Around one in four South Africans has high blood pressure (although only half of them know it) – a major risk factor for heart attacks and strokes. Do you know the key causes?
There’s no way of telling from the outside if you have high blood pressure. You can feel perfectly well and yet the force of blood pressing against the walls of your arteries can be high enough to be slowly causing damage that increases your risk of heart disease, strokes and kidney failure.
But there are some known key factors that increase your risk:
- Age – Sixty per cent of people aged 60 or more have high blood pressure. Our arteries stiffen with age. This means the same volume of blood is forced into a smaller area and so your blood pressure may rise, sometimes dramatically.
To imagine the strain this puts on your heart, think of the pressure you need when you blow up a round balloon compared to how much you need to blow up one of those long skinny balloons used to make balloon animals.
- Family history – Have one or both of your parents had high blood pressure? Family history contributes anywhere between 2 and 10 per cent of your risk of developing high blood pressure, depending on your age and whether one or both parents had a blood pressure problem.
- Smoking – This adds to the risk of developing high blood pressure and older people are more vulnerable. Smoking markedly increases the risk of heart disease or stroke for a given level of high blood pressure compared to a non-smoker.
- Excess alcohol – Regular alcohol intake is clearly associated with high blood pressure. It seems to have an especially marked effect on the blood pressure of older women who smoke. For them, two standard drinks, can elevate blood pressure. Regular heavy or binge drinking, however can cause substantial rises in blood pressure, sometimes extreme enough to lead to a stroke. Alcohol can also impact on the effectiveness of blood pressure lowering medication.
- Being overweight or obese – Obesity increases the risk of developing high blood pressure in the next four years by 6 per cent. Extra body fat around your middle carries the greatest risk.
- Low physical activity – People who spend a lot of time watching TV and little time on physical activity have been shown to have higher blood pressure than more active people.
- Kidney disease – Inflammation and infection (among other things) can cause kidney disease, which is a major cause of high blood pressure. And once you have high blood pressure, it can make kidney disease worse. Someone with normal kidney function who is in the early stages of high blood pressure is likely to develop kidney disease in the next six years if they don’t receive blood pressure treatment.
- Diabetes – High blood pressure is much more common in people with diabetes (60 per cent of people with type 2 diabetes and 40 per cent of people with type 1 have high blood pressure.
- Excess salt in the diet – Sodium chloride (salt) is the main source of sodium in most foods. As sodium in our blood increases, the blood vessels retain water to try to balance the sodium concentration. This extra water increases the volume of blood in vessels, causing high blood pressure.
The recommended maximum salt intake is less than 6 grams a day but most of us eat more than this. Some takeaway pizzas contain 13 grams per single pizza! Bread alone contributes 20 per cent of dietary salt intake and processed meats 15 per cent. Condiments, sauces and marinades we add to food are often very high in salt.
- Rare causes – About 5 per cent of people with high blood pressure have a specific underlying cause, generally related to their kidneys, their aorta (the major artery which takes blood away from the heart) or hormonal conditions. Unlike the most common forms of high blood pressure, which generally require lifelong treatment, many of these rare causes of high blood pressure are curable.