POTS and orthostatic intolerance

What it is

Postural orthostatic tachycardia syndrome is a sustained excessive rise in heart rate on standing - typically thirty beats per minute or more in adults - without a fall in blood pressure, accompanied by symptoms of light-headedness, palpitations, fatigue and brain fog.

Several mechanisms produce it: blood pooling in the legs and abdomen, low blood volume, excessive sympathetic activation, and in some people autonomic nerve damage. Deconditioning is both a consequence and a contributor - reduced cardiac size and blood volume make the problem worse, which is why graded, recumbent-first exercise training is one of the most effective treatments.

What it feels like

• Heart racing or pounding within minutes of standing
• Light-headedness, greying vision and a need to sit or lie down
• Profound fatigue, particularly after being upright
• Brain fog, difficulty concentrating and word-finding problems
• Worse in the morning, in heat, after meals and around periods

What causes it

Most people have more than one of these at once, and they feed each other. Read the list looking for the two or three that sound like your week rather than for the one true answer — the ones that describe you are the ones worth acting on.

Blood pooling in the legs and abdomen

On standing, a large volume shifts downward. In POTS, excessive pooling means less blood returns to the heart, and the heart rate rises steeply to compensate for the reduced filling.

Low blood volume

Many people with POTS have measurably reduced blood volume, which means less reserve on standing. It is part of why increased fluid and salt intake helps.

Excessive sympathetic activation

In some people the compensatory response overshoots, producing a large heart rate rise and the palpitations, tremor and anxiety-like symptoms that accompany it.

Deconditioning

Reduced upright activity leads to a smaller heart and reduced blood volume, both of which worsen orthostatic tolerance. It is a genuine self-reinforcing loop and it is the part exercise training breaks.

Onset after a viral illness

A large proportion of cases follow an infection, and POTS has become far more commonly recognised since COVID. The onset is often abrupt and datable.

Joint hypermobility

POTS is substantially more common in people with hypermobile Ehlers-Danlos syndrome and hypermobility spectrum disorder, probably through more compliant blood vessels allowing greater pooling.

Autonomic neuropathy

In a subgroup, damage to the small nerves controlling blood vessels in the legs prevents proper constriction on standing. This form behaves somewhat differently and is worth identifying.

Prolonged bed rest

Any extended period lying down produces orthostatic intolerance. It is a common precipitant after a long illness or hospital stay.

Heat, meals and hormonal changes

All three shift blood away from the central circulation. Symptoms characteristically worsen in hot weather, after eating and premenstrually.

Being told it is anxiety

The palpitations, tremor and light-headedness look like anxiety, and it is a common misattribution that delays diagnosis by years. Anxiety often coexists as a consequence rather than as the cause.

Who tends to get it

• Young women, in whom it is most commonly diagnosed
• Anyone with joint hypermobility, in whom it is substantially more common
• People recovering from a viral illness, including COVID
• Anyone who has had a long period of bed rest or immobility
• People with autoimmune conditions, which are associated

What makes it worse, and what settles it

The qFIT routine for this

Ready-made routineGentle Start (Fatigue & Flare-Ups)

qFIT already has this one built. It runs massage first, then stretching, then strength — the order that works on a body that is already sore — and every activity in it carries the reason it is there.

The button below opens your Checklist with this routine already selected, so instead of your whole list you land on just its Categories, Targets and Exercises, each with its checkbox, ready to tick as you work through them.

Have more than one problem? Tick yours under My Problems on My Profile and your Checklist's Routine list gains Recommended for my problems — every routine for the problems you picked, merged into one. Your picks stay private; that filter is the only thing they feed.

Get it checked if…

Fainting with injury, chest pain, or new arrhythmia needs cardiology review before exercising

And whatever the body part: chest pain or unusual breathlessness on exertion; a fever alongside the pain; unexplained weight loss; pain that is constant and unrelated to how you move; new numbness, weakness or loss of bladder or bowel control; or one calf that is swollen, warm and painful. Any of those, stop and get assessed.

How it usually goes

Structured exercise training beginning in recumbent positions improves symptoms substantially in a majority of people over three to six months, and it is the intervention with the best evidence. It has to start low and progress slowly, since doing too much early produces a setback and abandonment. Where post-exertional malaise is present - a delayed worsening a day or two after activity - a different approach is needed and progression can cause harm, so that distinction should be established first.

Prevalence basis: Autonomic medicine estimates

Others the same routine covers

These share the Gentle Start (Fatigue & Flare-Ups) routine, so the work is the same. If one of them also sounds like you, that is a reason to expect more from it, not less.

This is general information, not a diagnosis, and it cannot examine you. If it matches you, use it to ask better questions of a clinician rather than to replace one.