Cómo el ejercicio mejora la salud cardiovascular según la medicina

Authors: Gao Jinxiong, Chief Physician at the Cardiac Center (Cardiology) of Beijing Thoracic Hospital, affiliated with Beijing University of Medicine. The lack of physical activity (PA) and increased sedentary behavior (SB) are independent risk factors predicting poor cardiovascular health. Cardiovascular diseases (CVD) are one of the leading causes of morbidity and mortality worldwide, with an estimated 18.6 million deaths in 2019, accounting for 32% of global deaths. Despite numerous public health efforts, the World Health Organization estimates that 27.5% of adults do not meet the recommended level of physical activity, a percentage that has remained relatively constant since 2001.

Evidence shows that regular exercise serves as a protective factor for health. Even a slight increase in physical activity can significantly reduce the risk of cardiovascular diseases, diabetes, hypertension, obesity, and premature death. Meeting the WHO guidelines for physical activity can lower cardiovascular mortality by approximately 30% and overall mortality by around 29%. Encouraging movement and reducing sedentary behavior are vital for health benefits. Increasing activity and decreasing sedentary time, as well as participating in organized exercise programs, should be prescribed as essential practices.

Physiological and cardiovascular adaptations occur with exercise. The benefits of exercise, particularly the improvement in cardiorespiratory health (CRF), are mediated by various mechanisms. Sustained aerobic exercise is characterized by increased metabolic demands of skeletal muscles, where oxygen consumption (VO2) is the most precise measure of performance. This increase in oxygen consumption can be achieved by enhancing cardiac output and muscle oxygen uptake, known as exercise-induced cardiac remodeling, triggered by hemodynamic stress.

These changes often accompany increased filling during early diastole, due to enhanced venous return from muscle contraction, leading to greater stroke volume and increased cardiac output at any given heart rate. Such adaptations alleviate myocardial changes related to age, reducing compliance and stiffness of the left ventricle, factors that could raise heart failure risk. Additionally, aerobic training increases parasympathetic nervous system tone and vagal nerve activity at rest, decreasing resting heart rate and peripheral vascular resistance, subsequently lowering systemic blood pressure.

The arterial system responds favorably to regular aerobic exercise. During exercise, capillaries and small arteries dilate in response to various vasodilatory signals. Over time, this promotes vascular restructuring, increasing capillary density and enhancing blood flow to skeletal muscles. Similar mechanisms occur in the coronary system, boosting blood flow to the myocardium and improving ischemic tolerance. Exercise can increase circulating volume by up to 25%, enhancing red blood cell capacity and hemoglobin content.

Specific physiological adaptations also occur with resistance training, commonly known as "strength training." Progressive resistance training significantly contributes to skeletal muscle hypertrophy through increased recruitment and activation of motor units. This type of training relates to increased muscle strength and bone density, especially in lower limb muscles. The cardiovascular adaptations resulting from resistance exercise differ significantly from those of aerobic activity. Changes in central hemodynamics lead to reduced systolic volume and cardiac output during resistance training.

The impact and benefits of exercise in preventing metabolic diseases of the heart are significant. Regular physical activity improves cardiovascular health, reduces heart disease risk, and manages risk factors like hypertension, diabetes, and obesity. Exercise strengthens the cardiac muscle, enhances blood circulation, and contributes to better cholesterol and blood sugar control. Therefore, incorporating exercise into daily routines is crucial for maintaining heart health and preventing metabolic diseases.

The latest guidelines from the World Health Organization (WHO) and the 2018 Physical Activity Guidelines (PAG) propose recommendations for the types and amounts of exercise that can enhance public health outcomes. Both organizations suggest engaging in at least 150 to 300 minutes of moderate-intensity aerobic exercise or a combination of moderate and high-intensity activity each week. For additional health benefits, especially weight management, exceeding 300 minutes weekly is recommended.

The lack of physical activity and increased sedentary behaviors predict poor cardiovascular health. Regular physical activity leads to physiological adaptations, including exercise-induced cardiac remodeling and vascular changes that enhance CRF and lower cardiovascular disease risk. Regular physical activity can significantly improve glucose control, blood pressure, and lipid levels, thereby reducing the risk of coronary disease, heart failure and overall mortality. Due to the significant benefits in cardiovascular disease prevention and management, regular exercise participation should be encouraged.