Disclaimer: Human Health is not recommending any specific medical treatment for any particular symptom, nor providing any other medical advice. Always seek the advice of your doctor regarding any medical concern.

POTS, short for postural orthostatic tachycardia syndrome, is a condition that affects up to 1% of people in the United states, estimated to be about 1–3 million people. It is characterized by temporary episodes that occur when transitioning to standing upright, during which the heart rate increases more than is usual for standing up.

What causes POTS to develop?

The cause of POTS is currently unknown. According to community studies, it mostly affects caucasian females between 15–50 years old.

Some theories have been suggested to contribute to the cause of POTS, including changes to nerve activity, hormonal activity, or changes to heart function and blood volume. However, further research is required to definitively determine the exact mechanism behind why POTS develops.

What happens inside the body to cause a POTS episode?

Normally, upon standing up, blood suddenly pools in the legs and abdomen, and this reduces the amount of blood flowing back to the heart. In turn, the amount of blood pumped out of the heart slightly decreases, and so does blood pressure. To compensate for this change, the nervous system acts to increase heart rate and the strength at which the heart beats, to increase blood flow and blood pressure.

This process is known as the ‘normal orthostatic response’, because ‘orthostatic’ means ‘related to upright posture’. This response is typically experienced without symptoms for most people when standing up, although some may experience a slight sensation of dizziness or lightheadedness from time to time.

For people with POTS, their body is not able to regulate their blood pressure as easily upon sudden changes like standing up. A number of factors can contribute to orthostatic intolerance, for example:

• Low blood volume
• Decreased mass of the heart, which can lead to decreased strength of the heart muscle and affects the ability of the heart to pump blood effectively
• Decreased physical activity
• Changes in the levels of hormones and other nervous system signalling molecules, including norepinephrine, renin, and aldosterone
• Damage to the nervous system or decreased nervous system activity
• Atypical immune responses after an illness that can cause dysfunction in the nervous and cardiovascular systems

Due to the dysfunctional changes in blood flow and pressure, the brain doesn’t receive the amount of blood it needs, and this can lead to the characteristic symptoms of POTS such as lightheadedness, fading vision, and feeling faint.

What are the symptoms of a POTS episode?

Common symptoms may include:

• Increased heart rate (tachycardia)
• Lightheadedness
• Palpitations (noticeably rapid, strong or irregular heartbeat)
• Fading vision
• Feeling as if you are about to faint
• Difficulty concentrating
• Headache, particularly around the base of the skull, neck, and shoulders (in a ‘coathanger’ pattern)

Less common symptoms may include:

• Shortness of breath
• Chest pain
• Nausea
• Shaking
• Flushing of the skin
• Blurred vision

Symptoms may be worsened when standing still, after lying down or not moving for periods of time, in the morning, in hot weather, during an illness, or during menstrual periods.

Want to keep track of how your POTS episodes affect you?

If you are or think you may be experiencing symptoms of POTS, keeping a record of your episodes and any treatments you may be taking can be challenging. Using a health tracker might save you from trying to remember all that information under pressure during an appointment, and help give your clinician an accurate picture of your experiences, so that you can make more informed decisions about your care together.

Human Health is a free health tracking app that makes it easy to track the impact of your symptoms, and keeps a record of your treatments, as well as providing you with reminders about when they’re due. The app can provide you with key insights about how your symptoms are changing over time.

Click here to download Human Health.

We hope you found this article helpful. If you know someone who could benefit from learning about what happens during a POTS episode, please share this article with them. We’d love for our resources to reach those who need them.

Resources

1. UpToDate. Postural tachycardia syndrome. Available at: https://www.uptodate.com/contents/postural-tachycardia-syndrome
2. MSD Manual, Professional Version. Orthostatic Hypotension. Available at: https://www.msdmanuals.com/professional/cardiovascular-disorders/symptoms-of-cardiovascular-disorders/orthostatic-hypotension

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