Blood pressure and how exercise can take the pressure down
The statistics
High blood pressure (or hypertension) is the most common of all the conditions of the circulatory system. (ABS – Australian Health Survey 2011/12)
In 2003, high blood pressure was the greatest attributor to the burden of cardiovascular disease (CVD) accounting for 42.1% of CVD’s total burden. (Australian Institute for Health and Welfare - The burden of disease and injury in Australia 2003)
In 2011/12, 4.6 million Australians (32%) aged 18 years and over had high blood pressure (systolic or diastolic blood pressure is ≥140/90 mmHg or taking medication).
Of these, more than two thirds (68%) had uncontrolled or unmanaged high blood pressure (not taking medication), representing 3.1 million adult Australians. (ABS – Australian Health Survey 2011/12)
In 2011/12, men were more likely to have uncontrolled or unmanaged high blood pressure than women (23.6% vs. 19.5% respectively), while the proportion of Australians with uncontrolled or unmanaged high blood pressure increased with age. (ABS – Australian Health Survey 2011/12)
What is hypertension (high blood pressure) and do you have it?
Blood pressure is the force exerted by the blood on the walls of the arteries and is written as systolic/diastolic (e.g. 120/80 mmHg, stated as '120 over 80').
The World Health Organization defines high blood pressure as including any of the following:
systolic blood pressure greater than or equal to 140 mmHg, or
diastolic blood pressure greater than or equal to 90 mmHg, or
receiving medication for high blood pressure.
How does hypertension effect your health?
High blood pressure puts stress on the artery walls and, over time, they may become damaged (thickened or weakened). Thickened artery walls reduce the blood flow through the heart which may lead to the heart working harder or blocking blood flow completely. If the artery is blocked, then some of the heart muscle or other organs may be depleted of oxygen.
Stroke
If an artery supplying the brain with blood becomes blocked or restricted, or is damaged by high blood pressure and bleeds, this results in failure of the blood supply to the affected part of the brain, resulting in brain damage. This is called a stroke.
Heart disease
If the heart muscle is depleted of oxygen for a period of time it may become damaged which restricts the heart’s capacity to pump blood around the body. Also known as a heart attack.
Kidney disease
If a kidney has a reduction in blood flow due to a blocked or damaged artery that kidney may be damaged and unable to remove waste and extra fluid from your body. Over time this leads to reduced kidney function.
How to manage hypertension?
There are two main ways you can manage hypertension; medication and lifestyle modification. Medication management is best discussed with your GP and lifestyle modification is encouraged before looking at medication. Some of the lifestyle modifications you can make include:
lose weight – being overweight increases fatty tissue which increases arteries blood flow resistance which increases the work placed on the heart (i.e. it has to work harder)
limit alcohol
reduce sodium (salt) intake in your diet – too much salt in your diet can cause the strain on the kidneys which results in extra fluid and strain on the blood vessels causing an increase in blood pressure.
increase aerobic exercise such as walking and cycling
How does exercise improve hypertension?
One of the ways that hypertension is reduced long term is the body’s adaptation to the exercise. When you exercise you are training the heart and lungs to get stronger and more efficient. You need to do the exercise regularly for the body to adapt to the exercise. The main way in which exercise can improve hypertension is with increased cardiac output and reduced resistance to blood flow.
Improved cardiac output is achieved mainly by:
Decreased heart rate and
Increased stroke volume (increased amount of blood pumped per heart beat)
If the arteries that carry the blood throughout the body provide less resistance (i.e. they are relaxed), the heart is pumping less frequently and more blood is pumped per beat, this means that the heart is not having to work as hard and hence the pressure is reduced.
References
Australian Bureau of Statistics. Australian Health Survey 2011/12 (4364.0) October 2012
Heart Foundation. HeartWatch Survey 2011.
Begg S, Vos T, Barker B, Stevenson C, Stanley L, Lopez AD, 2007. The burden of disease and injury in Australia 2003. PHE82. Canberra: AIHW.
Durstine, J. L. and Moore, G. E. 2002. Exercise management for persons with chronic diseases and disabilities.