Dysautonomia and EDS: When Your Nervous System Loses Its Footing
What Is Dysautonomia?
Dysautonomia is a broad term for dysfunction of the autonomic nervous system — the system that regulates your body's automatic functions including heart rate, blood pressure, digestion, breathing, temperature regulation, and sweating. When this system doesn't work properly, the effects can touch virtually every part of daily life.
POTS — postural orthostatic tachycardia syndrome — is the most commonly discussed form of dysautonomia in the EDS community. But dysautonomia encompasses a much wider spectrum of presentations. Not everyone with dysautonomia has a racing heart when they stand. Some people's primary experience is temperature dysregulation, inability to sweat normally, digestive motility issues, or dizziness without significant heart rate changes.
Why EDS and Dysautonomia Overlap
The autonomic nervous system itself depends on connective tissue for structural support. In EDS, where connective tissue is structurally compromised throughout the body, the nerves and vessels that carry autonomic signals can be affected. Additionally, the blood vessel walls in EDS are more extensible than normal — affecting how efficiently blood is distributed when the body changes position or temperature.
MCAS adds another layer of complexity. Mast cells are present throughout the autonomic nervous system, and when they are dysregulated they can directly affect the signals that control heart rate, blood pressure, temperature regulation, and gut motility. Addressing mast cell activation often produces meaningful improvement in autonomic symptoms — which is why treating the full triad matters rather than each condition in isolation.
Temperature Dysregulation — An Underrecognized Symptom
The inability to sweat normally — anhidrosis or hypohidrosis — is a form of autonomic dysfunction that receives far less attention than heart rate issues but can be equally disabling. Sweating is the body's primary cooling mechanism. When it doesn't work properly, even moderate heat exposure can become dangerous. This has particular implications for exercise, travel, and any activity in warm environments.
In people with EDS and MCAS, temperature changes can also trigger mast cell reactions — as with PMLE and sun sensitivity — creating a compounding effect where both autonomic dysregulation and immune response are occurring simultaneously in response to environmental temperature shifts.