Blood pressure and kidney function
High blood pressure usually has no symptoms, and early kidney disease is silent too. This page explains how blood pressure is measured correctly, how the two are linked, and which tests are needed.
What is blood pressure?
Blood pressure is written as two numbers. The first is the highest pressure as the heart pumps, and the second is the lowest as the heart relaxes.
You are usually considered to have high blood pressure at:
- 140/90 or higher when measured at an office or clinic
- 135/85 or higher when measured at home
One high reading is not enough for a diagnosis. You may be asked to measure at home for a few days, to come back after some days or weeks, or to wear a monitor for 24 hours. How to measure is explained in the patient guide.
Why does it matter?
High blood pressure strains the blood vessels, heart, brain, kidneys and eyes. Untreated, it raises the risk of heart attack, stroke, heart failure, kidney disease and vascular dementia. Lowering it even a little reduces this risk.
Older age, family history, a salty diet, being overweight, smoking, alcohol and long-term stress all make it more likely.
What helps?
- Eating less salt
- A healthy diet, and losing weight if you are overweight
- At least 150 minutes of exercise a week
- Stopping smoking, and not having too much alcohol or caffeine
If your pressure is very high, your risk of complications is high, or these changes do not lower it, your doctor prescribes medicine. Sometimes more than one medicine is needed. The choice depends on your pressure, your age and your situation.
How are pressure and sugar linked to the kidneys?
Chronic kidney disease means the kidneys do not work as well as they should. High blood pressure strains the small vessels in the kidneys, and high sugar damages the kidneys’ filters. High cholesterol, kidney infection, kidney inflammation, blocked urine flow and long-term use of some medicines can also be causes.
There are usually no symptoms in the early stages, and the disease is often found in a blood or urine test done for another reason. At a more advanced stage you may see:
- Tiredness
- Swollen ankles, feet or hands
- Breathlessness
- Feeling sick
- Blood in the urine
Which tests?
Creatinine and urea in the blood, and a urine test, show how the kidneys are working. If you have high blood pressure or diabetes, your doctor may ask for these tests regularly so a problem is found early.
Chronic kidney disease has no cure, but treatment can relieve symptoms and stop it getting worse. Many people live with it for years, and complete kidney failure is uncommon. Treatment rests on controlling blood pressure and cholesterol, lifestyle changes and regular follow-up.
Frequently asked questions
Is a headache a sign of high blood pressure?
High blood pressure usually has no symptoms and only rarely causes headaches or blurred vision. The only way to know is to measure it, not to go by how you feel.
My pressure is high at the office but not at home.
That is why several days of home readings or a 24-hour monitor are sometimes requested. Write your numbers down and show them to your doctor.
Are painkillers bad for the kidneys?
Long-term regular use of some painkillers, such as non-steroidal anti-inflammatory drugs, can harm the kidneys. If you take painkillers regularly, tell your doctor.
The first step, a calm conversation.
Go to the booking page or talk to support. Have your earlier results and your medicine list ready.