Basic science behind the cardiovascular benefits of exercise

Cardiorespiratory fitness is a strong predictor of cardiovascular (CV) disease and all-cause mortality, with increases in cardiorespiratory fitness associated with corresponding decreases in CV disease risk. The effects of exercise upon the myocardium and vascular system are dependent upon the frequency, intensity and duration of the exercise itself. Following a prolonged period (≥6 months) of regular intensive exercise in previously untrained individuals, resting and submaximal exercising heart rates are typically 5–20 beats lower, with an increase in stroke volume of ∼20% and enhanced myocardial contractility. Structurally, all four heart chambers increase in volume with mild increases in wall thickness, resulting in greater cardiac mass due to increased myocardial cell size. With this in mind, the present paper aims to review the basic science behind the CV benefits of exercise. Attention will be paid to understanding (1) the relationship between exercise and cardiac remodelling; (2) the cardiac cellular and molecular adaptations in response to exercise, including the examination of molecular mechanisms of physiological cardiac growth and applying these mechanisms to identify new therapeutic targets to prevent or reverse pathological remodelling and heart failure; and (3) vascular adaptations in response to exercise. Finally, this review will briefly examine how to optimise the CV benefits of exercise by considering how much and how intense exercise should be

Basic science behind the cardiovascular benefits of exercise

Cardiorespiratory fitness is a strong predictor of cardiovascular (CV) disease and all-cause mortality, with increases in cardiorespiratory fitness associated with corresponding decreases in CV disease risk. The effects of exercise upon the myocardium and vascular system are dependent upon the frequency, intensity and duration of the exercise itself. Following a prolonged period (≥6 months) of regular intensive exercise in previously untrained individuals, resting and submaximal exercising heart rates are typically 5–20 beats lower, with an increase in stroke volume of ∼20% and enhanced myocardial contractility. Structurally, all four heart chambers increase in volume with mild increases in wall thickness, resulting in greater cardiac mass due to increased myocardial cell size. With this in mind, the present paper aims to review the basic science behind the CV benefits of exercise. Attention will be paid to understanding (1) the relationship between exercise and cardiac remodelling; (2) the cardiac cellular and molecular adaptations in response to exercise, including the examination of molecular mechanisms of physiological cardiac growth and applying these mechanisms to identify new therapeutic targets to prevent or reverse pathological remodelling and heart failure; and (3) vascular adaptations in response to exercise. Finally, this review will briefly examine how to optimise the CV benefits of exercise by considering how much and how intense exercise should be

Basic science behind the cardiovascular benefits of exercise

Cardiorespiratory fitness is a strong predictor of cardiovascular (CV) disease and all-cause mortality, with increases in cardiorespiratory fitness associated with corresponding decreases in CV disease risk. The effects of exercise upon the myocardium and vascular system are dependent upon the frequency, intensity and duration of the exercise itself. Following a prolonged period (≥6 months) of regular intensive exercise in previously untrained individuals, resting and submaximal exercising heart rates are typically 5–20 beats lower, with an increase in stroke volume of ∼20% and enhanced myocardial contractility. Structurally, all four heart chambers increase in volume with mild increases in wall thickness, resulting in greater cardiac mass due to increased myocardial cell size. With this in mind, the present paper aims to review the basic science behind the CV benefits of exercise. Attention will be paid to understanding (1) the relationship between exercise and cardiac remodelling; (2) the cardiac cellular and molecular adaptations in response to exercise, including the examination of molecular mechanisms of physiological cardiac growth and applying these mechanisms to identify new therapeutic targets to prevent or reverse pathological remodelling and heart failure; and (3) vascular adaptations in response to exercise. Finally, this review will briefly examine how to optimise the CV benefits of exercise by considering how much and how intense exercise should be

Basic science behind the cardiovascular benefits of exercise

Cardiorespiratory fitness is a strong predictor of cardiovascular (CV) disease and all-cause mortality, with increases in cardiorespiratory fitness associated with corresponding decreases in CV disease risk. The effects of exercise upon the myocardium and vascular system are dependent upon the frequency, intensity and duration of the exercise itself. Following a prolonged period (≥6 months) of regular intensive exercise in previously untrained individuals, resting and submaximal exercising heart rates are typically 5–20 beats lower, with an increase in stroke volume of ∼20% and enhanced myocardial contractility. Structurally, all four heart chambers increase in volume with mild increases in wall thickness, resulting in greater cardiac mass due to increased myocardial cell size. With this in mind, the present paper aims to review the basic science behind the CV benefits of exercise. Attention will be paid to understanding (1) the relationship between exercise and cardiac remodelling; (2) the cardiac cellular and molecular adaptations in response to exercise, including the examination of molecular mechanisms of physiological cardiac growth and applying these mechanisms to identify new therapeutic targets to prevent or reverse pathological remodelling and heart failure; and (3) vascular adaptations in response to exercise. Finally, this review will briefly examine how to optimise the CV benefits of exercise by considering how much and how intense exercise should be

Thermoregulatory responses to combined moderate heat stress and hypoxia

Objective: The aim of this study was to examine the cutaneous vascular and sudomotor responses to combined moderate passive heat stress and normobaric hypoxia. Method: Thirteen healthy young males, dressed in a water-perfused suit, underwent passive heating (Δcore temperature ~0.7 °C) twice (NORMOXIA; 20.9% O2 and HYPOXIA; 13% O2). Chest and forearm skin blood flow (SkBF; laser Doppler flux), local sweat rate (SR; capacitance hygrometry) and core (intestinal pill) and skin temperatures, were recorded. Results: HYPOXIA reduced baseline oxygen saturation (98±1 vs. 89±6%, P<0.001) and elevated chest (P=0.03) and forearm SkBF (P=0.03) and HR (64±9 vs. 69±8 beats.min-1, P<0.01). During heating, mean body temperature (T ̅BODY) thresholds for SkBF (P=0.41) and SR (P=0.28) elevations were not different between trials. The SkBF: T ̅BODY linear sensitivity during the initial phase of heating was lower at the Chest (P=0.035) but not different at the forearm (P=0.17) during HYPOXIA. With increasing levels of heating chest SkBF was not different (P=0.55) but forearm SkBF was lower on the forearm (P<0.01) during HYPOXIA. Chest (P=0.85) and forearm (P=0.79) SR:T ̅BODY linear sensitivities were not different between trials. Conclusion: Whilst sudomotor responses and the initiation of cutaneous blood flow elevations are unaffected, hypoxia differentially effects regional SkBF responses during moderate passive heating

Parental views of children's physical activity: a qualitative study with parents from multi-ethnic backgrounds living in England

Background: Guidelines recommend children and young people participate in at least 60 min of physical activity (PA) every day, however, findings from UK studies show PA levels of children vary across ethnic groups. Since parents play an instrumental role in determining children’s PA levels, this article aims to explore parental views of children’s PA in a multi-ethnic sample living in a large city in the North-West of England. Methods: Six single-ethnic focus groups were conducted with 36 parents of school-aged children (4 to 16 years) with a predominantly low socio-economic status (SES). Parents self-identified their ethnic background as Asian Bangladeshi (n = 5), Black African (n = 4), Black Somali (n = 7), Chinese (n = 6), White British (n = 8) and Yemeni (n = 6). Focus group topics included understanding of PA, awareness of PA guidelines, knowledge of benefits associated with PA and perceived influences on PA in childhood. Data were analysed thematically using QSR NVivo 9.0. Results: Parents from all ethnic groups valued PA and were aware of its benefits, however they lacked awareness of PA recommendations, perceived school to be the main provider for children’s PA, and reported challenges in motivating children to be active. At the environmental level, barriers to PA included safety concerns, adverse weather, lack of resources and lack of access. Additional barriers were noted for ethnic groups from cultures that prioritised educational attainment over PA (Asian Bangladeshi, Chinese, Yemeni) and with a Muslim faith (Asian Bangladeshi, Black Somali, Yemeni), who reported a lack of culturally appropriate PA opportunities for girls. Conclusion: Parents from multi-ethnic groups lacked awareness of children’s PA recommendations and faced barriers to promoting children’s PA out of school, with certain ethnic groups facing additional barriers due to cultural and religious factors. It is recommended children’s PA interventions address influences at all socio-ecological levels, and account for differences between ethnic groups

Repeated ischaemic preconditioning: A novel therapeutic intervention and potential underlying mechanisms.

Ischaemic preconditioning (IPC) refers to the phenomenon that short periods of cyclical tissue ischaemia confer subsequent protection against ischaemia-induced injury. As a consequence, IPC can ameliorate the myocardial damage following infarction and reduce infarct size. The ability of IPC to confer remote protection makes IPC a potentially feasible cardioprotective strategy. In this review, we discuss the concept that repeatedly exposing tissue to IPC may increase the "dose" of protection, and subsequently lead to enhanced protection against ischaemia-induced myocardial injury. This may be relevant for clinical populations, who demonstrate attenuated efficacy of IPC to prevent or attenuate ischaemic injury (and therefore myocardial infarct size). Furthermore, episodic IPC facilitates repeated exposure to local (e.g. shear stress) and systemic (e.g. hormones, cytokines, blood-borne substances) stimuli, which may induce improvement in vascular function and health. Such adaptation may contribute to prevention of cardio- and cerebro-vascular events. The clinical benefits of repeated IPC may, therefore, result from both the prevention of ischaemic events and attenuation of their consequences. We provide an overview of the literature pertaining to the impact of repeated IPC on cardiovascular function, related to both local and or remote adaptation, as well as potential clinical implications. This article is protected by copyright. All rights reserved

Historical reviews of the assessment of human cardiovascular function: interrogation and understanding of the control of skin blood flow.

Several techniques exist for the determination of skin blood flow that have historically been used in the investigation of thermoregulatory control of skin blood flow, and more recently, in clinical assessments or as an index of global vascular function. Skin blood flow measurement techniques differ in their methodology and their strengths and limitations. To examine the historical development of techniques for assessing skin blood flow by describing the origin, basic principles, and important aspects of each procedure and to provide recommendations for best practise. Venous occlusion plethysmography was one of the earliest techniques to intermittently index a limb's skin blood flow under conditions in which local muscle blood flow does not change. The introduction of laser Doppler flowmetry provided a method that continuously records an index of skin blood flow (red cell flux) (albeit from a relatively small skin area) that requires normalisation due to high site-to-site variability. The subsequent development of laser Doppler and laser speckle imaging techniques allows the mapping of skin blood flow from larger surface areas and the visualisation of capillary filling from the dermal plexus in two dimensions. The use of iontophoresis or intradermal microdialysis in conjunction with laser Doppler methods allows for the local delivery of pharmacological agents to interrogate the local and neural control of skin blood flow. The recent development of optical coherence tomography promises further advances in assessment of the skin circulation via three-dimensional imaging of the skin microvasculature for quantification of vessel diameter and vessel recruitment

Do acute effects of exercise on vascular function predict adaptation to training?

PURPOSE: No previous study has explored the importance of exercise-induced changes in vascular function to prolonged adaptations. Therefore, the purpose was to explore the within-subject relationship between the acute post-exercise change in brachial artery endothelial function (flow-mediated dilation, FMD) and the change in resting FMD after a 2-week exercise training in healthy volunteers. METHODS: Twenty one healthy, young men (24 ± 5 years) underwent assessment of brachial artery FMD using high-resolution ultrasound before and after 30-min of moderate-intensity cycle exercise (80% maximal heart rate). Subsequently, subjects performed five 30-min cycle exercise bouts at 80% maximal heart rate across a 2-week period, followed by repeat assessment of resting brachial FMD post-training. RESULTS: Correcting for changes in diameter and shear, FMD did not change after the initial exercise bout (P = 0.26). However, a significant correlation was found between post-exercise changes in FMD and adaptation in resting FMD after training (r = 0.634, P = 0.002), where an acute decrease in post-exercise FMD resulted in a decrease in baseline FMD after 2 weeks and vice versa. We also found a positive correlation between antegrade shear rate during exercise and change in FMD% after acute exercise and after exercise training (r = 0.529 and 0.475, both P < 0.05). CONCLUSION: Our findings suggest that acute post-exercise changes in vascular function are related to changes in resting FMD after a 2-week endurance exercise training period in healthy men, an effect that may be related to exercise-induced increases in antegrade shear rate. This provides further insight into the relevance of acute changes in shear and FMD for subsequent adaptation

Impact of eight weeks of repeated ischaemic preconditioning on brachial artery and cutaneous microcirculatory function in healthy males

Background Ischaemic preconditioning has well-established cardiac and vascular protective effects. Short interventions (one week) of daily ischaemic preconditioning episodes improve conduit and microcirculatory function. This study examined whether a longer (eight weeks) and less frequent (three per week) protocol of repeated ischaemic preconditioning improves vascular function. Methods Eighteen males were randomly allocated to either ischaemic preconditioning (22.4 ± 2.3 years, 23.7 ± 3.1 kg/m2) or a control intervention (26.0 ± 4.8 years, 26.4 ± 1.9 kg/m2). Brachial artery endothelial-dependent (FMD), forearm cutaneous microvascular function and cardiorespiratory fitness were assessed at zero, two and eight weeks. Results A greater improvement in FMD was evident following ischaemic preconditioning training compared with control at weeks 2 (2.24% (0.40, 4.08); p=0.02) and 8 (1.11% (0.13, 2.10); p=0.03). Repeated ischaemic preconditioning did not change cutaneous microcirculatory function or fitness. Conclusions These data indicate that a feasible and practical protocol of regular ischaemic preconditioning episodes improves endothelial function in healthy individuals within two weeks, and these effects persist following repeated ischaemic preconditioning for eight weeks