What causes high blood pressure?
Usually no single thing. Salt, weight, alcohol, age and your genes add up over years. But for some people, a medicine or another condition is behind it. Treat that, and it may come back down.
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What causes high blood pressure?
Usually no single thing. The BHF says that in most cases there’s no specific reason. Instead, a few things add up and raise your chances.
Picture a bath filling from several taps. Salt, extra weight, alcohol and smoking are taps you can turn down. Age, genes and background are taps you can’t.
The more taps run, the more likely the bath overflows. You can’t shut them all. But the NHS says healthy changes can help lower your blood pressure.
| Cause | Can you change it? | What the evidence says |
|---|---|---|
| Too much salt | Yes | One of the main causes, says Blood Pressure UK. |
| Too much alcohol | Yes | Linked to a fifth of cases. |
| Being overweight | Yes | Strongly linked to high blood pressure. |
| Smoking | Yes | On the NHS list of things that raise your chances. |
| Little exercise, little fruit and veg | Yes | Both raise the risk, says Blood Pressure UK. |
| Stress over a long time | Partly | On the NHS list. Blood Pressure UK says there’s no evidence it causes long-term high blood pressure. |
| Getting older | No | Up to 5% of 16 to 24 year olds in England have it. At 65 to 74, 58% do. |
| Family and background | No | Higher with close relatives who have it, or a Black African, Black Caribbean or South Asian background. |
Sources: NHS; Blood Pressure UK
Up to 65, men tend to have higher blood pressure than women. From 65 to 74, women typically have higher.
Circle the yes rows that fit you. That’s where to start.
Could another condition be causing it?
Sometimes, yes. For some people a doctor finds one cause behind it. That’s called secondary high blood pressure.
The BHF gives these examples: kidney disease, diabetes, sleep apnoea and some medicines. Blood Pressure UK adds changes in blood supply to the kidneys, and hormone problems such as an underactive thyroid.
Blood Pressure UK says treating the cause could mean your blood pressure returns to normal.
Sleep apnoea is when your breathing stops and starts while you sleep. Without treatment, it can lead to high blood pressure. Signs include loud snoring and gasping in the night.
Ask your GP whether any of these could apply to you. More on sleep apnoea, kidney tests and an underactive thyroid.
Can medicines raise blood pressure?
Yes, some can. So can some over-the-counter and herbal remedies.
| Medicine or drug | What to know |
|---|---|
| Combined contraceptive pill | Contains the hormone oestrogen. The NHS says it may not suit you if you’ve had high blood pressure. |
| Steroids | Prescribed for many conditions. Ask your prescriber before any change. |
| Anti-inflammatory painkillers (NSAIDs) | Such as ibuprofen. Ask a pharmacist which painkiller suits you. |
| Some antidepressants | Ask your prescriber before any change. |
| Cough, cold and herbal remedies | Taking pseudoephedrine, a decongestant? Tell your pharmacist you have high blood pressure. |
| Recreational drugs | Including cocaine and amphetamines. |
Sources: Blood Pressure UK; NHS: combined pill; NHS: pseudoephedrine
Blood Pressure UK says your blood pressure might return to normal when you stop these. Never stop or change a prescribed medicine without your prescriber.
Worried about something you take? The BHF says to ask your doctor or pharmacist. Bring the boxes, including any remedies you bought yourself.
What causes sudden high blood pressure?
Stress is one. Stressful moments can make your blood pressure rise for a short time.
A stress spike rises, then falls
- 1
Stress hits
Your body releases the hormones adrenaline and cortisol.
- 2
Body reacts
Your heart beats faster and your blood vessels narrow.
- 3
Reading rises
Your blood pressure goes up for a short time.
- 4
Back to usual
Once the stress is over, it returns to its usual level.
Source: Blood Pressure UK
Nervous at the surgery? That can push a reading up too. See white coat hypertension and stress and blood pressure.
Pregnant? Around 1 in 10 women get high blood pressure in pregnancy. It’s often caused by pre-eclampsia.
Pre-eclampsia is most likely from 20 weeks, but can happen at any point. Sometimes it starts in the days or weeks after birth. The signs are in the GP section below.
One high reading? The NHS may ask you to use a home monitor for a few days. See how to measure at home.
Which causes can I change?
Most of the yes rows. The NHS says lowering your blood pressure even a small amount can help cut your risk of heart attacks and strokes.
Six NHS changes that target the causes you control
- Avoid salty food and adding salt to your meals.
- Lose weight if you’re overweight.
- Avoid drinking more than 14 units of alcohol a week on a regular basis.
- Aim for at least 150 minutes of exercise a week.
- Don’t drink too much caffeine, such as coffee, tea and cola.
- Don’t smoke.
Source: NHS: high blood pressure
Thinking of a potassium salt swap? NICE says these shouldn’t be used by older people, pregnant women, or people with diabetes or kidney disease.
The same goes if you take some blood pressure tablets, such as ACE inhibitors or ARBs. See salt substitute safety.
Start with one change this week. For which workouts help most, see exercise and blood pressure.
When to speak to a GP
High blood pressure does not usually cause symptoms. The only way to know is to get it checked. Speak to a GP if:
- Your reading is 140/90 or more at a pharmacy or surgery, or 135/85 or more at home. That usually counts as high.
- You’re 40 or over and haven’t had it checked for more than 5 years.
- You’re under 40 with high blood pressure. NICE says to consider a specialist check for a cause.
- Your breathing stops and starts in your sleep, you gasp or choke in your sleep, or you always feel very tired in the day. These can be signs of sleep apnoea.
- Your clinic reading is 180/120 or more. NICE advises checks for organ damage as soon as possible. It advises a same-day specialist check if you also have new confusion or chest pain. The same goes for signs of heart failure or sudden kidney damage, or bleeding or swelling at the back of the eye.
Pregnant or had a baby in the last few weeks? Get urgent help for signs of pre-eclampsia. These are a severe headache that simple painkillers don’t ease, blurred vision or flashing lights, or pain below the ribs.
Other signs are sudden swelling of the face, hands or feet, feeling very unwell, heartburn that heartburn medicines don’t ease, or being sick. If pregnant, call your maternity unit. If you’ve given birth or can’t reach them, call 111.
Get help from NHS 111 if you often have headaches or blurred vision, or chest pain that comes and goes. Also get help for other symptoms you’re worried could be from high blood pressure.
Call 999 for sudden chest pain or discomfort that doesn’t go away, such as squeezing, pressure, burning or indigestion. Also call for pain spreading to either arm, your neck, jaw, stomach or back.
Call 999 too for chest pain with sweating, feeling sick, light-headed or short of breath. Do not drive yourself to A&E.
To read your numbers, see blood pressure readings explained.