Hypermobility, hEDS and POTS: Why Bendy Joints and a Racing Heart Travel Together

Why bendy joints and a racing heart show up together

If you have POTS, there is a decent chance a doctor, a physiotherapist or a fellow patient has at some point asked whether you can touch your thumb to your forearm or bend your little fingers back further than seems reasonable. That question is not random. Hypermobility and POTS overlap far more often than chance would predict, and once you see the connective-tissue link between them, a lot of the pattern falls into place.

This is educational field notes, not medical advice. The goal here is to make the connection between hypermobility, hypermobile Ehlers-Danlos syndrome (hEDS) and POTS understandable, so you can track the right things and have a more useful conversation with your clinician. None of it is a substitute for a proper evaluation, and hypermobility on its own is common and usually harmless.

What hypermobility and hEDS actually are

Joint hypermobility simply means some or many of your joints move beyond the normal range. On its own it is extremely common, especially in children, dancers, gymnasts and people of certain ancestries, and for most people it causes no trouble at all. When many joints across the body are affected, clinicians call it generalized joint hypermobility.

Hypermobile Ehlers-Danlos syndrome (hEDS) is a specific clinical diagnosis at the more symptomatic end of that spectrum. It is the most common of the Ehlers-Danlos syndromes, a group of heritable connective-tissue conditions. Unlike several other EDS types, hEDS currently has no confirmed genetic test, so it is diagnosed by clinical criteria published in 2017. Between plain hypermobility and hEDS sits hypermobility spectrum disorder (HSD), a label for people who have symptomatic hypermobility but do not meet the full hEDS checklist. In day-to-day terms, HSD and hEDS are managed much the same way.

The common thread is collagen, the main structural protein in connective tissue. In hypermobility and hEDS, collagen behaves in a more lax, extensible way. Connective tissue is not just in joints. It is in skin, ligaments, the gut wall, and, importantly for POTS, the walls of blood vessels.

How does hypermobility connect to POTS?

Here is the mechanical story, and it is a satisfying one because it is genuinely physical rather than hand-wavy.

Your veins hold most of your blood volume at any moment, and their walls are rich in connective tissue. When you stand up, gravity pulls roughly half a liter of blood downward into the legs and abdomen. In a typical body, the veins have enough wall tension to limit how far they balloon out, and reflexes tighten them further, so blood is pushed back up to the heart. In a more hypermobile, compliant system, the vessel walls stretch more under the same pressure, so they hold onto more blood. That means less blood returns to the heart with each beat, the heart has less to pump, and to keep blood flowing to your brain it does the one thing it can do quickly: it speeds up.

That compensatory speed-up is the tachycardia that defines POTS: a sustained rise in heart rate of at least 30 beats per minute (40 in teenagers) within ten minutes of standing, without a big drop in blood pressure. So in the hypermobile pathway, POTS is less a “broken heart” problem and more a plumbing problem in stretchy pipes.

There is very likely more to it than compliant veins alone. Researchers have proposed contributions from partial small-fiber nerve involvement, low blood volume, and the way pooling in the abdomen (the splanchnic circulation) drains a large reservoir on standing. But the compliant-vessel idea is the cleanest link between the bendy joints and the fast heart, and it explains why the treatments that raise venous return help so directly.

The POTS, hEDS and MCAS “trifecta”

You will often see hEDS and POTS mentioned alongside a third condition: mast cell activation syndrome (MCAS), where immune cells called mast cells release their chemical signals too readily, causing flushing, hives, gut symptoms and reactions to foods, heat or exertion. The clustering of these three is common enough that patients and clinicians call it the trifecta.

Why they travel together is still being worked out, and honesty matters here: the associations are real and repeatedly observed, but the causal wiring is not fully settled. Mast cells sit close to blood vessels and nerves, and the mediators they release, including histamine, can widen vessels and drop blood pressure, which plausibly feeds into orthostatic symptoms. What is practical to know is that if you have one of the three, it is reasonable to stay alert to features of the others, without assuming you must have all three.

If the mast cell side sounds familiar, it is worth reading our deeper look at the POTS, long COVID and MCAS overlap, which walks through the immune piece in more detail.

The Beighton score: what it does and does not tell you

The quickest screen for generalized hypermobility is the Beighton score, a 9-point checklist. It is easy to try at home, but read the caveat first: a high score screens for hypermobility, it does not diagnose hEDS, and a normal score does not rule out a connective-tissue issue.

Here is how the nine points are counted.

A common cutoff for generalized joint hypermobility in adults is 5 or more out of 9, with a slightly higher threshold in children and a lower one in older adults, whose tissues naturally stiffen with age. But diagnosing hEDS itself requires the full 2017 criteria, which add up other features (skin findings, family history, chronic pain, prolapse, and more) and rule out other EDS types. That is a job for a clinician, often a geneticist or a rheumatologist, not a home checklist. If the Beighton screen and your symptoms point that way, it is a reasonable thing to raise, calmly, at an appointment.

Reading the pattern in your own numbers

Whether or not the hEDS label ever gets applied, the mechanism has a practical upside: the hypermobile pathway into POTS is exactly the kind that home tracking is good at catching, because it lives in your standing numbers.

The single most useful thing you can do is a repeatable orthostatic stand test: measure your heart rate and, if you have a cuff, your blood pressure lying down and then again after standing for a few minutes. In the compliant-vessel picture you tend to see a clear heart-rate jump with blood pressure holding roughly steady or dipping only a little, which is the classic POTS signature. Track it across days rather than reading one morning as fate. A single high number after a hot bath, a bad night or a big meal is noise, not a trend.

Two other signals are worth watching over weeks:

• Resting heart rate and morning HRV. In connective-tissue POTS, as in other subtypes, the fast vagal variability that RMSSD captures often runs low and climbs as reconditioning and volume support take hold. Compare same-time-of-day readings against your own rolling baseline, not against a stranger’s numbers.
• How much compression and salt move the needle. Because the mechanism is pooling, interventions that fight pooling should visibly shrink your standing heart-rate rise. If they do, you have found a real lever. If they do not, that is information too.

What changes about management

The good news is that hypermobile POTS responds to the same core toolkit as any POTS, so nothing here is exotic. The emphasis just shifts to match the mechanism.

• Compression, with the waist and abdomen in mind. Because a lot of the pooling is splanchnic (in the abdomen), waist-high or abdominal compression often outperforms calf socks alone. Our guide to compression garments for POTS covers strengths and how to build up tolerance.
• Salt and fluids to expand blood volume. More circulating volume gives stretchy veins less room to hide it. See the science of salt and fluids for how and how much, and clear it with your clinician if you have blood-pressure or kidney concerns.
• Reconditioning that protects the joints. Graded exercise still helps, but hypermobile joints do better starting recumbent or seated (rowing, recumbent cycling, swimming) before moving upright, exactly the shape of the Levine protocol. Strength work for the core and legs also acts as a second muscle pump to push blood upward.
• Physical therapy for joint stability. A physio experienced with hypermobility can teach you to hold joints in a safer range and build the surrounding muscle, which reduces the injuries and pain that otherwise derail reconditioning.
• Pacing. Fatigue is real in this population, and overdoing it triggers setbacks. If post-exertional symptoms are part of your picture, the energy-envelope approach to pacing helps you push without crashing.

Medications (such as those that raise volume, tighten vessels or steady heart rate) are sometimes added, but those are clinician decisions built on your full history, not something to reason out from an article.

Frequently asked questions

Does hypermobility cause POTS? Not in a simple one-way sense, but they are strongly linked. The leading explanation is connective tissue: the same laxity that makes joints bendy also makes vein and vessel walls stretchier, so more blood pools on standing and the heart speeds up. That association is well documented, but most hypermobile people never develop POTS, so treat it as a shared mechanism and risk factor rather than a guaranteed cause.

What is the POTS, hEDS and MCAS trifecta? The observation that POTS, hypermobile EDS (or hypermobility spectrum disorder) and mast cell activation syndrome cluster together more than chance. Many people with one have features of the others. The exact links are still being studied, and not everyone with one has all three.

What is the Beighton score? A 9-point screen for generalized joint hypermobility, checking finger, thumb, elbow, knee and forward-bend flexibility. Roughly 5 or more in an adult suggests hypermobility. It screens only for bendiness and does not diagnose hEDS, which needs the full clinical criteria.

Can you have POTS without Ehlers-Danlos? Yes, very commonly. POTS has several mechanisms and often follows a viral illness with no connective-tissue disorder involved. Many people with POTS have entirely typical joints.

Is hypermobile POTS treated differently? The core toolkit is the same. The emphasis shifts toward abdominal and waist-high compression, recumbent-first reconditioning, and physical therapy for joint stability, all decided with a clinician.

The bottom line

If you are bendy and your heart races when you stand, those two facts are probably linked through the tissue they share. Compliant vein walls let blood pool low, so the heart compensates by speeding up: that is the mechanical bridge between hypermobility and POTS, and it is why the pooling-focused treatments help so directly. The Beighton score can tell you whether hypermobility is in the picture, but it cannot diagnose hEDS, and being flexible is not a verdict. What you can do today is track your standing numbers, watch how compression, salt and gentle reconditioning move them, and bring a clear record to a clinician who can put the whole picture together.