Acute effects of exercise with blood flow restriction on endothelial function in healthy young and older populations: a systematic review / Efeitos agudos do exercício com restrição do fluxo sanguíneo na função endotelial de jovens e idosos saudáveis: uma revisão sistemática

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. (AU)

O objetivo desta revisão foi identificar os efeitos agudos da restrição do fluxo sanguíneo (RFS) com vs. sem exercício na função endotelial de indivíduos saudáveis, bem como as alterações na função endotelial em jovens e idosos após diferentes níveis de RFS vs. fluxo livre. Pesquisas sistemáticas foram realizadas nas bases United States National Library of Medicine (PubMed), Web of Science, Scopus e Cochrane Library até 17 de julho de 2021. Os estudos incluíram indivíduos saudáveis que avaliaram a função endotelial antes e após protocolos experimentais, por meio da dilatação mediada por fluxo. Foi selecionado o total de 4.890 estudos, e foram elegíveis seis de moderada a alta qualidade metodológica (Physioterapy Evidence Database 6 ­ 10 pontos), incluindo 82 indivíduos (24 ­ 68 anos). No geral, a dilatação mediada por fluxo aumentou no braço sem manguito, imediatamente e 15 minutos após o exercício, sem alteração no braço com manguito (RFS de 60 ­ 80 mmHg). Em protocolos sem exercício, pressões do manguito de 25 ­ 30 mmHg aplicadas por 30 minutos não promoveram alterações na função endotelial, enquanto aquelas > 50 mmHg induziram uma atenuação dose-dependente da dilatação mediada por fluxo em indivíduos jovens. Um nível moderado de RFS parece não ter efeito na função endotelial após uma sessão de exercício. Em condições sem exercício, as reduções na dilatação mediada por fluxo parecem resultar do aumento do cisalhamento retrógrado provocado por pressões do manguito ≥ 50 mmHg em jovens, mas não em idosos. O aumento da taxa de cisalhamento anterógrado relacionada ao exercício leva a maior resposta vasodilatadora mediada pelo óxido nítrico. No entanto, a RFS parece atenuar esse efeito em jovens, mas não em . (AU)

Association of physical activity levels and the prevalence of COVID-19-associated hospitalization.

OBJECTIVES: We compared physical activity levels before the outbreak and quarantine measures with COVID-19-associated hospitalization prevalence in surviving patients infected with SARS-CoV-2. Additionally, we investigated the association of physical activity levels with symptoms of the disease, length of hospital stay, and mechanical ventilation. DESIGN: Observational, cross-sectional. METHODS: Between June 2020 and August 2020, we invited Brazilian survivors and fully recovered patients infected with SARS-CoV-2 to respond to an online questionnaire. We shared the electronic link to the questionnaire on the internet. We collected data about clinical outcomes (symptoms, medications, hospitalization, and length of hospital stay) and cofactors, such as age, sex, ethnicity, preexisting diseases, socioeconomic and educational, and physical activity levels using the International Physical Activity Questionnaire (IPAQ short version). RESULTS: Out of 938 patients, 91 (9.7%) were hospitalized due to COVID-19. In a univariate analysis, sex, age, and BMI were all associated with hospitalizations due to COVID-19. Men had a higher prevalence of hospitalization (66.6%, p = 0.013). Patients older than 65 years, obese, and with preexisting disease had a higher prevalence of COVID-19-related hospitalizations. In a multivariate regression model, performance of at least 150 min/wk (moderate) and/or 75 min/wk (vigorous) physical activity was associated with a lower prevalence of hospitalizations after adjustment for age, sex, BMI, and preexisting diseases (PR = 0.657; p = 0.046). CONCLUSIONS: Sufficient physical activity levels were associated with a lower prevalence of COVID-19-related hospitalizations. Performing at least 150 min a week of moderate-intensity, or 75 min a week of vigorous-intensity physical activity was associated with 34.3% reduction in prevalence.

Acute effects of physical exercise with different levels of blood flow restriction on vascular reactivity and biomarkers of muscle hypertrophy, endothelial function and oxidative stress in young and elderly subjects - A randomized controlled protocol.

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.