Hypertension, more commonly referred to as high blood pressure, is a condition diagnosed when an individual has abnormally high blood pressure. Blood pressure refers to the pressure placed against the walls of the large arteries when the left ventricle, or pumping chamber of the heart, is contracting (systole) and relaxing (diastole). Hence, the two numbers we see when measuring blood pressure refers to exactly this. The top number which is always higher, represents systolic blood pressure, or the pressure placed on the major arterial walls when the heart contracts. Conversely, the bottom, or lower number, represents diastolic blood pressure, or the pressure placed on major arterial walls during relaxation. A ‘normal’ BP reading is considered to be 120/80, and these values represent an estimation of the pressure that the organs are exposed to.
Hypertension is diagnosed when blood pressure readings are in excess of 140/90 following multiple readings. Hypertension is often categorized into 3 stages:
Hypertension is the most common cardiovascular disease and it is associated with an increased incidence of all-cause and cardiovascular disease mortality. Furthermore, excessively high BP is a major risk factor for chronic kidney disease, heart failure, cardiovascular events and early death. Hypertension may not cause symptoms, which is why it is often referred to as a ‘silent killer.’ Furthermore, as we age, our arteries harden and become less elastic. This has a significant impact on increasing blood pressure as the pressure placed against arterial walls when the heart contracts and relaxes is far greater when the walls are stiffer.
The Effect of Exercise on Hypertension:
In order to prevent, treat and manage hypertension, lifestyle modifications are advocated, with exercise as an integral component. Exercise remains the cornerstone therapy for the prevention and control of high blood pressure. Exercise programs that involve both aerobic and resistance training prevent the development of hypertension and lower blood pressure in adults. Mechanisms that explain the BP lowering effects of exercise include:
- Neurohumoral, vascular and structural adaptations. The heart and vascular system are partly regulated by neural (autonomic) and humoral (circulating or hormonal) factors. Alterations in the regulation of the sympathetic nervous system as well as structural adaptations in the elasticity of arterial walls play a role in reducing blood pressure.
- Decreases in catecholamines and total peripheral resistance. Reductions in catecholamines (such as adrenaline) will stem from neurohumoral adaptations discussed above, while a reduction in these will play a role in lowering BP. Peripheral resistance essentially refers to the resistance of blood flow; a lower resistance will correlate with a lower BP as less force is exerted against arterial walls.
- Improved insulin sensitivity – Insulin resistance and hypertension often coexist, as 50% of hypertensive individuals display glucose intolerance, while up to 80% of type 2 diabetics have hypertension. Insulin induces vasorelaxation (relaxation of the arteries and reduction in tension), while it regulates sodium (salt) homeostasis by increasing sodium reabsorption in the kidney, therefore contributing to a reduction in blood pressure.
- Alterations in vasodilators and vasoconstrictors – Vasodilation refers to the dilation of blood vessels, which has a lowering effect on BP as the force exerted on vascular walls is reduced. Alternatively, vasoconstrictors increase BP by constricting blood vessels, thereby increased the pressure placed against walls during systole and diastole. Hence, alterations in these mechanisms can have a lowering effect on blood pressure.
How much/what type of Exercise should I be completing?
The American college of Sport and Medicine (ACSM) recommends, based upon current evidence, that the following exercise prescription be followed for those with hypertension:
- Frequency: On most, preferably all days of the week
- Intensity: Moderate intensity
- Time: At least 30mins of continuous or accumulated physical activity per day
- Type: Primarily endurance physical activity supplemented by resistance exercise
Aerobic exercise will help to lower BP by making your heart stronger, as well as the benefits discussed above. The research surrounding benefits of strength and resistance training is not as thorough in comparison to aerobic exercise; however it certainly does not have a negative effect on managing blood pressure. When completing resistance training, be sure to continue breathing out during ‘push phases,’ as holding your breath can cause spikes in blood pressure. Isometric contractions (i.e. holding a weight in a static position for extended periods), as well as overhead lifts, are also not recommended for similar reasons. Resistance training will help improve muscular strength and mass which will help you burn more calories throughout the day. It is also good for your joints and bones and will help with completion of activities of daily living, while it is linked with a reduced risk of falls or development of other chronic diseases. Such increases in metabolism at rest will help manage blood pressure by aiding in weight loss and in reducing obesity. Obesity is considered a major risk factor for hypertension as it is linked with an increased HR and a reduction in the body’s ability to transport blood through blood vessels, while the formation of blood clots can also occur. These are all associated with an increase in the pressure placed on vascular walls thereby increasing blood pressure. Hence, completing a mix of both forms of training will have positive effects on managing your high blood pressure and health!
Our initial consultation process, as well as all subsequent reviews at Inspire Fitness for Wellbeing will involve measurement and tracking of your blood pressure. If you are someone with high blood pressure, I hope this article has educated you on the potential benefits that a mix of aerobic and resistance training can have for the management and treatment of hypertension.
If you are seeking guidance to commence exercise and reap the benefits discussed throughout this article, please contact us on 9857 3007 so we can begin designing you your own individualized training program to get you started!