Exploring the physiological mechanisms of exercise in regulating blood pressure: the hypotensive effects of aerobic training and strength training.

Appropriate exercise can lower blood pressure in patients with hypertension. Numerous experimental reports on the effects of exercise on blood pressure have fully demonstrated this, with the vast majority of studies concluding that exercise can lower blood pressure in patients with hypertension. Exercise training resulted in a decrease in blood pressure in approximately 75% of hypertensive subjects, with an average decrease of about 11 mmHg in systolic blood pressure and 8 mmHg in diastolic blood pressure. The decrease in blood pressure was greater in women than in men, and the decrease in blood pressure was more significant in middle-aged hypertensive patients than in young people and the elderly.

As research into exercise intervention for hypertension deepens, researchers have begun to study the form, intensity, frequency, and duration of exercise in detail, striving to combine the most suitable parameters to create an optimal treatment plan for hypertension, thus serving as an exercise prescription for the condition. The main focus is on two types of exercise: aerobic exercise and strength training.

Aerobic exercise refers to a type of exercise that is relatively long-lasting, low-intensity, involves large muscle groups, and primarily utilizes aerobic metabolism. Aerobic exercises such as brisk walking, cycling, Tai Chi, and swimming have beneficial effects on patients with essential hypertension. Aerobic exercise is currently recognized as a form of exercise for lowering blood pressure, but its mechanisms are not fully understood. Related reports explore the reasons for the decrease in blood pressure from the following aspects:

Central nervous system regulation. Exercise training can regulate the motor centers in the cerebral cortex and subcortex, normalizing their tension and lowering blood pressure. Furthermore, exercise training can regulate the function of the autonomic nervous system, reducing sympathetic nerve excitability, increasing vagal nerve excitability, relieving small artery spasm, and lowering blood pressure. Adjustment of hormone secretion levels. It decreases the secretion of hormones that raise blood pressure, such as catecholamines and serotonin. Simultaneously, it increases the secretion of hormones that lower blood pressure, such as prostaglandins and plasma atrial natriuretic peptide.

It regulates the levels of bioactive substances produced by vascular endothelial cells, such as plasma endothelin and nitric oxide. Long-term aerobic exercise can increase nitric oxide secretion and inhibit endothelin secretion, which helps reduce vascular tone and peripheral resistance. Aerobic exercise has a significant effect on hypertension-related risk factors, such as weight loss and improved glucose and lipid metabolism. It also causes adaptive changes in vascular structure. Data shows that muscle blood vessels undergo structural changes after exercise training, including increased vessel length, increased cross-sectional area or diameter, and angiogenesis.

This structural change can improve pathological vascular remodeling in hypertension, thereby lowering blood pressure by reducing peripheral resistance. It also improves risk factors for hypertension. Exercise training can improve blood circulation, control weight, lower blood lipids, promote metabolism, enhance the body's stress response, improve mood, and promote mental health. Extensive research has been conducted both domestically and internationally on the relationship between strength training and blood pressure, but the conclusions are not yet consistent.

This inconsistency may stem from variations in the intensity, target body parts, and subjects of strength training, indicating a lack of standardized criteria. Recent studies have shown that, within a certain range, low- to moderate-intensity resistance training can produce effective blood pressure reduction without causing excessive increases in blood pressure. Authoritative sports medicine institutions still do not recommend strength training as the first-line exercise for hypertension; physical exercise must be conducted while ensuring safety.

However, as a form of exercise that can enhance muscle strength, improve physical fitness, and promote health, it should not be excluded from exercise prescriptions for hypertension. Instead, attention should be paid to intensity control to make strength training in hypertension exercise prescriptions safer and more effective. Diastolic blood pressure refers to the lowest blood pressure in the arteries when the heart relaxes. Diastolic blood pressure is the pressure generated by the elastic recoil of arteries. Normal diastolic blood pressure for adults is below 90 mmHg.

Diastolic blood pressure is affected by peripheral vascular resistance, heart rate, and arterial elasticity. Obese patients have significantly increased peripheral vascular resistance and a faster heart rate, resulting in higher diastolic blood pressure. In hypertensive patients, diastolic blood pressure decreases during exercise due to several factors, including decreased peripheral resistance. During exercise, vasodilation of the active muscles increases capillary density and number, improving blood circulation and metabolism, and reducing total peripheral resistance, thus helping to lower blood pressure, especially diastolic blood pressure.

Reducing blood volume. Exercise increases urinary sodium excretion, relatively reducing blood volume and thus lowering excessively high blood pressure. Exercise training can increase atrial natriuretic peptide levels and decrease insulin levels, thereby reducing blood volume and lowering plasma norepinephrine levels, thus regulating blood pressure. Endurance training and aerobic exercise reduce sympathetic nerve excitability, increase vagal nerve tone, relieve small artery spasms, and lower diastolic blood pressure.

Adaptive changes in the vasomotor center. Transient increases in blood pressure during exercise can affect the cerebral cortex and subcortical vasomotor centers, readjusting the body's blood pressure regulation level so that blood pressure can be balanced at a lower level after exercise. Long-term aerobic training can reduce the body's stress response, improve the patient's adaptability, and reduce stress responses that affect blood pressure elevation.

Long-term moderate-intensity aerobic exercise can cause adaptive structural changes in the heart, mainly manifested by ventricular enlargement. It can also cause a moderate increase in myocardial contractility, an increase in end-diastolic volume and a decrease in end-systolic volume of the ventricular cavity, an increase in stroke volume, a significant decrease in resting heart rate, a prolongation of ventricular diastole, and a decrease in diastolic blood pressure.