronary syndromes

BACKGROUND

Extracellular vesicles are released upon cellular activation and mediate inter-cellular communication. Individual species of extracellular vesicles might have divergent roles in vascular homeostasis and may show different responses to therapies such as exercise training.

AIMS

We examine endothelial effects of medium-size and small extracellular vesicles from the same individual with or without chronic coronary syndrome, and in chronic coronary syndrome patients participating in a four-week high-intensity interval training intervention.

METHODS

Human aortic endothelial cells were exposed to medium-size extracellular vesicles and small extracellular vesicles isolated from plasma samples of study participants. Endothelial cell survival, activation and re-endothelialisation capacity were assessed by respective staining protocols. Extracellular vesicles were quantified by nanoparticle tracking analysis and flow cytometry. Extracellular vesicle microRNA expression was quantified by realtime-quantitative polymerase chain reaction.

RESULTS

In patients with chronic coronary syndrome (n = 25), plasma counts of leukocyte-derived medium-size extracellular vesicles were higher than in age-matched healthy controls (n = 25; p = 0.04) and were reduced by high-intensity interval training (n = 15; p = 0.01 vs baseline). Re-endothelialisation capacity was promoted by medium-size extracellular vesicles from controls, but not by medium-size extracellular vesicles from chronic coronary syndrome patients. High-intensity interval training for 4 weeks enhanced medium-size extracellular vesicle-mediated support of in vitro re-endothelialisation. Small extracellular vesicles from controls or chronic coronary syndrome patients increased endothelial cell death and reduced repair functions and were not affected by high-intensity interval training.

CONCLUSION

The present study demonstrates that medium-size extracellular vesicles and small extracellular vesicles differentially affect endothelial cell survival and repair responses. This equilibrium is unbalanced in patients with chronic coronary syndrome where leukocyte-derived medium-size extracellular vesicles are increased leading to a loss of medium-size extracellular vesicle-mediated endothelial repair. High-intensity interval training partially restored medium-size extracellular vesicle-mediated endothelial repair, underlining its use in cardiovascular prevention and therapy to improve endothelial function.

Effect of sinusoidal leg cycling exercise period on brachial artery blood flow dynamics in humans

Purpose

To quantify the dynamics of blood flow in brachial artery (BF-BA) in response to sinusoidal work rate (WR) leg cycling exercises of 2-, 4-, and 6-min periods and to examine their relationship with the forearm skin blood flow (SBF).

Methods

Seven healthy young male subjects performed upright leg ergometer exercise with a constant WR (mean sinusoidal WR) for 30 min followed by sinusoidal WR exercise of three different periods (number of repetitions): 2 min (7), 4 min (4), and 6 min (3). The WR fluctuated from 20 W to a peak WR corresponding to 60% peak oxygen uptake (VO₂). We continuously measured pulmonary gas exchange, heart rate (HR), blood velocity and cross-sectional area of BA, and forearm SBF and sweating rate (SR).

Results

All variables were followed by the sinusoidal WR. The phases of the variables for gas exchange and central circulation, such as VO₂ and HR with WR forcing were similar (e.g., phase shift (θ) in HR [°]: 2 min, 60 ± 7; 4 min, 45 ± 10; 6 min, 37 ± 8; mean ± SD) to previous study results, that is, a longer period showed a shorter θ and larger amplitude of responses. Contrarily, the BF-BA response showed anti-phase (approximately 180°) regardless of the period, whereas the θ of forearm SBF and SR were similar to gas exchange and central circulation.

Conclusions

Inactive limb BF-BA during sinusoidal leg cycling exercise was out of phase relative to the regulation of O₂-delivery to active muscles and thermoregulation. The response of BF-BA seems to not always reflect the response of forearm SBF in the downstream area.

Vascular improvements in individuals with type 2 diabetes following a 1 year randomised controlled exercise intervention, irrespective of changes in cardiorespiratory fitness

AIMS/HYPOTHESIS

Vascular changes in individuals with type 2 diabetes mellitus majorly contribute to the development of cardiovascular disease. Increased cardiorespiratory fitness (CRF) has been associated with improvements in vascular health. Although CRF tends to improve with exercise training, there remains a portion of participants with little or no improvement. Given the importance of vascular function in individuals with type 2 diabetes, we assessed whether individuals who failed to improve CRF following a 1 year exercise intervention also failed to improve arterial stiffness and structural indices.

METHODS

Individuals with type 2 diabetes with no major micro- and macrovascular complications and aged between 30 and 75 years old (n = 63) participated in a three-arm, 1 year, randomised controlled exercise intervention in Lisbon, Portugal. The study involved a non-exercise control group, a moderate continuous training combined with resistance training (RT) group and a high-intensity interval training with RT group. Allocation of participants into the intervention and control groups was done using a computer-generated list of random numbers. An improvement in CRF was defined as a change in [Formula: see text] ≥5%. Vascular stiffness and structural indices were measured using ultrasound imaging and applanation tonometry. Generalised estimating equations were used to compare changes in vascular measures across individuals in the control group (n = 22) and those in the exercise groups who either had improved CRF (CRF responders; n = 14) or whose CRF did not improve (CRF non-responders; n = 27) following 1 year of exercise training.

RESULTS

Compared with the control group, exercisers, with and without improvements in CRF, had decreased carotid intima-media thickness (IMT) (CRF responders: β = -2.84 [95% CI -5.63, -0.04]; CRF non-responders: β = -5.89 [95% CI -9.38, -2.40]) and lower-limb pulse wave velocity (PWV) (CRF responders: β = -0.14 [95% CI -0.25, -0.03]; CRF non-responders: β = -0.14 [95% CI -0.25, -0.03]), the latter being an indicator of peripheral arterial stiffness. Only CRF responders had decreased PWV of the upper limb compared with control participants (β = -0.12 [95% CI -0.23, -0.01]). As for central stiffness, CRF non-responders had increased aortic PWV compared with CRF responders (β = 0.19 [95% CI 0.07, 0.31]), whereas only the CRF non-responders had altered carotid distensibility coefficient compared with the control group (β = 0.00 [95% CI 3.01 × 10^-5, 0.00]). No interaction effects between the CRF responders and non-responders vs control group were found for the remaining stiffness or haemodynamic indices (p>0.05).

CONCLUSIONS/INTERPRETATION

Regardless of improvements in CRF, individuals with type 2 diabetes had significant improvements in carotid IMT and lower-limb arterial stiffness following a 1 year exercise intervention. Thus, a lack of improvement in CRF following exercise in people with type 2 diabetes does not necessarily entail a lack of improvement in vascular health.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03144505 FUNDING: This work was supported by fellowships from the Portuguese Foundation for Science and Technology. This work is also financed by a national grant through the Fundação para a Ciência e Tecnologia (FCT), within the unit I&D 472.

The hydromechanics in arteriogenesis

Coronary heart diseases are tightly associated with aging. Although current revascularization therapies, such as percutaneous coronary interventions (PCI) and coronary artery bypass graft (CABG), improve the clinical outcomes of patients with coronary diseases, their application and therapeutic effects are limited in elderly patients. Thus, developing novel therapeutic strategies, like prompting collateral development or the process of arteriogenesis, is necessary for the treatment of the elderly with coronary diseases. Arteriogenesis (ie, the vascular remodeling from pre‐existent arterioles to collateral conductance networks) functions as an essential compensation for tissue hypoperfusion caused by artery occlusion or stenosis, and its mechanisms remain to be elucidated. In this review, we will summarize the roles of the major hydromechanical components in laminar conditions in arteriogenesis, and discuss the potential effects of disturbed flow components in non‐laminar conditions.

Role of Blood Pressure in Mediating Carotid Artery Dilation in Response to Sympathetic Stimulation in Healthy, Middle-Aged Individuals

OBJECTIVES

Carotid artery diameter responses to sympathetic stimulation, i.e., carotid artery reactivity (CAR), represent a novel test of vascular health and relates to cardiovascular disease (CVD)/risk. This study aims to understand the relationship between the increase in blood pressure and carotid artery diameter response during the CAR-test in healthy, middle-aged men.

METHODS

Sample consisted of 40 normotensive men (aged 31-59 years) with no history of CVD of currently taking medication. Noninvasive ultrasound was used to measure carotid artery diameter during the cold pressor test (CPT), with CAR% being calculated as the relative change from baseline (%). Mean arterial pressure (MAP) was measured with beat-to-beat blood pressure recording.

RESULTS

CAR% was 4.4 ± 5.4%, peaking at 92 ± 43 seconds. MAP increased from 88 ± 9 mmHg to 110 ± 15 mmHg, peaked at 112 ± 38 seconds, which was significantly later than the diameter peak (P = 0.04). The correlation between resting MAP and CAR% was weak (r = 0.209 P = 0.197). Tertiles based on resting MAP or MAP-increase revealed no significant differences between groups in subject characteristics including age, body mass index, or CAR% (all P > 0.05). Subgroup analysis of individuals with carotid constriction (n = 6) vs. dilation (n = 34), revealed no significant difference in resting MAP or increase in MAP (P = 0.209 and 0.272, respectively).

CONCLUSION

Our data suggest that the characteristic increase in MAP during the CPT does not mediate carotid artery vasomotion.

Long-term exercise results in morphological and biomechanical changes in coronary resistance arterioles in male and female rats

Background

Biomechanical remodeling of coronary resistance arteries in physiological left ventricular hypertrophy has not yet been analyzed, and the possible sex differences are unknown.

Methods

Wistar rats were divided into four groups: male and female sedentary controls (MSe and FSe) and male and female animals undergoing a 12-week intensive swim training program (MEx and FEx). On the last day, the in vitro contractility, endothelium-dependent dilatation, and biomechanical properties of the intramural coronary resistance arteries were investigated by pressure microarteriography. Elastica and collagen remodeling were studied in histological sections.

Results

A similar outer radius and reduced inner radius resulted in an elevated wall to lumen ratio in the MEx and FEx animals compared to that in the sedentary controls. The wall elastic moduli increased in the MEx and FEx rats. Spontaneous and TxA₂ agonist-induced tone was increased in the FEx animals, whereas endothelium-dependent relaxation became more effective in MEx rats. Arteries of FEx rats had stronger contraction, while arteries of MEx animals had improved dilation.

Conclusions

According to our results, the coronary arterioles adapted to an elevated load during long-term exercise, and this adaptation depended on sex. It is important to emphasize that in addition to differences, we also found many similarities between the sexes in the adaptive response to exercise. The observed sport adaptation in the coronary resistance arteries of rats may contribute to a better understanding of the physiological and pathological function of these arteries in active and retired athletes of different sexes.

The Interplay between Vascular Function and Sexual Health in Prostate Cancer: The Potential Benefits of Exercise Training

Prostate cancer and its associated treatments can cause significant and lasting morbidities, such as cardiovascular and sexual dysfunctions. Various interventions have attempted to prevent or mitigate these dysfunctions. This review summarises the available evidence on the effects of exercise training on markers of cardiovascular disease (as assessed via vascular health outcomes) and sexual health in this prevalent cancer population. Current studies predominantly report blood pressure outcomes as a marker of vascular health, as well as various questionnaires assessing sexual health parameters, in men on active treatment (i.e., hormone or radiation therapies) or post-treatment. Preliminary evidence suggests that exercise interventions may elicit improvements in sexual function, but not blood pressure, in these populations. Future studies in more advanced and varied prostate cancer populations (i.e., those on chemotherapies or immunotherapies, or undergoing active surveillance) are required to ascertain the duration, intensity and frequency of exercise that optimises the effects of exercise training on cardiovascular and sexual dysfunctions (and their relationship) in men during and following treatment for prostate cancer.

Exercise-Induced Vascular Adaptations under Artificially Versus Pathologically Reduced Blood Flow: A Focus Review with Special Emphasis on Arteriogenesis

Background: The vascular effects of training under blood flow restriction (BFR) in healthy persons can serve as a model for the exercise mechanism in lower extremity arterial disease (LEAD) patients. Both mechanisms are, inter alia, characterized by lower blood flow in the lower limbs. We aimed to describe and compare the underlying mechanism of exercise-induced effects of disease- and external application-BFR methods. Methods: We completed a narrative focus review after systematic literature research. We included only studies on healthy participants or those with LEAD. Both male and female adults were considered eligible. The target intervention was exercise with a reduced blood flow due to disease or external application. Results: We identified 416 publications. After the application of inclusion and exclusion criteria, 39 manuscripts were included in the vascular adaption part. Major mechanisms involving exercise-mediated benefits in treating LEAD included: inflammatory processes suppression, proinflammatory immune cells, improvement of endothelial function, remodeling of skeletal muscle, and additional vascularization (arteriogenesis). Mechanisms resulting from external BFR application included: increased release of anabolic growth factors, stimulated muscle protein synthesis, higher concentrations of heat shock proteins and nitric oxide synthase, lower levels in myostatin, and stimulation of S6K1. Conclusions: A main difference between the two comparators is the venous blood return, which is restricted in BFR but not in LEAD. Major similarities include the overall ischemic situation, the changes in microRNA (miRNA) expression, and the increased production of NOS with their associated arteriogenesis after training with BFR.

Mimicking exercise: what matters most and where to next?

The past decade has witnessed growing scientific and commercial interest in the identification of bioactive oral compounds that mimic or potentiate the effects of exercise, so-called 'exercise pills' or 'exercise mimetics.' These compounds have, to date, typically targeted skeletal muscle in an attempt to stimulate some of the adaptations to exercise induced by endurance training. Accordingly, they fail to impart many of the broad health protecting effects of exercise that are seen in tissues and organs other than skeletal muscle. In the context that multiple integrative regulatory and often redundant pathways have evolved to detect and respond to human movement, here we consider the complex challenges of designing a pill that might mimic the extensive range of exercise benefits. In particular, we consider the limits of the current 'myocentric' paradigm given the wide-ranging array of impacts that exercise exerts on atherosclerosis and the cardiovascular system. We discuss the validity and limitations of the concept that low dose cardiovascular polypills, already in large scale trials, may represent one form of cardiovascular exercise mimetic. Finally, given that some calls for an exercise pill stem from a response to the perceived failure of expert advice, evidence-based guidelines and current public health approaches, we explore possible strategies that might address the global rise in inactivity. In the event that a broad spectrum exercise mimetic might ever be developed, we discuss some generic issues related to adoption and adherence of therapeutic interventions.

Exercise and Peripheral Arteriosclerosis

Adaptation of a healthy lifestyle including adequate daily physical activity is shown to reduce 80% of cardiovascular mortality and 40% of cancer-related deaths. A large body of evidence exists proving that this relationship is dose dependent, and even half of the recommended normal physical activity yields significant risk reduction. There has been no medical therapy that would provide such high percentages of reduction in mortality to date. The World Health Organization, therefore, has started an initiative to implement exercise into daily life as a primary prevention measure. Herein, we will focus on the effects of exercise on the vasculature, mainly the peripheral vasculature, in the context of atherosclerotic disease. Exercise has a fundamental role in the pathogenesis, diagnosis, and treatment of atherosclerotic vascular disease. It exerts a protective effect against the development of atherosclerosis irrespective of other cardiovascular risk factors. Additionally, exercise induces changes in vascular hemodynamics helping us to elucidate the presence of obscure vascular involvement. Once again, exercise is the main treatment modality in peripheral arterial disease with accumulating evidence to reduce symptoms and improve both exercise capacity and cardiovascular symptoms.

Assessment of resistance vessel function in human skeletal muscle: guidelines for experimental design, Doppler ultrasound, and pharmacology

The introduction of duplex Doppler ultrasound almost half a century ago signified a revolutionary advance in the ability to assess limb blood flow in humans. It is now widely used to assess blood flow under a variety of experimental conditions to study skeletal muscle resistance vessel function. Despite its pervasive adoption, there is substantial variability between studies in relation to experimental protocols, procedures for data analysis, and interpretation of findings. This guideline results from a collegial discussion among physiologists and pharmacologists, with the goal of providing general as well as specific recommendations regarding the conduct of human studies involving Doppler ultrasound-based measures of resistance vessel function in skeletal muscle. Indeed, the focus is on methods used to assess resistance vessel function and not upstream conduit artery function (i.e., macrovasculature), which has been expertly reviewed elsewhere. In particular, we address topics related to experimental design, data collection, and signal processing as well as review common procedures used to assess resistance vessel function, including postocclusive reactive hyperemia, passive limb movement, acute single limb exercise, and pharmacological interventions.

Impact of Short-Term Continuous and Interval Exercise Training on Endothelial Function and Glucose Metabolism in Prediabetes

INTRODUCTION

The impact of interval (INT) vs. continuous (CONT) exercise training on endothelial function in relation to glucose metabolism prior to clinically meaningful weight loss is unknown in adults with prediabetes.

METHODS

Twenty-six subjects with prediabetes (60 ± 1 y; 33 ± 1 kg/m2; 2-hr-PG OGTT: 145 ± 7 mg/dl) were randomized to 60 min of CONT (n = 12; 70% of HRpeak) or work-matched INT exercise training (n = 14; alternating 3 min at 90 and 50% HRpeak) for 2 weeks. Aerobic fitness (VO2peak) and body composition (bioelectrical impedance) were assessed before and after training. Flow-mediated dilation (FMD) was measured during a 2 h 75 g OGTT (0, 60, and 120 min) to assess endothelial function. Postprandial FMD was calculated as incremental area under the curve (iAUC). Glucose tolerance and insulin were also calculated by iAUC. Fasting plasma VCAM, ICAM, and hs-CRP were also assessed as indicators of vascular/systemic inflammation.

RESULTS

Both interventions increased VO2peak (P = 0.002) but had no effect on body fat (P = 0.20). Although both treatments improved glucose tolerance (P = 0.06) and insulin iAUC (P = 0.02), VCAM increased (P = 0.01). There was no effect of either treatment on ICAM, hs-CRP, or fasting as well as postprandial FMD. However, 57% of people improved fasting and iAUC FMD following CONT compared with only 42% after INT exercise (each: P = 0.04). Elevated VCAM was linked to blunted fasting FMD after training (r = -0.38, P = 0.05). But, there was no correlation between fasting FMD or postprandial FMD with glucose tolerance (r = 0.17, P = 0.39 and r = 0.02, P = 0.90, respectively) or insulin iAUC following training (r = 0.34, P = 0.08 and r = 0.04, P = 0.83, respectively).

CONCLUSION

Endothelial function is not improved consistently after short-term training, despite improvements in glucose and insulin responses to the OGTT in obese adults with prediabetes.

In-exercise vascular shear rate during acute continuous and interval exercise: impact on endothelial function and miR-21

Endothelial cell phenotype and endothelial function are regulated by hemodynamic forces, particularly wall shear stress (WSS). During a single bout of exercise, the specific exercise protocol can affect in-exercise WSS patterns and, consequently, endothelial function. MicroRNAs might provide a biomarker of in-exercise WSS pattern to indicate whether a specific exercise bout will have a positive effect on endothelial function. We evaluated the effect of acute interval (IT) and continuous (CON) in-exercise WSS patterns upon postexercise endothelial function and circulating microRNA (miR)-21 expression. Methods and results: 13 participants performed CON and 3 different IT exercise protocols matched for duration and intensity on separate days. Oxygen uptake, heart rate, and brachial artery blood flow were recorded throughout the exercise. Brachial artery flow-mediated dilation (FMD) was performed pre-exercise and 15 min postexercise. Plasma samples were acquired pre-exercise and 6 h postexercise to determine miR-21 expression. In-exercise shear rate (SR) patterns (a surrogate of WSS) differed according to the CON or IT work-rate profile. In-exercise anterograde SR was greater in CON than IT exercise ( P < 0.05), but retrograde SR was equivalent between exercise protocols ( P > 0.05). Oscillatory shear index was higher during IT versus CON exercise ( P < 0.05). Postexercise FMD increased (pre: 7.08% ± 2.95%, post: 10.54% ± 4.24%, P < 0.05), whereas miR-21 expression was unchanged (pre: 12.0% ± 20.7% cel-miR-39, post: 11.1 ± 19.3% cel-miR-39, P > 0.05) with no effect of exercise protocol ( P > 0.05). Conclusions: CON and IT exercise induced different SR patterns but equivalent improvements in acute endothelial function. The absence of change in miR-21 expression suggests that miR-21 is not a suitable biomarker of exercise-induced SR.

NEW & NOTEWORTHY Interval exercise has the potential to negatively impact vascular adaptations because of repeated oscillations in vascular shear. To our knowledge, we are the first to continuously assess exercise-induced shear throughout different acute exercise protocols and examine its relationship with acute endothelial function and a circulating biomarker of shear (miR-21). These experiments provide clear data indicating enhancement of the acute vascular response from differing interval exercise protocols, with the study also providing detailed vascular and shear responses for future reference.

Impact of Vascular Function on Maximum Power Output in Elite Handball Athletes

Purpose: To evaluate vascular function and its relationship to cardiorespiratory fitness in professional handball athletes. Method: We examined 30 male professional handball athletes (age 27 ± 4 y) and 10 male sedentary controls (age 26 ± 5 y) at rest. The workup included exercise testing via ergometry. To assess vascular function, a validated electronic model of the arterial tree (vasc assist 2®) was used. It replicates noninvasively acquired pulse pressure waves by modulating the relevant functional parameters of compliance, resistance, inertia, pressure, and flow. The maximum oxygen uptake (VO2max) was estimated using the validated heart rate ratio method. Results: Athletes had a significantly lower systolic and diastolic central blood pressure (cBP) compared to controls (102 ± 9/60 ± 9 vs. 110 ± 8/74 ± 9 mmHg, p < .01), whereas aortic pulse wave velocity (PWV) (6.2 ± 0.8 vs. 6.3 ± 0.5 m/s, p = .45) and augmentation index at a heart rate of 75 (Aix@75) (-4 ± 12 vs. -13 ± 16%, p = .06) were not different. Resistance index (R) (15.9 ± 4.4 vs. 10.6 ± 0.6, p = .001) and maximum power output (MPO) (3.55 ± 0.54 vs. 2.46 ± 0.55 Watt/kg, p < .001) were significantly higher in athletes compared to controls. We found no relevant correlation between MPO, resting heart rate, PWV, Aix@75, and cBP. A higher VO2max (p = .02) and a lower R (p < .01) were significant predictors of a higher MPO in athletes. Conclusion: R had an independent and strong correlation to MPO in athletes, which might help to disentangle the contribution of aerobic capacity and arterial function to physical power.

The impact of hypoxaemia on vascular function in lowlanders and high altitude indigenous populations

Exposure to hypoxia elicits widespread physiological responses that are critical for successful acclimatization; however, these responses may induce apparent maladaptive consequences. For example, recent studies conducted in both the laboratory and the field (e.g. at high altitude) have demonstrated that endothelial function is reduced in hypoxia. Herein, we review the several proposed mechanism(s) pertaining to the observed reduction in endothelial function in hypoxia including: (i) changes in blood flow patterns (i.e. shear stress), (ii) increased inflammation and production of reactive oxygen species (i.e. oxidative stress), (iii) heightened sympathetic nerve activity, and (iv) increased red blood cell concentration and mass leading to elevated nitric oxide scavenging. Although some of these mechanism(s) have been examined in lowlanders, less in known about endothelial function in indigenous populations that have chronically adapted to environmental hypoxia for millennia (e.g. the Peruvian, Tibetan and Ethiopian highlanders). There is some evidence indicating that healthy Tibetan and Peruvian (i.e. Andean) highlanders have preserved endothelial function at high altitude, but less is known about the Ethiopian highlanders. However, Andean highlanders suffering from chronic mountain sickness, which is characterized by an excessive production of red blood cells, have markedly reduced endothelial function. This review will provide a framework and mechanistic model for vascular endothelial adaptation to hypoxia in lowlanders and highlanders. Elucidating the pathways responsible for vascular adaption/maladaptation to hypoxia has potential clinical implications for disease featuring low oxygen delivery (e.g. heart failure, pulmonary disease). In addition, a greater understanding of vascular function at high altitude will clinically benefit the global estimated 85 million high altitude residents.

Cerebral blood flow responses to exercise are enhanced in left ventricular assist device patients after an exercise rehabilitation program

Cerebral blood flow during exercise is impaired in patients with heart failure implanted with left ventricular assist devices (LVADs). Our aim was to determine whether a 3-mo exercise training program could mitigate cerebrovascular dysfunction. Internal carotid artery (ICA) blood flow and intracranial middle (MCAv) and posterior cerebral (PCAv) artery velocities were measured continuously using Doppler ultrasound, alongside cardiorespiratory measures at rest and in response to an incremental cycle ergometer exercise protocol in 12 LVAD participants (5 female, 53.6 ± 11.8 yr; 84.2 ± 15.7 kg; 1.73 ± 0.08) pre- (PreTR) and post- (PostTR) completion of a 3-mo supervised exercise rehabilitation program. At rest, only PCAv was different PostTR (38.1 ± 10.4 cm/s) compared with PreTR (43.0 ± 10.8 cm/s; P < 0.05). PreTR, the reduction in PCAv observed from rest to exercise (5.2 ± 1.8%) was mitigated PostTR (P < 0.001). Similarly, exercise training enhanced ICA flow during submaximal exercise (~8.6 ± 13.7%), resulting in increased ICA flow PostTR compared with a reduced flow PreTR (P < 0.001). Although both end-tidal partial pressure of carbon dioxide and mean arterial pressure responses during incremental exercise were greater PostTR than PreTR, only the improved PETCO2 was related to the improved ICA flow (R² = 0.14; P < 0.05). Our findings suggest that short-term exercise training improves cerebrovascular function during exercise in patients with LVADs. This finding should encourage future studies investigating long-term exercise training and cerebral and peripheral vascular adaptation.NEW & NOTEWORTHY Left ventricular assist devices, now used as destination therapy in end-stage heart failure, enable patients to undertake rehabilitative exercise training. We show, for the first time in humans, that training improves cerebrovascular function during exercise in patients with left ventricular assist devices. This finding may have implications for cerebrovascular health in patients with heart failure.

Acute Effect of High-Intensity Interval Cycling on Carotid Arterial Stiffness and Hemodynamics

Background

Cardiovascular disease (CVD) contributes to be one of the leading causes of death in the population worldwide. Carotid arterial stiffness and local hemodynamics are associated with the occurrence and development of CVD. Therefore, understanding the alterations of human carotid arterial stiffness and hemodynamics is of great clinical value in the prevention and treatment of CVD.

Objective

In this study, we aimed to investigate the acute effect of high-intensity interval cycling (HIIC) on carotid arterial stiffness and hemodynamics in sedentary.

Methods

Thirty volunteered healthy sedentary males were enrolled in this study. HIIC intervention (3 sets, 20 s per set) was performed individually. A color Doppler ultrasound was applied to detect the images of the arterial inner diameters and center-line velocity waveforms at the right common carotid artery at different time points (at rest, 3 min, 15 min, and 30 min) after HIIC. Synchronously, electronic manometer was used to measure the systolic and diastolic pressures at the left brachial artery.

Results

Arterial stiffness increased and arterial diameter decreased significantly after acute HIIC. The variation in stiffness persisted for 30 min, at least 15 min longer than the change in diameter. At 3 min after exercise, maximum and mean wall shear stresses (WSS) increased and minimum WSS was also higher than the resting value. At 30 min after exercise, WSS returned to the baseline, but oscillating shear index was still higher than the resting value.

Conclusions

In summary, arterial stiffness and hemodynamics changed significantly not only at 3 min but also at 30 min after acute HIIC.

Requirement of β1 integrin for endothelium-dependent vasodilation and collateral formation in hindlimb ischemia

An acute increase in blood flow triggers flow-mediated dilation (FMD), which is mainly mediated by endothelial nitric oxide synthase (eNOS). A long-term increase in blood flow chronically enlarges the arterial lumen, a process called arteriogenesis. In several common human diseases, these processes are disrupted for as yet unknown reasons. Here, we asked whether β1 integrin, a mechanosensory protein in endothelial cells, is required for FMD and arteriogenesis in the ischemic hindlimb. Permanent ligation of the femoral artery in C57BL/6 J mice enlarged pre-existing collateral arteries and increased numbers of arterioles in the thigh. In the lower leg, the numbers of capillaries increased. Notably, injection of β1 integrin-blocking antibody or tamoxifen-induced endothelial cell-specific deletion of the gene for β1 integrin (Itgb1) inhibited both arteriogenesis and angiogenesis. Using high frequency ultrasound, we demonstrated that β1 integrin-blocking antibody or endothelial cell-specific depletion of β1 integrin attenuated FMD of the femoral artery, and blocking of β1 integrin function did not further decrease FMD in eNOS-deficient mice. Our data suggest that endothelial β1 integrin is required for both acute and chronic widening of the arterial lumen in response to hindlimb ischemia, potentially via functional interaction with eNOS.

Impact of high sodium intake on blood pressure and functional sympatholysis during rhythmic handgrip exercise

High dietary sodium intake is a risk factor for arterial hypertension; given that the ability to overcome sympathetically mediated vasoconstriction (functional sympatholysis) is attenuated in individuals with hypertension, we investigated the cardiovascular responses to high salt (HS) intake in healthy humans. We hypothesized that a HS intake of 15 g/day for 7 days would attenuate functional sympatholysis and augment the blood pressure response to handgrip exercise (HGE). Thirteen participants (6 males, 7 females) underwent 2 individual days of testing. Beat-by-beat blood pressure and heart rate were recorded throughout the trial on the non-exercising limb. Forearm blood flow was derived from ultrasonography on the brachial artery of the exercising limb. Participants then underwent a flow-mediated dilation (FMD) test. Next, a submaximal HGE was performed for 7 min with lower body negative pressure initiated during minutes 5-7. A single spot urine sample revealed a significant increase in sodium excretion during the HS conditions (p < 0.01). FMD was reduced during the HS condition. Mean arterial pressure was significantly higher during HS intake. No alteration to functional sympatholysis was found between conditions (p > 0.05). In summary, HS intake increases blood pressure without impacting functional sympatholysis or blood pressure responsiveness during HGE. These findings indicate that brachial artery dysfunction precedes an inefficient functional sympatholysis. Novelty Functional sympatholysis was not impacted by 1 week of high sodium intake. High sodium intake augmented the rate pressure product during handgrip exercise in healthy humans.

Effect of Morning Exercise With or Without Breaks in Prolonged Sitting on Blood Pressure in Older Overweight/Obese Adults

Both exercise and breaks in prolonged sitting can reduce blood pressure (BP) in older overweight/obese adults. We investigated whether there is an additive hypotensive effect when exercise is combined with subsequent breaks in sitting. Sex differences and changes in plasma catecholamines as a potential candidate mechanism underlying BP responses were also examined. Sedentary older adults (n=67; 67±7 years; 31.2±4.1 kg/m²) completed 3 conditions in random order-sitting (SIT): uninterrupted sitting (8 hours, control); exercise+sitting (EX+SIT): sitting (1 hour), moderate-intensity walking (30 minutes), uninterrupted sitting (6.5 hours); exercise+breaks (EX+BR): sitting (1 hour), moderate-intensity walking (30 minutes), sitting interrupted every 30 minutes with 3 minutes of light-intensity walking (6.5 hours). Serial BP and plasma epinephrine/norepinephrine measurements occurred during 8 hours. The 8-hour average systolic and diastolic BP (mm Hg 95% CI) was lower in EX+SIT -3.4 (-4.5 to -2.3), -0.8 (-1.6 to -0.04), and EX+BR -5.1 (-6.2 to -4.0), -1.1 (-1.8 to -0.3), respectively, relative to SIT (all P <0.05). There was an additional reduction in average systolic BP of -1.7 (-2.8 to -0.6) in EX+BR relative to EX+SIT ( P=0.003). This additional reduction in systolic BP was driven by women -3.2 (-4.7 to -1.7; P<0.001 EX+BR versus EX+SIT). Average epinephrine decreased in EX+SIT and EX+BR in women (-13% to -12%) but increased in men (+12% to +23%), respectively, relative to SIT ( P<0.05). No differences in average norepinephrine were observed. Morning exercise reduces BP during a period of 8 hours in older overweight/obese adults compared with prolonged sitting. Combining exercise with regular breaks in sitting may be of more benefit for lowering BP in women than in men. Clinical Trial Registration- URL: https://www.anzctr.org.au . Unique identifier: ACTRN12614000737639.

Physical Exercise and Selective Autophagy: Benefit and Risk on Cardiovascular Health

Physical exercise promotes cardiorespiratory fitness, and is considered the mainstream of non-pharmacological therapies along with lifestyle modification for various chronic diseases, in particular cardiovascular diseases. Physical exercise may positively affect various cardiovascular risk factors including body weight, blood pressure, insulin sensitivity, lipid and glucose metabolism, heart function, endothelial function, and body fat composition. With the ever-rising prevalence of obesity and other types of metabolic diseases, as well as sedentary lifestyle, regular exercise of moderate intensity has been indicated to benefit cardiovascular health and reduce overall disease mortality. Exercise offers a wide cadre of favorable responses in the cardiovascular system such as improved dynamics of the cardiovascular system, reduced prevalence of coronary heart diseases and cardiomyopathies, enhanced cardiac reserve capacity, and autonomic regulation. Ample clinical and experimental evidence has indicated an emerging role for autophagy, a conservative catabolism process to degrade and recycle cellular organelles and nutrients, in exercise training-offered cardiovascular benefits. Regular physical exercise as a unique form of physiological stress is capable of triggering adaptation while autophagy in particular selective autophagy seems to be permissive to such cardiovascular adaptation. Here in this mini-review, we will summarize the role for autophagy in particular mitochondrial selective autophagy namely mitophagy in the benefit versus risk of physical exercise on cardiovascular function.

Sixteen-Week Physical Activity Intervention in Subjects With Increased Cardiometabolic Risk Shifts Innate Immune Function Towards a Less Proinflammatory State

Background

Low‐grade inflammation, largely mediated by monocyte‐derived macrophages, contributes to atherosclerosis. Sedentary behavior is associated with atherosclerosis and cardiovascular diseases (CVD). We examined whether reducing sedentary behavior and improving walking time improves monocyte inflammatory phenotype in subjects with increased cardiovascular risk.

Methods and Results

Across 2 waves, 16 individuals with increased cardiovascular risk performed a 16‐week intervention study (age 64±6 years, body mass index 29.9±4.3 kg/m²), using a device with vibration feedback to promote physical activity. Before and after intervention, we objectively examined physical activity (ActivPAL), cytokine production capacity after ex vivo stimulation in peripheral blood mononuclear cells, metabolism of peripheral blood mononuclear cells, circulating cytokine concentrations, and monocyte immunophenotype. Overall, no significant increase in walking time was found (1.9±0.7 to 2.2±1.2 h/day, P=0.07). However, strong, inverse correlations were observed between the change in walking time and the change in production of interleukin (IL)‐1β, IL‐6, IL‐8, and IL‐10 after lipopolysaccharide stimulation (r_s=−0.655, −0.844, −0.672, and −0.781, respectively, all P<0.05). After intervention optimization based on feedback from wave 1, participants in wave 2 (n=8) showed an increase in walking time (2.2±0.8 to 3.0±1.3 h/day, P=0.001) and attenuated cytokine production of IL‐6, IL‐8, and IL‐10 (all P<0.05). Glycolysis (P=0.08) and maximal OXPHOS (P=0.04) of peripheral blood mononuclear cells decreased after intervention. Lower IL‐6 concentrations (P=0.06) and monocyte percentages (P<0.05), but no changes in monocyte subsets were found.

Conclusions

Successfully improving walking time shifts innate immune function towards a less proinflammatory state, characterized by a lower capacity to produce inflammatory cytokines, in individuals with increased cardiovascular risk.

Clinical Trial Registration Information

URL: http://www.trialregister.nl. Unique identifier: NTR6387.

Aerobic Interval Training Impacts Muscle and Brain Oxygenation Responses to Incremental Exercise

The purpose of the present study was to assess the effects of aerobic interval training on muscle and brain oxygenation to incremental ramp exercise. Eleven physically active subjects performed a 6-week interval training period, proceeded and followed by an incremental ramp exercise to exhaustion (25 W min^–1). Throughout the tests pulmonary gas exchange and muscle (Vastus Lateralis) and brain (prefrontal cortex) oxygenation [concentration of deoxygenated and oxygenated hemoglobin, HHb and O₂Hb, and tissue oxygenation index (TOI)] were continuously recorded. Following the training intervention V.⁢O2_peak had increased with 7.8 ± 5.0% (P < 0.001). The slope of the decrease in muscle TOI had decreased (P = 0.017) 16.6 ± 6.4% and the amplitude of muscle HHb and totHb had increased (P < 0.001) 40.4 ± 15.8 and 125.3 ± 43.1%, respectively. The amplitude of brain O₂Hb and totHb had increased (P < 0.05) 40.1 ± 18.7 and 26.8 ± 13.6%, respectively. The training intervention shifted breakpoints in muscle HHb, totHb and TOI, and brain O₂Hb, HHb, totHb and TOI to a higher absolute work rate and V.⁢O2 (P < 0.05). The relative (in %) change in V.⁢O2_peak was significantly correlated to relative (in %) change slope of muscle TOI (r = 0.69, P = 0.011) and amplitude of muscle HHb (r = 0.72, P = 0.003) and totHb (r = 0.52, P = 0.021), but not to changes in brain oxygenation. These results indicate that interval training affects both muscle and brain oxygenation, coinciding with an increase in aerobic fitness (i.e., V.⁢O2_peak). The relation between the change in V.⁢O2_peak and muscle but not brain oxygenation suggests that brain oxygenation per se is not a primary factor limiting exercise tolerance during incremental exercise.

Reversible Thermoresponsive Hydrogel Fabricated from Natural Biopolymer for the Improvement of Critical Limb Ischemia by Controlling Release of Stem Cells

Stem cells therapy is an effective treatment for critical limb ischemia diseases (CLI), but is limited to low cells retention and poor target release in severe ischemia tissues. Due to the notable feature of CLI, namely, the temperature of ischemia tissues decreases with the severity of the lesions, a thermoresponsive and reversible hydrogel based on methylcellulose-salt system encapsulating stem cells is facilely prepared and successfully achieved the goal of releasing stem cells in lower temperature areas. The investigations show that the thermogel presents notable biocompatibility, thermoresponsiveness, and cytoprotection. Furthermore, the combined transplantation of hydrogel and stem cells system effectively inhibits the fibrosis and muscular atrophy of lower limb ischemia, accelerates the recovery of lower limb blood flow, and promotes angiogenesis, indicating that the reversible thermogel can promote vascular repair by controlling the release of loaded stem cells in the treatment of CLI.

Selection of endurance capabilities and the trade-off between pressure and volume in the evolution of the human heart

Chimpanzees and gorillas, when not inactive, engage primarily in short bursts of resistance physical activity (RPA), such as climbing and fighting, that creates pressure stress on the cardiovascular system. In contrast, to initially hunt and gather and later to farm, it is thought that preindustrial human survival was dependent on lifelong moderate-intensity endurance physical activity (EPA), which creates a cardiovascular volume stress. Although derived musculoskeletal and thermoregulatory adaptations for EPA in humans have been documented, it is unknown if selection acted similarly on the heart. To test this hypothesis, we compared left ventricular (LV) structure and function across semiwild sanctuary chimpanzees, gorillas, and a sample of humans exposed to markedly different physical activity patterns. We show the human LV possesses derived features that help augment cardiac output (CO) thereby enabling EPA. However, the human LV also demonstrates phenotypic plasticity and, hence, variability, across a wide range of habitual physical activity. We show that the human LV's propensity to remodel differentially in response to chronic pressure or volume stimuli associated with intense RPA and EPA as well as physical inactivity represents an evolutionary trade-off with potential implications for contemporary cardiovascular health. Specifically, the human LV trades off pressure adaptations for volume capabilities and converges on a chimpanzee-like phenotype in response to physical inactivity or sustained pressure loading. Consequently, the derived LV and lifelong low blood pressure (BP) appear to be partly sustained by regular moderate-intensity EPA whose decline in postindustrial societies likely contributes to the modern epidemic of hypertensive heart disease.

Individual Adaptation in Cross-Country Skiing Based on Tracking during Training Conditions

Research on heart rate (HR), mean arterial pressure (MAP) and blood pressure (BP) during specific training stages is less common in endurance athletes, whereas resting BP and HR are less studied in relationship to HR_max. In the current study, the objective was to conduct a medium-term HR, BP and MAP analysis while tracking individual training outcomes. The study was conducted during the 2017–2018 season, over 43 days and 1033 km of training volume, on 12 competitive male cross-country ski athletes. One VO_2max test was performed 10 days before the start of the training program. After the test, training volume and intensity was preset for each subject, according to the general training methodology. Early morning HR, MAP and BP measurements were taken as part of the basic functional analysis. Training volume was correlated to both distance (p = 0.01, r = 0.85, CI95% = 0.80 to 0.88) and training HR%, namely the percentage of HR_max (p = 0.01, r = −0.47, CI95% = −0.58 to −0.34). Both the supine (sHR) and orthostatic HR (oHR) values were significantly correlated with the training intensity. We obtained a significant correlation between sHR and oHR values and the training objective (p = 0.01). An increased oHR was correlated to high intensity training activity (HIT) during the second training session (p = 0.01). Heart rate and blood pressure measurements represent predictive functional adaptation parameters over different training phases. We highlight a link between sHR, oHR, MAP data, and the athletes’ ability to perform in lower effort zones during physical exertion. However, we failed to validate MAP as a cardiovascular stress indicator following high intensity training.

The effects of moderate and high-intensity exercise on circulating markers of endothelial integrity and activation in young, healthy men

Endothelial function typically exhibits a hormetic response to exercise. It is unknown whether endothelial damage occurs in response to acute exercise and could be a contributing mechanism. We sought to determine the effects of acute exercise on endothelial-derived circulating factors proposed to reflect endothelial integrity and activation. Young, healthy men (n = 10) underwent 30-min moderate continuous (MOD) and high-intensity interval (HII) cycling exercise bouts. Venous blood samples were taken immediately before and after exercise for quantification of circulating endothelial cells (CECs), circulating angiogenic cells (CACs), apoptotic and activated endothelial microvesicles (EMVs), thrombomodulin (TM), von Willebrand factor (vWF), syndecan-1, and circulating microRNAs (ci-miRs) 126-3p and 126-5p. Endothelial function was assessed by flow-mediated dilation (FMD) of the brachial artery before, 10 min after, and 60 min after exercise. Numbers of CECs and EMVs were unchanged by either exercise bout (P > 0.05). Numbers of all measured CAC subtypes decreased in response to MOD (21%-34%, P < 0.05), whereas only CD31⁺/34⁺/45^dim/- CACs decreased following HII (21%, P < 0.05). TM and syndecan-1 increased with both exercise intensities (both ~20%, P < 0.05). HII, but not MOD, increased vWF (88%, P < 0.001), ci-miR-126-3p (92%, P = 0.009) and ci-miR-126-5p (110%, P = 0.01). The changes in several circulating factors correlated with changes in FMD following either one or both intensities. Changes in circulating factors do not support the concept of exercise-induced endothelial cell denudation, apoptosis, or activation, though slight disruption of endothelial glycocalyx and membrane integrity may occur. A related loss of mechanotransduction along with mechanisms underlying endothelial activation and ci-miR-126 secretion may relate to changes in endothelial function.NEW & NOTEWORTHY Using circulating endothelial-derived factors, we show that endothelial denudation, apoptosis, and activation do not appear to increase, whereas disrupted endothelial glycocalyx and membrane integrity may occur during both high-intensity interval and moderate intensity cycling. Increases in factors nonspecific to endothelial damage, including von Willebrand factor and microRNA-126, occurred only after high-intensity interval exercise. These results shed light on the hypothesis that disrupted endothelial integrity contributes to the endothelial function response to exercise.