Introduction
High blood pressure or hypertension is a major cause of premature death due to cardiovascular disorders among the aging population. Health experts often recommend lifestyle changes that include physical exercise as a first-line intervention to reduce high blood pressure, coupled with lowering the risk of adverse cardiovascular events. “Physical inactivity is a recognized major risk factor for cardiovascular disease, and persons who are less active and less fit have a 30 per cent to 50 per cent greater risk for high blood pressure” (Lellamo, &Volterrani, 2010, p.68). Healthcare professionals emphasize appropriate lifestyles as a way of assisting patients with hypertension to achieve lower blood pressure. Health experts recommend that hypertensive patients should perform exercises that include moderate aerobic activities and resistance training to improve both endurance and strength. However, since physical activity has a direct relationship with health outcomes, higher exercise levels confer greater health benefits to the patient. However, certain considerations are necessary to achieve higher health outcomes. In the hypertensive population, the recommended therapeutic lifestyle changes include weight loss, avoiding sedentary lifestyles, dietary changes, and most importantly regular physical activity. Therefore, this essay examines the cardiovascular benefits of exercise in the management of blood pressure among the hypertensive population.
Theoretical Rationale
Physical exercise triggers a series of physiological mechanisms that have a significant impact on the cardiovascular system. Since functions of the cardiovascular system depend on the conditions of the heart and blood vessels, exercise causes significant changes in the vascular system. Normal exercise increases the rate of heartbeat, thus increasing blood pressure. However, increased blood pressure during physical activity has no harmful effect on an individual when compared to increased blood pressure during rest. Ideally, the heart is adapted to pumping blood at a given pressure under normal circumstances and at another pressure during activity. Through adaptation, the heart has managed to regulate blood pressure according to prevailing conditions. “The mechanisms responsible for the adaptations of the cardiovascular system to exercise and the limitation indexes of the cardiovascular function are basic aspects related to the understanding of the adaptive functions” (Monteiro, & Filho, 2004, p. 517). Changes in the rate of heartbeat and blood pressure without any cause would mean that the vascular system has a problem. Often, hypertension emerges when both systolic and diastolic pressures increase above normal.
Exercise is important to the heart because it increases cardiac activity, thus promoting the heart’s physiological function, as well as muscular function. The heart uses a lot of energy to sustain its physiological functions. Given that it is a muscular organ, it has numerous mitochondria that generate the required energy. During resting, the heart pumps blood with low pressure using minimal energy; hence, the rate of heartbeat is low. In contrast, during an activity, the rate of heartbeat increases as it pumps blood at high pressure, thus increasing the flow of blood. Moreover, since the heart is a muscular organ, an increase in the rate of heartbeat implies that the heart is functioning optimally. In this view, exercise enables the heart to strengthen its muscles, which results in increased functioning. Baak (1998) asserts that exercise improves the condition of the heart muscles and reduces blood pressure among hypertensive patients. Therefore, exercise improves physiological processes of the heart and muscular functioning, which result in normal heartbeat and blood pressure during activity and rest.
Given that exercise promotes the pumping mechanism of the heart, it consequently improves the vascular system. Blood vessels in the vascular system have muscles that should be elastic as blood flows through them. The elasticity of the blood vessels does not only depend on the nature of the muscles that are in them but also the blood pressure. Variation in blood pressure during activity and rest provides essential exercise on the muscles because they can contract and relax optimally. Poor vasodilation and vasoconstriction of blood vessels have contributed to anomalies in blood pressure. Constricted blood vessels cause hypertension because they prevent the free flow of blood in the body. Moreover, blood vessels with poor elasticity of muscles increase peripheral resistance, thus increasing blood pressure. Physical exercise enhances the circulation of blood in the body by enhancing vasodilation, which consequently improves the muscles of the vascular system (Ciolac, 2012). Therefore, exercise is good for the optimal functioning of muscles that are important in the reduction of blood pressure in the vascular system.
Poor supply of oxygen in the body prompts the heart to increase the rate of heartbeat. Increased rate of heartbeat causes an increase in blood pressure, both in diastolic and systolic pressures. In this case, exercise promotes the circulation of oxygen in the body, thus preventing the occurrence of hypertension due to an increased rate of the heartbeat during resting. Increased demand for oxygen occurs when the body is unable to replenish the oxygen used in the body. According to Monteiro and Filho (2004), “physiological and metabolic processes optimize the oxygen distribution throughout tissues in activity,” (p.517). Optimization of the oxygen distribution relieves the heart from increasing the rate of heartbeat, as a means of satisfying increased demands for oxygen.
Scientific Evidence
Most healthcare professionals such as physiologists and nurses recognize regular exercise as central in the management of hypertension in patients by influencing positive behavior changes that help to achieve blood pressure control. The recommended physical exercises include aerobic (endurance) exercise and resistance (strength) exercise. A number of studies have demonstrated that aerobic exercises have the effect of postponing the onset of hypertension among predisposed groups. A prospective study established the impact of lack of exercise on the aerobic capacity of young men aged 26 years. The young men received three weeks of bed rest after which aerobic test showed, “Their aerobic capacity had declined significantly at the end of the three weeks bed rest” (Hedge, 2003, p.297). When the young men went through a six months period of moderate training, they regained their aerobic capacity. Hence, the study shows that exercise is important in enhancing the aerobic capacity of hypertensive patients.
Essentially, low blood pressure in hypertensive patients occurs after intensive aerobic training. Exercise has different physiological effects, which occur in stages, viz. “Immediate acute, late acute, and chronic” (Monteiro, & Filho, 2004, p. 517). The immediate acute effects involve an increase in cardiac frequency, sudoresis, and enhanced pulmonary ventilation. Comparatively, late acute effects happen within 72 hours after exercise, and the effects entail a reduction in blood pressure, vasodilation, improved endothelial function, and increased sensitivity of muscles to insulin. Ultimately, the chronic effects signify adaptations that one achieves after performing exercise for long. Hence, the chronic effects are long-term impacts such as increased aerobic capacity, muscular hypertrophy, and ventricular hypertrophy. A study done to find out the influence of exercise on hypertension showed that subjects who performed intensive exercise had better hypotensive effects than those who did moderate exercise (Ishikawa-Takata, Ohta, &Tanaka, 2003). Hence, from the evidence described above, it is clear that aerobic exercise is an important intervention in the prevention and management of hypertension among patients.
Furthermore, some evidence demonstrates that resistance (strength) exercise lowers the level of blood pressure in hypertensive patients. Ample evidence shows that moderate resistance training has a significant impact on the reduction of blood pressure. However, intensive resistance training does not correlate with the hypotensive effect; thus, it implies that moderate resistance training and intensive aerobic exercise are the forms of exercise that are critical in the prevention and management of hypertension. According to Gauer and O’Connor (1999), exercise causes “a reduction in cardiac output, peripheral vascular resistance and sympathetic nervous system activity” (p.19). The study further asserts that inactive individuals are at greater risk of developing hypertension than the general population.
Exercise has a hypotensive effect on the blood pressure of both the normotensive and hypertensive populations. Epidemiological studies conducted in the United States by Aerobics Center Longitudinal Study and Harvard Alumni Study indicated, “Normotensive individuals with a low level of physical activity or fitness have an increased risk of developing hypertension in future” (Baak, 1998, p.6). The epidemiological findings imply that physical inactivity predisposes individuals to hypertension, and thus links hypertension to exercise. Moreover, lack of exercise among hypertensive individuals worsens the condition of hypertension. Body of evidence indicates that exercise plays a central role in alleviating the impact of hypertension among hypertensive patients. Therefore, it suffices to conclude that exercise mediates the occurrence and progression of hypertension among hypertensive patients.
The Specific Exercises
An aerobic exercise is beneficial in the prevention and management of hypertension. The intensity and duration of the exercises determine the impact of exercise in enhancing cardiac functions and the elasticity of blood vessels. Hypertensive patients normally have high blood pressure during rest, which in turn influences their blood pressure during activity. According to Lellamo and Volterrani (2010), the aerobic activity of 30 to 60 minutes done 3 to 5 days a week has a significant impact on the heart by causing a heart rate of 55-85 per cent. The intensity of exercise determines the rate of heartbeat, which in turn influences blood pressure. An aerobic exercise of 30 to 60 minutes will result in enhanced cardiac capacity and vascular elasticity.
The intensity of exercise determines the impact of exercise in reducing blood pressure among hypertensive patients. Moderate intensity exercise that lasts for about 30 minutes has been a standard exercise recommended for the prevention and management of hypertension. The exercise is helpful in people who are unable to perform resistance exercise or intensive exercise. However, recent studies indicate that high-intensity training that involves intermittent rapid exercise has an enhanced impact than moderate-intensity exercise. “High-intensity training, which consists of several bouts of high-intensity exercise (~85% to 95% of HRmax) lasting 1 to 4 minutes interspersed with intervals of rest or active recovery, is superior to moderate-intensity training” (Lellamo, & Volterrani, 2010, p.102). The frequent activity of high-intensity exercise is central in the prevention and management of hypertension. Therefore, high intensity of exercise causes a concomitant decrease in blood pressure, which also implies that it has a significant impact in reducing predisposition to hypertension.
Exercise is also applicable in the management of obesity, which predisposes people to hypertension. Exercise enables people to reduce their weight and attain a normal body mass index so that they can prevent or manage hypertension. Scientifically, exercise enhances the metabolism of fats in the body and increases the oxidative capacity of muscles, which consequently leads to increased reduced peripheral vascular resistance. Lellamo and Volterrani (2010) assert that exercise increases vasodilation, which consequently results in a significant reduction in vascular resistance, thus causing reduced blood pressure. High intensity of exercise usually has a greater impact on body mass index because it increases the development of muscles and reduces adipose tissue. Consequently, reduced mass of adipose tissue improves the growth of muscles thus reducing peripheral vasoconstriction. Hence, exercise is relevant in reducing body mass index, as well as blood pressure among hypertensive patients.
Outcome Measures
Measurement of blood pressure is a good parameter for measuring the impact of exercise on hypertension. Since exercise reduces blood pressure among hypertensive patients, measuring the change in blood pressure provides a real impact of exercise. Hence, to measure the impact of exercise, monitoring both systolic and diastolic blood pressure is essential. The normal systolic pressure should be between 100 to 140 mmHg, while diastolic blood pressure should be in the range of 60 to 90 mmHg. Therefore, monitoring of blood pressure at rest is central in determining the influence of exercise on hypertension. Baak (1998) asserts that measurement of blood pressure before and after moderate intensive training is appropriate for determining the extent to which exercise influences blood pressure. Moderate intensive exercise is suitable because it has no adverse effects on hypertensive patients.
Body mass index is another outcome that measures the effect of exercise on the body of a hypertensive patient. As obesity predisposes people to hypertension, measurement of body mass index shows how exercise influences hypertension. The nature and intensity of exercise correlate with the amount of bodyweight that an individual loses. Hence, measurement of body mass index before and after physical exercise should indicate that there is a significant reduction in body weight. Gauer and O’Connor (1999) argue, “if one expends 500 to 1,000 kilocalories per week for 52 weeks, approximately 7 to 15 pounds could be lost each year” (p.75). Loss of about 500 kilocalories per week causes a significant reduction of body weight in the end, hence a useful parameter in the measurement of the effect of exercise among hypertensive patients.
Since the amount of oxygen that tissues need influences the rate of heartbeat and blood pressure, measurement of aerobic capacity indicates the influence of exercise on hypertension. Ideally, aerobic capacity indicates the amount of oxygen that blood can transport to tissues and cells during optimal exercise. Low aerobic capacity implies that one is prone to hypertension, while high aerobic capacity reduces the risk of hypertension. Gauer and O’Connor (1999) posit, “The optimal intensity for aerobic exercise training occurs at 50 per cent to 85 per cent of the functional aerobic capacity (VO2max)” (p.60). Therefore, measurement and monitoring of aerobic capacity are central in the prognosis of hypertension among patients.
Conclusion
Hypertension is a cardiovascular disorder that leads to increased blood pressure in the body. Medical experts attribute hypertension to lifestyle changes that have made people live sedentary lifestyles. As lack of exercise predisposes people to hypertension, medical experts and the World Health Organization recommend that exercise is the best intervention in the prevention and management of hypertension. Daily moderate intensive exercise and highly intensive exercise have proved as effective measures in the prevention and management of hypertension among patients. Measurements of systolic blood pressure, diastolic blood pressure, body mass index, and aerobic capacity are good parameters that measure outcomes of exercise in the prevention and management of hypertension.
References
Baak, M. (1998). Exercise and hypertension: facts and uncertainties. British Journal of Sports Medicine, 32, 6-10.
Ciolac, E. (2012). High-intensity interval training and hypertension: maximizing the benefits of exercise. American Journal of Cardiovascular Diseases, 2(2), 102-110.
Gauer, R., & O’Connor, F. (1999). How to write exercise prescription. Web.
Hedge, B. (2003). Health Benefits of Exercise. Journal of Association of Physicians of India, 51, 297-298.
Ishikawa-Takata, K., Ohta, T., & Tanaka, H. (2003). How much exercise is required to reduce blood pressure in essential hypertensives? A dose-response study. American Journal of Hypertension, 16(8), 629-633.
Lellamo, F., & Volterrani, M. (2010). Effect of exercise training in essential arterial hypertension. Rev Bras Hipertens, 17(2), 68-71.
Monteiro, M., & Filho, D. (2004). Physical exercise and blood pressure control. Rev Bras Med Esporte, 10(6), 517-519.