10 blood pressure myths

In this article we will describe 10 blood pressure myths. Let’s start with the basics.

Key Points

• Myth: Normal blood pressure is 130/80 (there is no normal value)
• Myth: You can ‘feel’ your BP (you cannot 99% of time; it’s a silent problem)
• Myth: BP goes up in pregnancy (it goes down)
• Myth: When BP is better, I can stop treatment (no, its a long term treatment)
• Myth: My doctor should monitor my BP (you should)

1. Myth: Normal blood pressure is 130/80 Hg

Fact: Blood pressure is not a disease and there is no such thing as ‘normal blood pressure’. But for most adults, it will be between 110/70 and 140/90 most of the time. So, yes, 130/80 is a good average target for most patients, but is not ‘normal’.

Blood pressure is what doctors call a ‘biomedical variable’, i.e. a feature of you (and not a disease). And you would not treat someone for being 5 foot 10 inches tall.

But, it is a little more complicated than that, as there are some other things that affect it. For example, BP rises naturally as you get older. So 120/70, 130/80 and 140/90 are considered ‘normal’, if you are under 30 years (or pregnant), 30-70 years and 70 years.

The top and bottom numbers both matter – if either of them is persistently high, then you may have hypertension. Why does high BP matter? It is because it is a risk factor for stroke and heart attack, and increases their likelihood a little. That does not mean it causes them.

2. Myth: The signs of high blood pressure are obvious

Fact: High blood pressure has no symptoms. For most people, high blood pressure (BP) is ‘silent’, i.e. you cannot ‘feel’ whether it is high or low.

90% of people have mild-moderate high blood pressure (hypertension) without complications. The BP may be 140/90 to 165/95. Doctors call this ‘essential or primary (i.e. no underlying cause) hypertension’.

10% have a more serious type, called secondary hypertension, where the BP may be higher than this level. Secondary means there is an underlying a cause (like chronic kidney disease, CKD) or effect (damage to the heart).

There are no symptoms of high BP in either type.

3. Myth: Treatment of high blood pressure stops heart attacks, strokes, and will make me live longer

Fact. Treatment of mild-moderate essential BP in many people will reduce the likelihood of stroke (and probably heart attack) a little – but not absolutely prevent it.

However many people with heart attack or stroke have normal BP. And there is no evidence that treatment of essential or secondary high BP will make you live longer. But treatment of secondary high BP in CKD can slow the rate of decline of kidney function.

There is a small number of people with a really serious form of high BP called an ‘hypertensive emergency’. It used to be called malignant or accelerated hypertension. Then the BP is very, very high (e.g. over 190/110) and you are unwell (as it can lead to blindness, heart or kidney failure). If you have this type, you will need admission to hospital to get it under control. This type is especially common in Black people.

4. Myth: Blood pressure is constant

Fact: It goes up and down all day long.

And it varies from minute to minute. So it could be 142/97 now (a little ‘high’) and 118/73 ( a little ‘low’) two minutes later. This is why it is important not to over-interpret a single measurement.

5. Myth: High blood pressure is more common in men

Fact: It depends on age.

Before the age of 50 years, hypertension is more common in men than women. But after the menopause, a woman’s risk increases and can even be higher than a mans.

6. Myth: High blood pressure is common in pregnancy

Fact: Blood pressure normally goes down, in the early stage of pregnancy (first trimester, i.e. three months).

So, it is not common in pregnancy. Indeed, if BP is 140/90 in pregnancy, this can be quite serious – and require action by your midwife. They may need to get a hospital consultant to see you.

Women have a few additional considerations for high blood pressure. Taking the oral contraceptive pill can cause hypertension (i.e. is a secondary cause). Also women with high BP have a greater risk of complications during pregnancy; and women who develop high BP during pregnancy, are more at risk of having high blood pressure later in life.

7. Myth: The risk of high blood pressure is the same for people of all races

Fact: Black and Asian adults have an increased risk of developing high blood pressure.

Although the reasons why are not completely clear, hypertension is more common amongst Black adults than other ethnic groups.

Also, in Black and Asian people, high BP may (1) develop at a younger age, and (2) and be more severe (and therefore more likely to cause admission to hospital). Doctors think this may be partly because obesity and diabetes are more common. But there may also be genetic and socioeconomic factors.

8. Myth: There’s nothing I can do to prevent high blood pressure, if it runs in my family

Fact: Lifestyle changes can reduce your risk.

High BP can run in families – if your parents or close blood relatives have had high blood pressure, you are more likely to develop it too. However, lifestyle choices allow many people with a family history of high BP to avoid it themselves.

In addition to following a healthy low-salt diet, maintaining a healthy weight and regular exercise can have an impact on reducing blood pressure. Chronically high levels of stress and inadequate sleep can also contribute to high BP. So managing stress and ensuring you get adequate sleep, can help as well.

9. Myth: If I’m on blood pressure medication, I do not have to exercise or watch what I eat

Fact: You still need to continue a healthy lifestyle.

There is no substitute for trying to adhere to a healthy diet and exercise. When your doctor starts you on blood pressure medication, it is only because they believe these lifestyle measures are not enough to lower your BP to normal. They may try three months of healthy lifestyle advice to see what effect that has, before startng treatment.

But if they do start treatment, that does not mean you should stop focussing on a healthy lifestyle.

Reducing alcohol consumption can also have a positive impact on your blood pressure. Limiting alcohol consumption to no more than 14 units a week (i.e. about 2 drinks per day) can help reduce your BP.

9. Myth: If my blood pressure comes down on medication, I can stop taking it

Fact: You should continue taking it.

High blood pressure is a lifelong condition. Medication does not cure hypertension. If you stop taking your medication, then your BP will rise again.

If you have any questions or concerns about your medication or treatment plan for high blood pressure, talk to your GP, or practice nurse.

10. Myth: My doctor monitors my blood pressure

Fact: No, you should  monitor it – and show the results to your doctor.

Summary

We have described 10 blood pressure myths. We hope you understand it better now.

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