Emerging data indicate a substantial decrease in global physical activity levels during the period of social isolation adopted worldwide to contain the spread of the coronavirus disease 2019 (COVID-19). Confinement-induced decreases in physical activity levels and increases in sedentary behavior may provoke a rapid deterioration of cardiovascular health and premature deaths among populations with increased cardiovascular risk. Even short-term (1–4 wk) inactivity has been linked with detrimental effects in cardiovascular function and structure and increased cardiovascular risk factors. In this unprecedented and critical scenario, home-based physical activity programs arise as a clinically relevant intervention to promote health benefits to cardiac patients. Many studies have demonstrated the feasibility, safety, and efficacy of different models of home-based exercise programs in the primary and secondary prevention of cardiovascular diseases and major cardiovascular events among different populations. This body of knowledge can inform evidence-based policies to be urgently implemented to counteract the impact of increased physical inactivity and sedentary behavior during the COVID-19 outbreak, thereby alleviating the global burden of cardiovascular disease.

Cardiovascular disease (CVD) is the primary cause of mortality worldwide. Cardiac autonomic dysfunction seems to be related to the genesis of several CVDs and is also linked to the increased risk of mortality in CVD patients. The quantification of heart rate decrement after exercise - known as heart rate recovery (HRR) - is a simple tool for assessing cardiac autonomic activity in healthy and CVD patients. Furthermore, since The Cleveland Clinic studies, HRR has also been used as a powerful index for predicting mortality. For these reasons, in recent years, the scientific community has been interested in proposing methods and protocols to investigate HRR and understand its underlying mechanisms. The aim of this review is to discuss current knowledge about HRR, including its potential primary and secondary physiological determinants, as well as its role in predicting mortality. Published data show that HRR can be modelled by an exponential curve, with a fast and a slow decay component. HRR may be influenced by population and exercise characteristics. The fast component mainly seems to be dictated by the cardiac parasympathetic reactivation, probably promoted by the deactivation of central command and mechanoreflex inputs immediately after exercise cessation. On the other hand, the slow phase of HRR may be determined by cardiac sympathetic withdrawal, possibly via the deactivation of metaboreflex and thermoregulatory mechanisms. All these pathways seem to be impaired in CVD, helping to explain the slower HRR in such patients and the increased rate of mortality in individuals who present a slower HRR.

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Blood flow restriction training (BFRT) is an increasingly widespread method of exercise that involves imposed restriction of blood flow to the exercising muscle. Blood flow restriction is achieved by inflating a pneumatic pressure cuff (or a tourniquet) positioned proximal to the exercising muscle before, and during, the bout of exercise (i.e., ischemic exercise). Low-intensity BFRT with resistance training promotes comparable increases in muscle mass and strength observed during high-intensity exercise without blood flow restriction. BFRT has expanded into the clinical research setting as a potential therapeutic approach to treat functionally impaired individuals, such as the elderly, and patients with orthopedic and cardiovascular disease/conditions. However, questions regarding the safety of BFRT must be fully examined and addressed before the implementation of this exercise methodology in the clinical setting. In this respect, there is a general concern that BFRT may generate abnormal reflex-mediated cardiovascular responses. Indeed, the muscle metaboreflex is an ischemia-induced, sympathoexcitatory pressor reflex originating in skeletal muscle, and the present review synthesizes evidence that BFRT may elicit abnormal cardiovascular responses resulting from increased metaboreflex activation. Importantly, abnormal cardiovascular responses are more clearly evidenced in populations with increased cardiovascular risk (e.g., elderly and individuals with cardiovascular disease). The evidence provided in the present review draws into question the cardiovascular safety of BFRT, which clearly needs to be further investigated in future studies. This information will be paramount for the consideration of BFRT exercise implementation in clinical populations.

Introduction:The acute blood pressure (BP) decrease is greater after evening than morning exercise, suggesting that evening training may have a greater hypotensive effect. Objective:To compare the hypotensive effect of aerobic training performed in the morning versus evening in treated hypertensives. Methods: Fifty treated hypertensive men were randomly allocated to 3 groups: morning training (MT); evening training (ET); and control (C). Training groups cycled for 45min at moderate-intensity (progressing from the heart rate of the anaerobic threshold to 10% below the heart rate of the respiratory compensation point), while C stretched for 30 min. Interventions were conducted 3 times/week for 10 weeks. Clinic and ambulatory BP, hemodynamic, and autonomic mechanisms were evaluate d before and after the interventions. Clinic assessments were performed in the morning (7-9a.m.) and evening (6-8p.m.). Between-within ANOVAs were used (P≤0.05). Results: Only ET decreased clinic systolic BP differently from C and MT (morning assessment -5±6 mmHg and evening assessment -8±7 mmHg, P<0.05). Only ET reduced 24h and asleep diastolic BP differently from C and MT (-3±5 and -3±4 mmHg, respectively, P<0.05). Systemic vascular resistance (SVR) decreased from C only in ET (P=0.03). Vasomotor sympathetic modulation decreased (P=0.001) and baroreflex sensitivity (P<0.02) increased from C in both training groups with greater changes in ET than MT. Conclusions: In treated hypertensive men, aerobic training performed in the evening decreased clinic and ambulatory BP, due to reductions in SVR and vasomotor sympathetic modulation. Aerobic training conducted at both times of day increases baroreflex sensitivity, but with greater after ET.

Subjects with PD demonstrated blunted metabolic and cardiovascular responses to submaximal and maximal exercise tests, especially at intensities above AT, which are in line with autonomic disturbances present in patients with PD. Future studies need to determine how this affects performance, participation, and responses of these patients to exercise training at different intensities.

Post-exercise hypotension (PEH) is a clinically relevant phenomenon that has been widely investigated. However, the characteristics of study designs, such as familiarization to blood pressure measurements, duration of PEH assessments or strategies to analyze PEH present discrepancies across studies. Thus identifying key points to standardize across PEH studies is necessary to help researchers to build stronger study designs, to facilitate comparisons across studies, and to avoid misinterpretations of results. The goal of this narrative review of methods used in PEH studies was therefore to gather and find possible influencers in the characteristics of study design and strategies to analyze blood pressure. Data found in this review suggest that PEH studies should have at least two familiarization screening visits, and should assess blood pressure for at least 20 min, but preferably for 120 min, during recovery from exercise. Another important aspect is the strategy to analyze PEH, which may lead to different interpretations. This information should guide a priori study design decisions.