Blood pressure and the different classifications
Blood pressure is a measure of the force that blood applies to the walls of the arteries as it flows through them, it is measured in millimetres of mercury (mmHg) & is expressed using two numerical readings. The two numerical readings represent the systolic & diastolic blood pressures.
Systolic blood pressure (SBP) is the pressure exerted on the artery walls when the cardiac muscle is contracting (systole) & pumping blood. This is the higher of the two numbers & is usually noted first. It is caused by the rise in volume of blood flowing through the arteries with each beat, which increases the pressure within the arteries.
Diastolic blood pressure (DBP) is the pressure exerted on the artery walls when the heart is in a relaxed state. The heart goes through this period of relaxation (diastole) to allow the chambers to fill with blood prior to contraction. The diastolic blood pressure is always the lower of the two readings.
All blood vessels are able to widen known as vasodilation or narrow known vasoconstriction. This is because of the smooth muscle found in their walls, it is this change in vascular tone which enables the body to direct the flow of blood to different tissues and plays a part in the regulation of blood pressure. An example of this occurring is after eating a meal, where the blood vessels that feed the digestive system become vasodilated & blood flow is increased to assist digestion, while blood vessels feeding the muscles are vasoconstricted, reducing local blood flow.
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The circulatory is a closed system in which the pressure varies constantly throughout the day, having a blood pressure in optimal ranges significant reduces the rick of cardiovascular disease which many individuals do not know they have until they have there blood pressure checks. This is how hypertension is termed the silent killer as many people with high blood pressure don’t even know they have it.
Normal blood ranges fall between 100-130 systolic and 60-85 diastolic, with readings lower than may possibly have clinical significance but are not associated with increased CVD risk and is termed hypotensive, individuals may wish to see a GP to find the cause. Having an optimal blood pressure reduces the risk of cardiovascular disease (CVD), optimal blood pressure is below 120mmHg for systolic & 80mmHg for diastolic pressure, individuals are safe to exercise with no concern.
Readings above optimal level do pose an increased cardiovascular risk with readings above 140mmHg systolic & 90mmHg diastolic being classed as stage 1 hypertensive where individuals require check-up from their GP and must be either referred or cleared to exercise ahead of any intervention.
Individuals with blood pressure above 160/100 are classed as Stage 2 hypertensives and a high risk individual who will need to exercise under specialist instructor supervision, with individuals over 180/100 being classified as stage 3 hypertensives being totally contraindicated for exercise due to their high risk of an acute CV event. Exercise for theses individuals will be completed in a clinical environment with medically supervised professionals.