What is blood pressure?
Blood pressure describes the force exerted on the blood vessels by the blood, as the heart contracts and relaxes. Blood pressure is measured with a sphygmomanometer, also known as a blood pressure monitor. Measurements are recorded in millimeters of mercury (mmHg). The recorded data is often displayed as a fraction, for example 120/80. The top or first value represents the systolic pressure, or the maximum pressure exerted on the blood vessels as the heart contracts. The bottom value represents the diastolic pressure, or the maximum pressure exerted on blood vessels by the blood as the heart relaxes.
What happens during exercise?
As exercise intensity increases, the cardiac output, or the amount of blood the heart pumps out per minute increases. Blood vessels to the gut and kidneys constrict, whilst blood vessels to the brain, heart, lungs and muscles dilate to deliver more blood and oxygen to fuel their processes. This increase in heart rate and vasodilation is regulated by the sympathetic nervous system (fight or flight system) through the release of hormones such as epinephrine, norepinephrine, nitric oxide and prostaglandins that target and dilate the blood vessels. During exercise, systolic blood pressure can increase above 160mmHg in intense exercise.
What happens after exercise?
After exercise, epinephrine and norepinephrine decrease, reducing heart rate and cardiac output, but there is a maintained increase in nitric oxide and prostaglandins that continue to dilate and relax blood vessels. Dilated blood vessels create less resistance as it’s easier for blood to pass through and blood pressure is decreased. It is important to note that this decrease in blood pressure may only be temporary. Adopting a consistent fitness regimen that combines cardio or any activity that increases heart rate helps to maintain the benefits of exercise.
