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High Blood Pressure

Having high blood pressure puts you at increased risk whilst diving. It is a major risk factor for having a heart attack or a stroke, both of which could be fatal underwater. Over time, high blood pressure can damage the blood vessels in the body, and the heart muscle itself. These structures stop working exactly as they should do, which puts you at risk of a condition called immersion pulmonary oedema.

Small blood vessels in the eye and the kidneys may also be damaged.

You may be passed fit to dive by a doctor if your blood pressure is well controlled, your overall health is good, and there is no evidence of any heart, kidney or eye damage.

If you are taking medications for high blood pressure having had a heart problems or a stroke in the past, please do read the relevant ‘Can I dive with…?’ sections.

Immersion Pulmonary Oedema

Pulmonary oedema is the build up of fluid on the lungs. In immersion pulmonary oedema, there is a relatively sudden accumulation of fluid in the lungs caused by the effects of submersion in water on the body’s blood vessels and the heart. This can cause significant shortness of breath, chest pain and a cough. It is often fatal. It is a rare condition and is difficult to predict, but high blood pressure is a major risk factor. It usually requires treatment in hospital as an emergency and can mean you have to abort a dive suddenly, which increases your risk of decompression illness.

Cardiovascular risk

Your cardiovascular risk (your risk of heart attack or stroke) is affected by many factors. These risk factors include obesity (determined by your body mass index – BMI), your smoking status, male gender, your blood pressure, your cholesterol levels, whether you are diabetic, and your family history.

My blood pressure is well controlled – can I dive?

You may be passed fit to dive, but it will require assessment by a diving doctor.

The first step will be to book a telephone consultation to discuss your medical history, including any other cardiovascular risk factors that you may have.

Depending on whether you have had a medical before, you may then need to attend for a Sports Diver Medical with one of our doctors.

What extra tests might the doctor need?

During your telephone consultation the doctor will advise you on the next steps, and any further information required.

This might typically include:

  • Asking your GP for a summary of your medical records
  • Blood test results – especially your blood count, kidney function, cholesterol levels, Hba1c (diabetes test)
  • A urine test (urine ACR)
  • An electrocardiogram (ECG) – an electrical tracing of your heart, which can be done here as part of a medical
  • A recent opticians report on the health of your eyes, or photos or the backs of your eyes

This list is not exhaustive, and additional tests (for example chest X-ray, echocardiograms) may be required depending on your exact circumstances.

My blood pressure only goes up when I see a doctor!

So called ‘white coat hypertension’ is very common. If you know this applies to you, it may be easiest to purchase a home blood pressure monitor from a pharmacy or online, and keep a diary of your readings when you are relaxed at home.

Alternatively, your GP surgery may have a meter in the waiting room that you can use at your convenience.

You can then show this to the doctor here, if needed.