October 17, 2022 - Written By: Maria Arini Lopez, PT, DPT
Postural orthostatic tachycardic syndrome (POTS) is quite the mouthful. It also results in unpleasant symptoms of dizziness and rapid heart rate (tachycardia) with changes in position, especially from lying down to sitting up and sitting to standing (postural orthostasis).
POTS is one of the many possible symptoms of dysautonomia, a disorder affecting the autonomic nervous system (ANS).
Under normal conditions, the ANS effectively balances heart rate and blood pressure, allowing blood flow through the body (especially to the brain) at an even pace, regardless of whether you are lying down, sitting, standing, or in a headstand during a yoga class.
With POTS, the ANS cannot successfully coordinate the events—namely, blood vessel constriction and heart rate response—required to maintain even blood flow throughout the body during positional changes.
Blood Storage with Positional Changes
At any one time, around 60% of your blood is stored in your veins, particularly those in your legs, while arteries, arterioles (smaller arteries), and capillaries (tiny blood vessels) store approximately 20% of the blood.
When you stand up from lying down, especially if it is quickly done, gravity causes a certain amount of blood (normally between 10-15% more) to pool in the veins in the legs, arms, and abdomen, which are all now lower than heart level. This causes the veins to expand or dilate in response to increased storage.
One would assume that connective tissue disorders such as Ehlers Danlos Syndrome might allow even greater expansion of the veins due to increased blood storage with gravity, leading to greater blood pooling and more noticeable POTS symptoms, including fatigue, headaches, brain fog, and fainting spells.
Failure of the ANS
The problem with POTS arises when the ANS does not react fast enough to cause the veins to constrict or get smaller to increase the blood pressure necessary to push the blood upward to the heart and lungs to become oxygenated again.
Because the entire system is now backed up, the brain is looking for oxygenated blood, which is now being delivered at a slightly slower pace than before. This results in those disconcerting sensations of dizziness or lightheadedness after moving to an upright position.
To compensate for the ANS dysfunction, the body releases hormones, epinephrine (adrenaline) and norepiphrine to jump start the heart to beat more rapidly and forcefully to supply more blood to the brain ASAP. This also increases blood pressure throughout the circulatory system to get blood flowing at an even pace again.
Diagnosis
The primary way POTS is diagnosed is the tilt table test, which measures heart rate and blood pressure with positional changes. This test often takes around 90 minutes to complete, although it may be much shorter depending on individual responses to the test. POTS is officially diagnosed if your heart rate increases to 30 beats per minute or more within 10 minutes of changing positions.
Tips for POTS Relief
No known cure exists for POTS at this time; however, certain things may help with reducing POTS symptoms.
Wearing compression socks and pelvic/abdominal compression garments may assist in pushing blood up from the legs and abdomen.
Exercising, especially isometric exercises (when you contract your muscles without moving anywhere such as pushing against a wall) may strengthen the core and leg muscles to allow them to pump blood from the veins up to the heart and brain more efficiently.
A diet high in salt (10,000 mg/day) with plenty of water (2 to 2.5 liters/day) for hydration may increase blood volume, minimizing drops in blood pressure with positional changes.
Eating smaller meals more frequently throughout the day may help relieve POTS symptoms which worsen after a large meal. After you eat a large meal, lots of blood rushes to the digestive system to help in the process of breaking down food and carrying nutrients to the regions of the body that need them.
Training yourself to move slowly while changing positions and waiting a little bit before immediately walking or standing is important to avoid fainting spells and possible injury. I usually recommend to my patients with POTS to do some ankle pumps or knee extensions on the side of the bed to pump blood from the legs upward to the heart.
Breathing exercises may help decrease POTS symptoms.
Elevating the head of the bed by 6 to 10 inches so that you are lying on an angle might help to minimize POTS symptoms after sleeping since your legs are already lower than your heart in this position.
It is recommended to avoid alcohol which dehydrates the body and dilates or widens blood vessels, both of which worsen POTS symptoms.
Medications
Your doctor may also prescribe some medications, such as midodrine, fludrocortisone, pyridostigmine, and beta-blockers, which have been known to decrease certain POTS symptoms.
Bottom Lines
Move slowly when changing positions. Enjoy salty snacks and drink lots of water. If tolerated, moderate exercise to strengthen the leg and core muscles and compression garments may be helpful in relieving POTS symptoms.
To learn more about orthostatic intolerance, listen to this recording of Dr. Peter Rowe, cardiologist at Johns Hopkins. The recording can be accessed at https://www.ehlers-danlos.com/support-echo/.
References and Resources
Postural orthostatic tachycardia syndrome (POTS). Cleveland Clinic. Accessed October 12, 2022.
The relative volumes of arteries and veins considered as percentages of total blood. Research Gate. Accessed October 12, 2022.
Tilt table test. Cleveland Clinic. Accessed October 12, 2022.
Mayo Clinic Q and A: All about POTS. Mayo Clinic. Accessed October 12, 2022.
Kavi L. Postural tachycardia syndrome: multiple symptoms, but easily missed. British Journal of General Practice. 2012;62(599):286–287. doi: 10.3399/bjgp12X648963
Maria Arini Lopez, PT, DPT
Maria Arini Lopez, PT, DPT, CSCS, CIMT, CMTPT is a freelance medical writer and Doctor of Physical Therapy from Maryland. She has expertise in the therapeutic areas of orthopedics, neurology, chronic pain, gastrointestinal dysfunctions, and rare diseases, especially Ehlers Danlos Syndrome.