Postural Orthostatic Tachycardia Syndrome (POTS) is a disorder involving a malfunction of the autonomic nervous system (ANS), which controls involuntary functions like heart rate and blood pressure. POTS is defined by an abnormally large increase in heart rate upon standing, accompanied by symptoms of orthostatic intolerance. While the primary symptom is this excessive heart rate increase, patients frequently report sensory disturbances, including numbness and tingling (paresthesia). These sensations are common experiences, and understanding their origin—whether transient effects of poor circulation or signs of an underlying neurological issue—is important.
How Autonomic Dysfunction Affects Sensation
The autonomic nervous system’s inability to properly regulate blood vessel constriction directly causes temporary sensory changes in POTS patients. When a person with POTS stands up, gravity pulls blood downward. The blood vessels in the lower body fail to tighten sufficiently to push blood back toward the heart and brain, resulting in significant blood pooling (venous stasis) primarily in the legs and feet.
This pooling reduces the volume of blood circulating back to the central nervous system and causes reduced blood flow (hypoperfusion) to the distal extremities. This temporary lack of adequate oxygen and nutrient delivery to the nerves can trigger transient sensory symptoms. Patients often describe this as positional numbness or tingling, sometimes accompanied by coldness or a purplish discoloration of the feet (acrocyanosis) when standing. These sensations are short-lived and resolve quickly when the patient lies down, allowing blood flow to redistribute.
Related Conditions That Cause Neuropathy
When numbness and tingling are persistent rather than transient, the cause is frequently a co-occurring condition, most notably Small Fiber Neuropathy (SFN). SFN involves damage to the small nerve fibers responsible for transmitting pain, temperature, and autonomic signals. This condition is estimated to affect up to half of POTS patients.
SFN symptoms are more chronic and intense than temporary tingling from blood pooling, often presenting as burning, electrical, or sharp pain. These sensations typically begin in the feet and progress upward, but they can also affect the hands and face.
Common Comorbidities
Other conditions seen alongside POTS can also contribute to neuropathic symptoms. Hypermobile Ehlers-Danlos Syndrome (EDS), a connective tissue disorder, is a common comorbidity that can lead to nerve compression due to joint instability. Chronic illnesses associated with POTS may also cause nutritional deficiencies, such as a lack of Vitamin B12, which is known to cause peripheral neuropathy. Persistent sensory changes require a broad evaluation to determine if they stem from the primary POTS mechanism or a secondary diagnosis.
Diagnosis and Management of Sensory Changes
Determining the precise cause of numbness and tingling in a POTS patient requires distinguishing between transient circulatory issues and chronic nerve damage. The initial evaluation often includes a Tilt Table Test, which is the standard procedure for confirming POTS and observing symptoms during controlled postural change. This test helps establish if sensory changes are triggered by the upright position and associated blood flow irregularities.
To investigate chronic nerve issues, physicians use specialized tests. Nerve conduction studies are employed to rule out large fiber neuropathy. The most definitive test for Small Fiber Neuropathy (SFN) is a skin punch biopsy, which measures the density of small nerve fibers in the skin and is considered the gold standard for diagnosis.
Management of sensory symptoms focuses on the underlying cause. For transient, circulation-related symptoms, treatment focuses on managing the POTS itself. This includes lifestyle adjustments such as significantly increasing fluid and salt intake to boost blood volume. Wearing medical-grade compression garments, particularly on the lower extremities, helps counteract blood pooling and directly alleviates positional numbness and tingling. If SFN is confirmed, treatment is directed at the neuropathy, which may include specific medications to address neuropathic pain or immunotherapies if an autoimmune cause is suspected.