POTS and hypovolemia

Dysautonomia is dysfunction of the autonomic nervous system, which controls essential functions like heart rate, blood pressure, digestion and body temperature. There’s an overlap between all types of symptomatic hypermobility and dysautonomia.

POTS, or Postural Orthostatic Tachycardia Syndrome, is the best-known form of dysautonomia. People with POTS may have a range of symptoms, like heart palpitations, dizziness, brain fog, headache, and gastrointestinal issues. It’s diagnosed by a 30 beat per minute heart rate increase (40 beat increase for teens) that happens in the first 10 minutes after moving from lying down to an upright position. Due to the autonomic dysfunction, the heart has to work harder against gravity to pump blood up to the heart and head, leading to the sudden heart rate and symptom spike.

A common physiologic sign in POTS is hypovolemia, or decreased blood volume. A first-line fix is expanding blood volume through fluid and electrolytes. Generally, the recommendations are 2-3 liters of water, and up to 10 grams of salt(1) but there are a few caveats there. For most people, a mix of electrolytes, like sodium, potassium and even a little magnesium will work better than just salt. There are a range of electrolyte products that can help, and most of the time, it makes sense to increase fluids and electrolytes together and gradually. If you only increase fluids, you’ll just be making more bathroom visits.

It’s always a good idea to talk to your doctor, dietitian and health care team first and check in with them along the way, because some conditions like kidney disease, heart problems, or even symptoms of long COVID require special tailoring of the recommendations.

A few small studies suggest that a gluten-free or a low glycemic diet may be helpful for people with POTS.2,3 Checking in with a trained dietitian or nutrition professional can help ensure you’re still getting the nutrients you need.

by C Harris MPH RD

SEDSConnective adviser

1 Raj SR, Guzman JC, Harvey P, et al. Canadian Cardiovascular Society position statement on postural orthostatic tachycardia syndrome (POTS) and related disorders of chronic orthostatic intolerance. Can J Cardiol. 2020;36(3):357-372. doi:10.1016/j.cjca.2019.12.024

2. Zha K, Brook J, McLaughlin A, Blitshteyn S. Gluten-free diet in postural orthostatic tachycardia syndrome (POTS). Chronic Illn. 2023;19(2):409-417. doi:10.1177/17423953221076984

3. Breier NC, Paranjape SY, Scudder S, et al. Worsening Postural Tachycardia Syndrome Is Associated With Increased Glucose-Dependent Insulinotropic Polypeptide Secretion. Hypertension. 2022;79(5):e89-e99. doi:10.1161/HYPERTENSIONAHA.121.17852