What Is Orthopnea?

Medically Reviewed by Paul Boyce, MD on January 31, 2022
4 min read

Orthopnea means you find it harder to breathe when you lie down because of fluid in your lungs. It usually comes on over time, but in some cases, it can happen suddenly.

It can wake you up because of a lack of oxygen. But it isn’t the same as sleep apnea. That’s when your throat relaxes as you sleep and blocks your airway. Orthopnea is something you’ll notice more when you’re awake.

You may wheeze when you lie down or have a cough that doesn’t bring anything up. These go away when you sit or stand. You also might find it harder to breathe when you exercise or do normal household chores. You might also:

Orthopnea usually happens because your heart isn’t strong enough to pump out all the blood sent from your lungs. This is called heart failure. Heart disease, cardiomyopathy, high blood pressure, and other problems can cause this weakness.

Heart failure causes fluid to build up around the lungs and eventually to seep in. But why is it worse when you lie down? Think of your lung with this condition as a half-full bottle of water. Stand it up and there’s still a good amount of space for air. Lay it on its side and the water covers one side of the bottle. That’s what happens in your lungs when you lie down and why you feel short of breath.

Also, when you lie down, blood moves from your legs and feet to the chest and belly area. Normally, this isn’t a problem. But a weak heart can’t pump out the extra blood. Because of this added pressure, your lungs might absorb even more fluid than when you were standing.

Though less common, there are also some non-heart related causes of fluid in the lungs. These include:

Your doctor might ask a lot of questions about your breathing. Among them:

  • Do you cough or wheeze when you lie down?
  • Does it get better when you stand?
  • Are your symptoms getting worse over time?
  • How many pillows do you need to sleep comfortably? The more you need, the worse the problem. This is because the more upright you are when you have symptoms, the more fluid there is in your lungs.

Your doctor will also do several tests to find out why you have fluid in your lungs. The first ones they’ll do can include:

  • X-rays. An image of your lungs is the first test your doctor will use to check for fluid in your lungs.
  • Blood tests. Your doctor will take some of your blood to see how much oxygen and carbon dioxide it has. They’ll also see if you have higher than normal levels of B-type natriuretic peptide (BNP). This substance points to whether a heart condition is behind the extra fluid.
  • Echocardiogram. For this test, the doctor will use a handheld wand to get pictures to help trace the beating action of your heart and the flow of blood through the valves.

If your doctor finds that you have orthopnea that’s due to a heart-related cause, they’ll likely suspect heart failure. Then they’ll figure out exactly what condition led to it in order to treat it.

In the short term, you may be able to ease your symptoms if you sit or stand, or raise your upper body with pillows. When your doctor treats you, you’ll get oxygen through tubes into your nose. You may also get a diuretic, which is a medicine that helps your body get rid of extra fluid.

Over the long term, however, it’s best to talk to your doctor about your heart health, the condition that might be the cause of your orthopnea, and how best to treat it.