Your blood usually flows at a steady rate, whether you're sitting, standing, lying down, or hanging upside-down from a tree branch in the backyard. But if that rate changes when you change positions, that’s a condition called orthostatic intolerance, or OI.
It can make you feel dizzy, lightheaded, or faint, especially when you stand up after lying down.
Postural orthostatic tachycardia syndrome (POTS) is a disorder that has OI as its most common symptom. When you have POTS, most of your blood stays in the lower part of your body when you stand up. This makes your heart beat faster to try to get blood to your brain. Your heart rate can go up by 30 beats or more a minute after you stand up. As that happens, your blood pressure is likely to drop.
Scientists aren’t sure exactly why, but women between 15 and 50 years old are more likely to have POTS.
When your heart has to work that hard and your blood pressure falls, that can throw other body functions off balance. You might:
- Feel dizzy or faint
- Have blurry vision
- Feel nauseous or shaky
- Throw up
- Sweat a lot
- Have brain fog
- Chest pain
- Feeling hot or cold
- Feeling anxious, nervous, or jittery
- Headaches and neck pain
- Unusual color in hands and feet
- Diarrhea or constipation
You might be more likely to notice these when you're in the shower, standing in line, or feeling stressed. You also may have POTS symptoms after you eat because your intestines need more blood flow for digestion.
Researchers are still working to understand exactly why it happens, but several diseases and conditions seem to make you more likely to have POTS. These include:
- Anemia (when you don’t have enough red blood cells)
- Autoimmune diseases, like Sjogren’s syndrome or lupus
- Chronic fatigue syndrome
- Diabetes and prediabetes
- Ehlers-Danlos, a muscle and joint condition
- Infections like mononucleosis, Lyme disease, or hepatitis C
- Multiple sclerosis
- Click-murmur syndrome (also called mitral valve prolapse)
With such different symptoms, POTS can be hard to diagnose. A tilt-table test is thought to be the best way to test for it.
Your doctor will ask you to lie on a table and strap you in so you won’t fall when it tilts. The table starts in the horizontal position, then slowly moves to vertical to simulate standing up. Your doctor will watch for changes in your heart rate.
Some people who have POTS may faint during this test. It’s important to work with a doctor who’s very familiar with the condition. This might be a heart doctor (cardiologist) or a doctor who specializes in problems with your nerves and muscles (neuromuscular specialist).
There's no cure for POTS, but various things can help with your symptoms.
Compression stockings. These help push the blood up from your legs to your heart. You’ll want ones that provide at least 30-40 minutes of compression and go all the way up to your waist, or at least up to your thighs. Your doctor can prescribe a pair.
Diet. Salt and water are key. They keep fluids in your body and raise the amount of blood in your body. Think pickles, olives, nuts, and salted broths. Eat smaller meals more often with a healthy balance of protein, vegetables, fruits, and dairy.
Lifestyle. Plan ahead: If you get tired easily, you may not always have the energy to take care of yourself. Learn how to take your own pulse and blood pressure. Ask your doctor what your numbers should be, and check them regularly.
Communication. POTS can make simple activities a bit harder, and that can be frustrating and stressful. A support group or therapist may help you manage the emotional issues the condition can cause.