Demystifying blood pressure

cardiac rehabilitation, blood pressure, living well

We take your blood pressure before and after every CP+R session, but what is blood pressure and why is it so important?

What do the numbers mean?

A blood pressure reading is broken down into two parts:  “systolic” (the upper number) and “diastolic” (the lower number).

Systolic blood pressure is the pressure exerted on vessel walls when your heart contracts (or “beats”) and forces blood out of the arteries. This is the highest your blood pressure will be. Diastolic blood pressure is the pressure exerted when the heart relaxes and fills with blood.

The normal ranges for systolic and diastolic blood pressure are 100 – 140mmHg and 60 – 90mmHg respectively, with optimal ranges classified as less than 120mmHg and less than 80mmHg. 120/80mmHg is commonly referred to as the “textbook value”.

N.B. Blood pressure readings are unique to the individual, and therefore to have a lower blood pressure outside of these ranges can be normal for some people.

Why do we take blood pressure at CP+R?

We need a certain amount of pressure in our arteries to ensure blood flow is maintained. However, if blood pressure is too high it can indicate too great a workload on the heart. Over time, this can sometimes cause complications that in turn lead to a stroke, heart attack or kidney disease.

Checking your blood pressure at CP+R allows us to confirm your blood pressure is in a healthy range relative to you. We can then adapt your session as needed to ensure it is safe and your heart is working under an appropriate load.

How can blood pressure change throughout the day?

It is normal for your blood pressure to fluctuate throughout the day as it is affected by a number of variables. For example, it rises if you become stressed, nervous or excited, or when you eat and drink, and it lowers when you sit and lie down. Blood pressure is also affected by the time, often reading higher in the mornings and lower in the evenings and during the night.

How can exercise improve your blood pressure?          

Exercise can improve blood pressure acutely (i.e. a reduction between the start and end of your one hour session at CP+R) and chronically (i.e. a long-term reduction over a number of programmes at CP+R).

This occurs for the following physiological reasons:

+ Acute reduction

When you begin exercising in your session, there will be an initial rise in blood pressure in linear correlation to the increase in physical work. However, this then triggers physiological mechanisms to encourage vasodilation (the opening of blood vessels) thus reducing your blood pressure. Think of it like a busy motorway temporarily opening the hard shoulder to allow the traffic to flow more freely and thus reducing the “pressure”. 

+ Chronic reduction

Over time, exercise has been shown to improve the function and increase the number of small arteries, arterioles and capillaries: key component vessels in blood pressure regulation. This facilitates control of the vasodilation/vasoconstriction response and a greater capacity for blood flow. Indeed, the more vascular beds you have, the more efficiently you are able to “distribute” blood pressure. Thinking back to the motorway analogy, imagine permanently building an extra road to better distribute the traffic and reduce the “pressure”.