Before we begin, I just wanted to pop these stats in front of you….
· 34% of Australians (over 18) are have high bloodpressure (BP) – that’s about 6 million people
· 4.1 million Australians have uncontrolled or untreated hypertension
So, let’s answer a few commonly heard questions around iNform: 1)How does a bout of exercise affect my BP? A single episode of exercise is able to reduce BP post exercise. The magnitude (−2 to −12) and duration (4 to 16 hours) vary considerably between individuals as the environment, exercise prescribed, duration of exercise and genetic components can all affect change.
Let’s get scientific for a second: Systolic BP (the first number) refers to how much pressure goes through the arteries as the heart is contracting. We would love it to be around 120. Diastolic BP (the second and typically smaller number) refers to the arterial pressure during the relaxation phase of the heartbeat. The recommended value is approximately 80.
When we begin exercising our systolic BP increases because we need to pump more blood around the body to deliver oxygen and get rid of waste products. Our heart rate increases and the overall amount of blood moving through the arteries increases. Therefore the pressure the blood creates on the arteries also increases. However BP does not usually fly off the charts because our arteries dilate to allow the extra blood through and as such the resistance (and the pressure) decreases. Think of it like opening doors wider to allow more people to shop during the post-Christmas sales. So we would tend to expect a gradual increase in systolic BP until we hit a plateau at our exercise peak. Interestingly our diastolic does not often change much except in static exercises like wall sits.
How does it work? This happens through a variety of ways including increased hormonal activity, decrease in heart rate and nerve activity (sympathetic – due to decrease in circulating catecholamines).
However, given the many factors in our body that help regulate our BP, it is still proving difficult to identify a single mechanism for this drop. What is important though is the beneficial effects on the body!
2)Can regular exercise help me control my high BP The big new is yes! Regular physical exercise has been recommended for the prevention and treatment of hypertension. We have had a range of clients who begin to exercise regularly, decrease their BP and thus the decrease or even cease the medication they are on (based on GP’s clinical decision).
3) What exercise is best for individuals with high BP? Decrements in BP have been widely found in a majority of aerobic exercise including walking, running, cycling. Resistance training is a little more controversial is it tends to exhibit greater BPs during the exercise, however it does exhibit post exercise BP decrements. Each training mode produces different effects on the body so it highly encouraged to completing both modes.
4) How long should I exercise for? The acute decrease in BP has been observed after as little as 10 minutes and as long as 170 min of exercise, although the majority of studies have used exercise lasting between 20 and 60 min. So if time is a factor, you still gain benefits from a short bout of exercise.
To make long term changes, research shows that there seems to be a positive association to 3-5 days of exercise for approximately 30-60mins at greater than 65% intensity levels. However, just remember any type and duration will have a positive response when compared with no exercise.
5) What is the best way to work out my BP repose to exercise? Here at iNform, if we feel it is required we measure BP pre and post (sometimes during). This happens over a course of sessions and allows us to monitor the responses to the exercise prescription. It also allows us to change intensity, duration and mode to see how these effect individuals. We find different individuals respond better to different modes so we take an individual approach to determining it.
6)What risks are there of exercising with high BP? Both aerobic or resistance training can increase systolic BP, so ensuring that this rise does not exceed approximately is important. If systolic BP rises greater than 250 mmHg and/or diastolic BP >115 mmHg during exercise, the training session should be terminated.
Ways to decrease risk: a) Ensuring steady breathing during exercise is important to decrease build-up of pressure in arteries. This is especially evident in resistance training b) Completing dynamic movements rather than static exercises (such as wall sits) are important to decrease risk of excessive BP c) Upper body exercises tend to lead to an increase BP when compared to lower body exercise, however this is not saying no upper body exercise (just be mindful). d) Ensuring a progressive build-up of intensity during warm up and slow down when cooling down to reduce risk of sudden drops or increases.