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The objective of this review is to identify the acute effects of blood flow restriction (BFR) with vs without exercise on endothelial function in healthy individuals and the changes in endothelial function in young and older adults following different levels of exclusive BFR vs free flow. Systematic searches were performed in the following databases: PubMed, Web of Science, Scopus, and Cochrane Library, from inception to July 17, 2021. The studies included healthy individuals who underwent assessments of endothelial function before and after experimental protocols through endothelium-dependent flow-mediated dilatation. In total, 4890 studies were screened, and 6 studies of moderate-to-high methodological quality (Physiotherapy Evidence Database scores 6 - 10) including 82 subjects (aged 24 - 68 years) were eligible. Overall, flow-mediated dilatation increased in the non-cuffed arm immediately and 15 minutes after exercise, with no change in the cuffed arm (BFR of 60 - 80 mmHg). In protocols without exercise, cuff pressures of 25 - 30 mmHg applied for 30 minutes did not promote changes in the endothelial function, while those > 50 mmHg induced a dose-dependent attenuation of flow-mediated dilatation only in young individuals. A moderate level of BFR appears to have no effect on endothelial function after acute exercise. In non-exercise conditions, reductions in flow-mediated dilatation seem to result from increased retrograde shear provoked by cuff pressures ≥ 50 mmHg in young but not in older adults. An exercise-related increase in antegrade shear rate leads to a greater nitric oxide-mediated vasodilator response. However, BFR appears to attenuate this effect in young but not in older individuals.

Abstract Background Evidence of the benefits induced from resistance exercise on health markers of post-bariatric patients is limited. The study will investigate the effects of a resistance training (RT) program on muscle mass and strength, bone metabolism biomarkers, bone mineral density (BMD), bone microarchitecture, and endothelial function of patients subjected to Roux-en-Y gastric bypass. Methods/design This randomized controlled trial will include 60 post-bariatric patients, physically inactive, aging 18 to 50 years, with a post-surgery period ≥ 12 months. They will be randomly assigned into two groups: (i) the non-exercised control group, which will receive the standard clinical follow-up, or (ii) the intervention group which will consist of RT (60 min/session; 3 times/week, for 6 months). The primary outcomes will include muscle mass and strength, bone metabolism biomarkers, BMD, and bone microarchitecture. The secondary outcomes will be anthropometry, hemodynamic measurements, cardiovascular risk factors, health-related quality of life (QoL), and endothelial function. Outcomes will be assessed by blood biomarkers of bone formation and reabsorption, dual X-ray absorptiometry, repetition maximum and handgrip strength tests, high-resolution peripheral quantitative computed tomography, 36-Item Short-Form Health Survey, venous occlusion plethysmography, and nailfold videocapillaroscopy. Discussion It is expected that there are greater benefits from the RT program, possibly improving muscle mass and strength, bone metabolism, density and microarchitecture, QoL, and cardiovascular risk. Trial registration ClinicalTrials.gov NCT04193397. Registered on 7 December 2019.

ABSTRACT Objective: We investigated the biological behavior of ghrelin and glucagon-like peptide-1 (GLP-1) after a standard liquid meal according to body adiposity and glucose homeostasis. Subjects and methods: This cross-sectional study included 41 individuals (92.7% women; aged 38.3 ± 7.8 years; BMI 32.2 ± 5.5 kg/m²) allocated into three groups according to body adiposity and glucose homeostasis, as follows: normoglycemic eutrophic controls (CON, n = 11), normoglycemic with obesity (NOB, n = 15), and dysglycemic with obesity (DOB, n = 15). They were tested at fasting and 30 and 60 min after the ingestion of a standard liquid meal in which we measured active ghrelin, active GLP-1, insulin, and plasma glucose levels. Results: As expected, DOB exhibited the worst metabolic status (glucose, insulin, HOMA-IR, HbA1c) and an inflammatory status (TNF-α) at fasting, besides a more significant increase in glucose than postprandial NOB (p ≤ 0.05). At fasting, no differences between groups were detected in lipid profile, ghrelin, and GLP-1 (p ≥ 0.06). After the standard meal, all groups exhibited a reduction in ghrelin levels between fasting vs. 60 min (p ≤ 0.02). Additionally, we noticed that GLP-1 and insulin increased equally in all groups after the standard meal (fasting vs. 30 and 60 min). Although glucose levels increased in all groups after meal intake, these changes were significantly more significant in DOB vs. CON and NOB at 30 and 60 min post-meal (p ≤ 0.05). Conclusions: Time course of ghrelin and GLP-1 levels during the postprandial period was not influenced by body adiposity or glucose homeostasis. Similar behaviors occurred in controls and patients with obesity, independently of glucose homeostasis.

Background: Evidence on the effects of exercise training on the bone health of men and women living with HIV (MLHIV and WLHIV) is limited. Objective: To investigate the effects of a long-term multimodal exercise program on the bone mineral density (BMD) of MLHIV and WLHIV. Methods: A retrospective cohort of 39 patients (13 women; 48.4 ± 7.6 y; HIV-infection for 15.5 ± 6.5 y; combined antiretroviral therapy for 12.2 ± 7.0 y) performed a multimodal exercise program (60-min sessions of aerobic, resistance, and flexibility exercises performed 3 times/week for 9–106 months). MLHIV and WLHIV were allocated into groups showing either advanced osteopenia/osteoporosis or normal BMD (+ or −). Results: MLHIV+ increased BMD at the femoral neck, total femur, and lumbar spine (∼3–4%) compared to MLHIV− (p ≤ 0.03). Changes in whole-body BMD were similar between MLHIV groups (p = 0.55). WLHIV+ exhibited higher loss of BMD at the femoral neck (∼6%) than WLHIV− (p = 0.04), whereas reductions in the whole-body, total femur, and lumbar spine (∼3–5%) were similar between groups (p ≥ 0.25). Among men, changes in femoral neck BMD were inversely correlated to femoral neck T-score (r = −0.62; p

Weight loss after bariatric surgery in obesity improves vascular function and metabolic/inflammatory profiles and reduces cardiovascular mortality but there are limited data on the effects of weight regain on vascular health. We compared the metabolic/inflammatory profiles, oxidative status, and vascular function of post-bariatric patients with a high ratio of weight regain (RWR) vs. non-surgical controls. Thirty-two post-bariatric patients [Roux-en-Y gastric bypass; aged = 44 ± 8 years, BMI = 40.1 ± 7.7 kg/m2, and RWR = 58.7 ± 24.3%] and thirty controls that were BMI-, age-, and gender-matched entered the study. We collected clinical data, metabolic/inflammatory/oxidative stress circulating biomarkers, and endothelial/microvascular reactivity through Venous occlusion plethysmography and Laser speckle contrast imaging. The bariatric group exhibited lower neck circumference, fasting glucose, and triglycerides than the non-surgical group, while HDL-cholesterol was higher in the bariatric group (p < 0.001). There was no significant difference between groups for endothelial/microvascular reactivities (p ≥ 0.06). Resistin, leptin, endothelin-1, soluble forms of intercellular cell adhesion molecule-1 and vascular cell adhesion molecule-1, tumor necrosis factor-α, and thiobarbituric acid reactive substances did not differ significantly between groups (p ≥ 0.09) either. The adiponectin level was higher in the bariatric compared to the non-surgical group, while interleukin-6 was lower in the bariatric group (p < 0.001). Despite the fact that endothelial/microvascular functions were not significantly different between groups, post-bariatric patients present partially preserved metabolic/inflammatory benefits even with high RWR.

Background People living with HIV (PLHIV) present impaired muscle metaboreflex, which may lead to exercise intolerance and increased cardiovascular risk. The muscle metaboreflex adaptations to exercise training in these patients are unknown. The present study aims to investigate the effects of a supervised multimodal exercise training on hemodynamic and autonomic responses to muscle metaboreflex activation in PLHIV. Methods and design In this randomized clinical trial protocol, 42 PLHIV aged 30–50 years will be randomly assigned at a ratio of 1:1 into an intervention or a control group. The intervention group will perform exercise training (3x/week during 12 weeks) and the control group will remain physically inactive. A reference group composed of 21 HIV-uninfected individuals will be included. Primary outcomes will be blood pressure and heart rate variability indices assessed during resting, mental stress, and activation of muscle metaboreflex by a digital sphygmomanometer and a heart rate monitor; respectively. Mental stress will be induced by the Stroop Color-Word test and muscle metaboreflex will be activated through a post-exercise circulatory arrest (PECA) protocol, being the latter performed without and with the application of a capsaicin-based analgesic balm in the exercised limb. Secondary outcomes will be heart rate, peripheral vascular resistance, stroke volume, cardiac output, blood lactate, anthropometric markers and handgrip maximal voluntary contraction. The intervention and control groups of PLHIV will be evaluated at baseline and after the intervention, while the HIV-uninfected reference group only at baseline. Discussion The findings of the present study may help to elucidate the muscle metaboreflex adaptations to exercise training in PLHIV. Trial registration This study will be performed at University of Rio de Janeiro State following registration at ClinicalTrials.gov as NCT04512456 on August 13, 2020.

Introduction: Combination antiretroviral therapy (cART) substantially extended the life of people living with HIV (PLHIV). However, prolonged HIV infection and cART increase the risk of comorbidities accelerating age-related muscle, bone, and vascular disorders. This cross-sectional study compared muscle mass and strength, bone mineral density (BMD), and vascular function in middle-aged PLHIV treated with cART vs. non-infected age-matched and older controls. Methods: After careful screening for secondary diseases and medications, body composition, muscular and vascular function were assessed in 12 PLHIV (43.9±8.7 yrs old; HIV-infection for 16.2±8.6 yrs; on cART for 11.6±9.2 yrs), 12 age-matched (CONT, 43.2±8.5 yrs old), and 12 older (OLDER, 74.4±8.3 yrs old) controls through dual x-ray absorptiometry, isokinetic dynamometry, and venous occlusion plethysmography, respectively. Results: PLHIV and CONT showed similar relative muscle mass (65.3±8.0 vs. 66.9±7.3%, respectively; P= 0.88) and strength (160.7±53.9 vs. 152.0±52.9 N.m−1, respectively; P= 0.90), which were greater than OLDER (80.6±18.8 N.m−1; P= 0.001). Total BMD was similar in PLHIV (1.04±0.13 g.cm−2) and OLDER (1.00±0.15 g.cm−2, P= 0.86), and both groups presented lower values than CONT (1.20±0.13 g.cm−2, P< 0.01). No significant difference across groups was detected for macrovascular reactivity (P= 0.32). Conclusion: Age-related osteopenia might be accelerated in middle-aged PLHIV on prolonged cART, as their BMD approached values found in older adults. On the other hand, muscle mass, isokinetic strength, and vasodilation capacity were similar in PLHIV and age-matched uninfected controls.

Background: Gains in muscle mass and strength have been documented in exercise training with blood flow restriction (BFR). However, the impact of retrograde blood flow during BFR training on vascular health remains unclear. The present study designed a protocol to evaluate the acute effects of exercise performed with different levels of BFR on vascular reactivity and biomarkers of endothelial function, oxidative stress, and muscle hypertrophy in young and older individuals. Methods and study design: Sixty-eight physically inactive eutrophic men [34 young (18–25-yrs old) and 34 elderly (≥65-yrs old)] will be included in the study. Subjects will undergo three experimental protocols: a) control (ExCON) – handgrip exercise with intensity of 30% of the maximum voluntary contraction (MVC); b) blood flow restriction (ExBFR) – handgrip exercise with a resistance of 30% of the MVC with low level of BFR [80% of arterial occlusion pressure at rest (rAOP)]; and c) arterial occlusion pressure (ExAOP) – handgrip exercise with a resistance of 30% of the MVC with high level of BFR (120% of rAOP). Primary outcomes will be: a) vascular reactivity assessed by venous occlusion plethysmography; b) endothelial function (nitric oxide and apoptotic endothelial micro particles; c) oxidative stress (thiobarbituric acid reactive substances). Growth hormone and lactate concentration will be measured as secondary outcomes reflecting the hypertrophic drive and metabolic stress, respectively. Discussion: The findings of the present study may help to elucidate the age-related impacts of BFR training on the vascular health.

Objective: Blood flow restriction training (BFRT) has been proposed to induce muscle hypertrophy, but its safety remains controversial as it may increase mean arterial pressure (MAP) due to muscle metaboreflex activation. However, BFR training also causes metabolite accumulation that may desensitize type III and IV nerve endings, which trigger muscle metaboreflex. Then, we hypothesized that a period of BFR training would result in blunted hemodynamic activation during muscle metaboreflex.Methods: 17 young healthy males aged 18–25 yrs enrolled in this study. Hemodynamic responses during muscle metaboreflex were assessed by means of postexercise muscle ischemia (PEMI) at baseline (T0) and after 1 month (T1) of dynamic BFRT. BFRT consisted of 3-min rhythmic handgrip exercise applied 3 days/week (30 contractions per minute at 30% of maximum voluntary contraction) in the dominant arm. On the first week, the occlusion was set at 75% of resting systolic blood pressure (always obtained after 3 min of resting) and increased 25% every week, until reaching 150% of resting systolic pressure at week four. Hemodynamic measurements were assessed by means of impedance cardiography.Results: BFRT reduced MAP during handgrip exercise (T1: 96.3 ± 8.3 mmHg vs. T0: 102.0 ± 9.53 mmHg, p = 0.012). However, no significant time effect was detected for MAP during the metaboreflex activation (P > 0.05). Additionally, none of the observed hemodynamic outcomes, including systemic vascular resistance (SVR), showed significant difference between T0 and T1 during the metaboreflex activation (P > 0.05).Conclusion: BFRT reduced blood pressure during handgrip exercise, thereby suggesting a potential hypotensive effect of this modality of training. However, MAP reduction during handgrip seemed not to be provoked by lowered metaboreflex activity.