POTS and hypermobility: when circulation and connective tissue drag the gut along

Healthy state

Connective tissue holds the body together: joints and skin, but also the walls of blood vessels, stomach and gut. How stretchy it is is partly inherited. Many people are somewhat hypermobile without ever having problems from it.

When pain and other symptoms come on top of hypermobility, specialists speak of hypermobility spectrum disorder (HSD). Hypermobile Ehlers-Danlos syndrome (hEDS) is the most strictly defined form; fixed clinical criteria have applied since 2017. Unlike the other EDS types, no causative gene is known for hEDS, so the diagnosis is made using the criteria.

When you stand up, gravity pulls part of your blood into the legs and belly. The autonomic nervous system corrects this within seconds: blood vessels tighten and the heart beats a little faster. In postural orthostatic tachycardia syndrome POTS Postural orthostatic tachycardia syndrome: the heart rate rises by at least 30 beats per minute on standing without a drop in blood pressure, with light-headedness and exhaustion. (POTS), by contrast, the heart rate rises by at least 30 beats per minute on standing, 40 in adolescents, without a drop in blood pressure. Light-headedness, palpitations, exhaustion and trouble concentrating come with it.

Typically affected are young women; it often starts in adolescence or after a viral infection. In a large online survey of 4,835 people, the median time to diagnosis was two years. The same autonomic nervous system also runs the belly: how fast the stomach empties, how the gut waves travel and how well the gut is supplied with blood.

Disrupted state: causes and effects

In British gastroenterology clinics, one in three newly referred patients (180 of 552) had previously unrecognised hypermobility with symptoms. They more often had heartburn, acid regurgitation and fullness after meals. In a follow-up study, hypermobility was more common in functional disorders than in organic disease (39 versus 27.5 per cent), most clearly in functional dyspepsia with fullness.

At the Mayo Clinic, 56 per cent of 687 people with EDS had gut symptoms, most often abdominal pain, nausea, constipation, heartburn and IBS Irritable bowel syndrome Recurring abdominal pain linked to bowel movements, without tests finding another cause. Today it is understood as a disorder of gut–brain interaction. More in the chapter “The gut-brain axis”-like symptoms. Where gastric emptying was measured, it was abnormal in 22 per cent, about as often too slow as too fast. In 18 of 30 people whose rectum was examined, a pelvic floor evacuation disorder was found.

In POTS, too, gut symptoms are among the most common complaints. A systematic review found delayed gastric emptying to be the most frequent finding, but stressed that when stomach movement is normal, functional disorders such as functional dyspepsia or IBS are usually the explanation. In an analysis of 1,044 people with hEDS/HSD, one group had both functional dyspepsia and IBS; this group more often had POTS, more autonomic symptoms, more anxiety and poorer quality of life.

Why this happens is not clear. Proposed explanations include stretchier connective tissue in the gut wall, altered control by the autonomic nervous system, heightened pain sensitivity, and drugs such as opioids that slow the gut. In the British study, upper abdominal symptoms were linked mainly to autonomic symptoms and chronic pain.

Forums and some practices talk about a "trifecta" of hEDS, POTS and mast cell activation syndrome Mast cell activation syndrome (MCAS) A rare condition with repeated attacks caused by mast cell messengers in several organs. The diagnosis needs lab evidence during an attack. More in the chapter “Mast cells: alarm cells in the gut, histamine and the disputed MCAS” (MCAS). The evidence for it is thin: a review found no solid studies for a shared mechanism, and a 2026 paper concluded there is no evidence that MCAS is more common in POTS or hEDS. How MCAS is properly diagnosed is covered in the chapter on mast cells Mast cells Immune cells beneath the skin and mucous membranes, filled with histamine and other messengers. They raise the alarm in allergies, infections and stress. More in the chapter “Mast cells: alarm cells in the gut, histamine and the disputed MCAS”.

Specialists increasingly warn about overtreatment: many drugs at once, ever stricter diets, even tube or intravenous feeding before simpler steps have been tried. Malnutrition and avoidant/restrictive food intake disorder (ARFID ARFID Avoidant/restrictive food intake disorder: someone eats too little or too narrowly, not because of body shape or weight, but out of fear of symptoms, low appetite or aversion to tastes and textures. More in the chapter “Fear of food: when your list of safe foods keeps shrinking”) are common in this group. A study of 670 people showed that it is mainly fear of symptoms when eating that makes eating-disorder questionnaires flag positive.

One finding for anyone who suspects small intestinal bacterial overgrowth Small intestinal bacterial overgrowth (SIBO) Too many bacteria in the small intestine, where normally few live. Bloating and diarrhoea are typical; it is usually diagnosed with a breath test. More in the chapter “When the small intestine is too densely colonised”: in a London clinic, not a single person with hEDS had a positive hydrogen breath test Breath test After drinking a sugar solution, hydrogen and methane in the breath are measured several times. This can reveal sugar intolerances and signs of bacterial overgrowth. More in the chapter “Gut tests: what they show and what they do not”.