Postural orthostatic tachycardia syndrome (POTS)

When you stand, gravity pulls blood down into your legs and abdomen. To keep enough blood flowing to your brain, your body reacts automatically within seconds: your blood vessels tighten and your heart speeds up slightly.

This is controlled by your autonomic nervous system, the "automatic" system that runs the things you never think about, like heart rate, blood pressure, and digestion.

In POTS, this automatic balancing system does not work as it should. When you stand:

1. Blood pools in your legs and lower body instead of flowing back up.
2. Your heart races to make up for the blood that isn't reaching the upper body and brain.

This can leave you feeling lightheaded, exhausted, or foggy. Because gravity is the trigger, lying down usually restores normal blood flow and eases symptoms quickly.

POTS is one of several types of dysautonomia, a group of conditions in which the autonomic nervous system is out of balance.

Symptoms usually get worse when you stand and better when you sit or lie down. While it can vary from person to person, common symptoms include:

• Dizziness or lightheadedness when standing
• A racing or pounding heart (palpitations)
• Feeling close to fainting, or fainting
• Tiredness that does not match your activity level
• Brain fog, including trouble concentrating, remembering, or finding words
• Blurred or dim vision when standing
• Headache, often at the back of the head or neck
• Nausea or digestive issues
• Shortness of breath when standing
• Cold, red, or purple feet and legs when standing
• Unrefreshing sleep, leaving you tired even after a full night's rest

Many people notice their symptoms are worse:

• First thing in the morning
• In heat, or after a hot shower
• After a large meal, especially a heavy or high-carbohydrate one
• Standing still for long periods
• During or right before a menstrual period
• While recovering from another illness or infection

The exact underlying cause of POTS is not yet fully understood, but researchers believe it involves several overlapping mechanisms in the body:

• Nerve dysfunction: The nerves that signal blood vessels in your legs to tighten may not function properly.
• Low blood volume: Some individuals with POTS have less circulating blood than normal.
• Overactive stress response: The body’s "fight-or-flight" system may produce excess stress hormones, keeping the heart rate elevated.
• Immune system activity: Autoimmune responses, where the body mistakenly attacks its own tissue, may play a role, particularly after an infection.

POTS frequently develops after a major stress on the body, such as an illness or surgery. The most common triggers include:

• Viral or bacterial infections, including COVID (POTS is a recognized condition following viral illnesses, though how often it occurs varies across studies)
• Major surgery or physical trauma
• Pregnancy
• Extended bed rest or prolonged immobility

It is important to know that POTS is a real, physical medical condition. It is not caused by anxiety, nor is it the result of simply being "out of shape", two frequent misunderstandings. While anxiety can exist alongside POTS, and prolonged inactivity can make symptoms feel worse, neither is the cause of the condition.

Anyone can get POTS, but it most often affects women, usually between the ages of 15 and 50. POTS is more common in people who also have:

• Hypermobility, meaning very flexible joints
• Mast cell activation syndrome (MCAS)
• Long COVID or other post viral conditions
• Some autoimmune conditions

POTS is diagnosed when all of these apply:

• Your heart rate rises by at least 30 beats per minute within 10 minutes of standing up (at least 40 beats per minute for those aged 12–19), and stays up
• Your blood pressure does not drop significantly when you stand (no sustained fall of about 20 mmHg in the top number or 10 mmHg in the bottom number)
• You have symptoms when upright and have had them for at least three months
• No other condition better explains your symptoms

The stand test. The most common way to check is a stand test. You lie down and rest for a while, then stand up. Heart rate and blood pressure are measured while lying down and several times over 10 minutes while standing. It can be done at a clinic, or at home with a blood pressure monitor and clear instructions.

Ruling out other causes. Other conditions, such as thyroid problems, anaemia, or dehydration, can cause similar symptoms, so it is important to check for them.

There is no single cure for POTS, but treatment helps many people feel noticeably better. It is usually a combination of everyday measures and, when needed, medicine.

Everyday measures. These are the foundation for almost everyone:

• More fluid. Drink a large glass of water before getting out of bed in the morning.
• More salt. Extra salt helps the body hold on to fluid; consensus guidance is often around 10–12 g of salt a day. Talk to a doctor first if you have high blood pressure, or heart or kidney disease.
• Get up slowly. Sit on the edge of the bed for a minute before you stand.
• Compression garments. High-waisted compression tights or an abdominal binder help stop blood pooling in the legs and belly.
• Smaller, more frequent meals. Large meals, especially high-carbohydrate ones, draw blood to the gut and can make symptoms worse.
• Avoiding heat where you can.
• Physical counter-measures. Crossing your legs, clenching your thigh and buttock muscles, or rising on your toes while standing can help.
• Sit for tasks you usually stand for, like showering, cooking, or brushing your teeth.
• Lie down when symptoms build up, before they get bad.
• Keep a simple symptom diary. It helps you spot triggers and shows your doctor how you are doing.

Medicines. If everyday measures are not enough, medicines can help. Some lower the heart rate, others help the body hold on to fluid, and others help blood vessels tighten. Which medicine suits you depends on your symptoms, your other conditions, and your blood pressure, so it needs to be decided together with a doctor.

POTS varies a lot from person to person. Many people improve over time, especially with treatment. For others it lasts longer, and the goal is to feel and function as well as possible.

Call or go to the emergency department if you have:

• Chest pain or pressure
• Fainting during physical exertion
• Fainting that leads to injury
• Severe shortness of breath
• A very fast or irregular heartbeat that does not settle when you lie down
• Sudden weakness, numbness, or trouble speaking

Contact your clinic if:

• You faint for the first time
• Your symptoms are new or getting clearly worse
• Someone in your family has died suddenly at a young age, or has a known heart rhythm problem