How to Improve Cardiovascular Health Through Exercise Techniques

Author: Gao Jinxiong, Chief Physician of the Cardiac Center (Cardiology) at the Beijing Chest Hospital affiliated with Capital Medical University. Cardiovascular disease is a top worldwide killer; the WHO advises 150-300 minutes of weekly exercise for better health. Cardiovascular disease (CVD) is a leading cause of morbidity and mortality worldwide, with an estimated 18.6 million deaths in 2019, accounting for 32% of global deaths. A lack of physical activity (PA) and increased sedentary behavior (SB) are major independent predictors of poor cardiovascular health and reversible risk factors for many chronic diseases, including cardiovascular disease. Among the 57 million deaths globally in 2008, over 5.3 million were attributed to insufficient engagement in physical activity and increased sedentary behavior. Despite significant public health efforts, the World Health Organization estimates that 27.5% of adults do not meet the recommended levels of physical activity, and this rate has remained relatively unchanged since 2001; additionally, participation rates are lower among women, ethnic minorities, individuals of lower socioeconomic status, and the elderly.

Evidence indicates that regular exercise serves as a protective measure for both primary and secondary health. From a population health perspective, even a slight increase in regular physical activity (PA) can significantly reduce the risk of cardiovascular diseases, diabetes, hypertension, obesity, and premature death. In fact, both aerobic exercises and resistance training can provide substantial benefits in lowering the risk of cardiovascular diseases, even when the levels are below the current recommended targets. Adhering to the World Health Organization's physical activity guidelines reduces cardiovascular disease mortality by approximately 30% and all-cause mortality by about 29%. More broadly, regardless of the type of physical activity—such as active commuting, low-intensity walking, or taking stairs—doing more and sitting less leads to significant health benefits. In this context, engaging in more physical activity and participating in an organized exercise program should be a fitness prescription that everyone can access and adhere to rigorously.

Adaptation of Physiological and Cardiovascular Diseases in Sports. The benefits of exercise, particularly the improvement of cardiovascular fitness (CRF), are mediated by various mechanisms, many of which involve the cardiovascular system. The hallmark of sustained aerobic exercise is the increased metabolic demand of skeletal muscle, which is most accurately measured by the increase in oxygen consumption (VO2), essential for muscle power generation and bodily stability. According to the Fick equation, the increase in oxygen consumption during exercise can be achieved through an increase in cardiac output and muscle oxygen uptake. In the context of habitual aerobic exercise training, cardiac adaptations can enhance optimal cardiac output. This process is commonly referred to as exercise-induced cardiac remodeling, triggered by hemodynamic stress, which can be simplified to the increase of cardiac volume flow and elevated cardiac afterload. Exercise-induced cardiac remodeling (EICR) is a complex process that includes enhanced myocardial contractility as well as increases in left ventricular (LV) mass and end-diastolic volume. Specifically, habitual aerobic exercise leads to a beneficial form of myocardial hypertrophy characterized by an increase in left ventricular diastolic chamber volume and wall thickness while preserving or improving contractility.

These changes are typically accompanied by enhanced early diastolic filling, due to increased venous return from muscle contractions, leading to an increased stroke volume and thereby increasing cardiac output at any given heart rate. These adaptations are beneficial and have been shown to mitigate age-related myocardial changes, including reductions in left ventricular compliance and stiffness, which may elevate the risk of heart failure (HF). Additionally, aerobic exercise training results in increased parasympathetic and vagal tone under resting conditions, leading to a lower resting heart rate, increased heart rate variability, and reduced peripheral vascular resistance, consequently lowering overall blood pressure (BP).

The arterial vascular system responds positively to habitual aerobic exercise. Capillaries and small arteries dilate during exercise in response to various vasodilatory signals, including nitric oxide, lactic acid, adenosine, carbon dioxide, and hypoxia. Over time, this promotes vascular structural remodeling characterized by an increase in capillary density, leading to an overall increase in skeletal muscle blood flow and enhanced tissue perfusion. Similar mechanisms occur throughout the coronary system, increasing blood flow to the myocardium and enhancing tolerance to ischemic and reperfusion injury. Moreover, exercise has been shown to increase circulatory blood volume by up to 25%, which includes increased red blood cell volume and hemoglobin content, thereby enhancing the delivery of oxygen and nutrients. Finally, aerobic exercise contributes to improved endothelial function by enhancing the bioavailability of nitric oxide and reducing inflammatory markers.

Specific physiological adaptations also occur in resistance training, which is also known as strength training. It is widely believed that progressive resistance training leads most notably to skeletal muscle hypertrophy. Research indicates that this mechanism occurs through increased participation and activation of skeletal motor units during voluntary contractions. Resistance training is also associated with increases in muscle strength and bone density, particularly in the lower limb muscles, femur, and hip. Additionally, the unique cardiovascular adaptations that occur through resistance exercise are distinctly different from those seen in aerobic exercise. Due to intermittent exertion, there are significant and rapid fluctuations in arterial blood pressure, accompanied by a gradual increase in heart rate and left ventricular hypertrophy. Resistance training has a blood pressure-lowering effect, with a greater reduction observed when larger muscle groups are used. Unlike the peripheral vasodilation that occurs with aerobic training, the hypotension following resistance training is mediated through central hemodynamic changes, primarily by reducing stroke volume and cardiac output.

The impact and benefits of exercise on the prevention of metabolic heart diseases. Guidelines for Physical Activity (PA) and Exercise. The latest public health guidelines from the World Health Organization and the 2018 Physical Activity Guidelines (PAG) from the United States provide recommendations on the types and amounts of exercise needed to improve population health outcomes. Both organizations recommend engaging in at least 150 to 300 minutes of moderate-intensity aerobic activity, or 75 to 150 minutes of vigorous-intensity aerobic activity each week, or a combination of moderate and vigorous activities that equal this amount. For additional health benefits, particularly in weight management, it is advised to exceed 300 minutes of physical activity per week. Furthermore, the guidelines recommend incorporating muscle-strengthening activities that involve all major muscle groups on at least two days each week. Unlike previous guidelines, all forms of completed physical activity contribute to the total recommended activity for the week, regardless of the duration of each specific exercise session. Finally, there is an emphasis on establishing healthy physical activity behaviors early in life. For children aged 6 to 17, it is recommended to engage in at least 60 minutes of moderate to vigorous physical activity daily. Current recommendations for personalized exercise prescriptions provide more specificity in terms of the quality and quantity of exercise, incorporating aerobic activities, muscle strengthening, flexibility, and neuromuscular exercises, all aimed at achieving personal health and cardiovascular fitness goals. Generally, regardless of the type of physical activity performed, everyone should be encouraged to be more active and sit less each day.

Table 1: Effective Interventions for Improving Cardiovascular Disease Prognosis through Physical Activity (PA). Summary. Insufficient physical activity and increased sedentary behavior are independent predictors of poor cardiovascular health and risk factors for cardiovascular diseases. Regular exercise induces physiological adaptations, including exercise-induced cardiac remodeling and changes in the vascular system, which help improve cardiorespiratory fitness (CRF), reduce the risk and mortality associated with cardiovascular diseases, and play an essential role in cardiovascular health. Specifically, regular physical activity can significantly enhance blood sugar control, blood pressure, and lipid levels. Additionally, it substantially lowers the risk of coronary heart disease, heart failure, and all-cause mortality. Therefore, in light of the significant benefits of treatment and prevention for cardiovascular diseases, regular exercise should be encouraged as an important component of cardiovascular health and disease management.