Sleep Apnea and High Blood Pressure: The Hidden Link

If your blood pressure stays high even though you take your tablets every day, there is one cause many people never get checked for: what happens to your breathing at night. Obstructive sleep apnea and high blood pressure are closely linked, and treating the sleep problem can make the blood pressure easier to control.

How sleep apnea pushes blood pressure up

In obstructive sleep apnea the throat closes for ten seconds or more, again and again through the night. Each time it happens, oxygen falls and the body reacts as if it is under threat: the stress (sympathetic) nervous system fires, the heart speeds up and the blood vessels tighten. Blood pressure jumps with every pause.

Normally blood pressure dips by about 10 to 20 percent during sleep, a rest period for the heart and arteries. In people with untreated sleep apnea that night-time dip is often blunted or lost, and the constant stress signals carry over into the day. Over months and years, that becomes sustained high blood pressure.

Signs your blood pressure may be linked to your sleep

• Your blood pressure stays high despite three or more medicines taken correctly. Doctors call this resistant hypertension, and studies have found sleep apnea in a large share of these patients.
• Your morning readings are higher than your evening readings.
• You snore loudly, or someone has seen you stop breathing or gasp at night.
• You wake with a headache or feel unrefreshed after a full night.
• Your home monitor or a 24-hour blood pressure test shows your pressure does not fall at night.

Major cardiology guidelines recommend screening people with resistant hypertension for obstructive sleep apnea for exactly this reason.

Does treating sleep apnea lower blood pressure?

For many people, yes, though it is not a replacement for blood pressure medicine. Research on CPAP therapy shows an average fall of a few points, with larger drops in people who have resistant hypertension, severe sleep apnea and who use the machine every night. Just as important, treatment can restore the healthy night-time dip and reduce the stress surges that strain the heart.

The key word is "use". The benefit comes to people who wear CPAP for most of the night, every night. A comfortable mask and the right pressure, set by a proper CPAP titration or an auto CPAP, make that possible.

What to do next

1. Keep taking your blood pressure medicines. Never stop or change them without your doctor.
2. Check your readings at home, morning and evening, for a week and note them down.
3. Ask your doctor about a sleep test if you snore, feel tired, or your pressure is hard to control.
4. Get tested. For most adults a home sleep study in your own bed is the simplest first step. You can also start with our 1-minute snoring check.

Frequently asked questions

Can sleep apnea cause high blood pressure in young people?

Yes. Sleep apnea is not only a problem of older people, and it is one of the causes doctors look for when blood pressure is high at a young age.

Will CPAP let me stop my blood pressure tablets?

Usually not completely. Treatment can lower blood pressure and sometimes means fewer or lower doses, but only your doctor can decide that after checking your readings.

Which test checks for sleep apnea?

A sleep study. It records breathing, oxygen and heart rate overnight and gives an AHI, the number of breathing events per hour. See our sleep apnea test in Chennai.

Related: sleep apnea and heart problems, sleep apnea and diabetes. See all sleep study options and prices in Chennai.