PCOS Heart Palpitations: The Causes Worth Ruling Out First

When is a racing heart with PCOS an emergency?

A small set of features separates a genuinely urgent palpitation from an uncomfortable but benign one, and they are worth knowing before anything else in this article, because most causes of palpitations in PCOS are not dangerous.

If none of those apply, the palpitations are almost certainly one of the causes below, and PCOS raises the odds of several of them at once — it is one of the more alarming entries in the wider list of PCOS symptoms worth tracking rather than treating as a one-off.

Why is a racing heart more common with PCOS in the first place?

PCOS is linked to measurably reduced heart rate variability (HRV), a marker of how well the autonomic nervous system balances the “speed up” and “slow down” signals to the heart. A 2024 systematic review and meta-analysis of 17 studies found HRV was significantly lower in women with PCOS than in controls, with the sympathetic-linked LF/HF ratio elevated — in plain terms, the “speed up” side of that balance runs relatively louder in PCOS, which is a physiological reason a heart can feel like it is working harder even at rest. That same meta-analysis found the effect was significant in normal-weight and overweight PCOS but not in obese PCOS, so the mechanism is not simply a byproduct of weight.

Anxiety is the second major driver, and it is both more common in PCOS and a direct cause of the sensation of a racing or pounding heart, often bringing excessive sweating along with the racing sensation, since both are driven by the same adrenaline response. A 2018 meta-analysis of 57 studies and 172,040 women found those with PCOS were 2.75 times more likely to carry a clinical anxiety diagnosis than women without it, and a racing heart is one of the most consistently reported physical symptoms of an anxiety response — the two can run in a loop, where palpitations increase anxiety about the palpitations themselves.

PCOS was renamed polyendocrine metabolic ovarian syndrome (PMOS) in May 2026 by a global consensus of more than 50 medical organisations — same condition, same mechanisms, only the label changed. This article uses PCOS because that is still what most people search.

Why do I feel dizzy along with the palpitations?

Dizziness that arrives together with a racing heart, especially on standing up, points toward the autonomic nervous system rather than the heart muscle itself. Postural orthostatic tachycardia syndrome (POTS) is the clearest example: a JACC review describes it as the most common form of orthostatic intolerance in young people, affecting an estimated 500,000 people in the United States, overwhelmingly young women — a general population figure, not one measured specifically in PCOS, but the demographic overlap with PCOS is substantial and the reduced HRV described above is consistent with the kind of autonomic imbalance that produces POTS. The pattern is a consistently faster heart rate within about ten minutes of standing up, without a matching drop in blood pressure, along with dizziness, lightheadedness, or brain fog that eases again once sitting or lying down. Dizziness without the racing heart has its own, more common set of causes — worth ruling out separately.

Low iron is the second common cause of this exact pairing. A 2025 study of 239 women being evaluated for iron deficiency found palpitations was one of only four symptoms — alongside cold intolerance and easy fatigability — that reliably distinguished those with anaemia from those with low iron but no anaemia yet, meaning palpitations can show up before a standard haemoglobin check would catch a problem. Iron deficiency is disproportionately common in PCOS because heavy, unpredictable bleeding after a long gap without a period is a frequent pattern, and a ferritin check is a reasonable ask even with a normal haemoglobin.

A third, less discussed cause is a post-meal glucose dip. In insulin-resistant PCOS, a large insulin response to a high-carbohydrate meal can occasionally overshoot and pull blood glucose down faster than it should fall, and the adrenaline released to correct that dip produces a fast heart rate, shakiness, and lightheadedness roughly one to three hours after eating — worth noting if your episodes cluster after meals rather than happening at random.

Why does my resting heart rate run high with PCOS?

A higher baseline heart rate, separate from any discrete episode of racing, has direct PCOS-specific evidence behind it. A study of 34 adolescent girls with PCOS found those who were obese had a significantly higher night-time heart rate than obese girls without PCOS, alongside higher 24-hour and daytime blood pressure — changes the authors flagged as an early cardiovascular risk marker rather than a benign quirk. This tracks with the autonomic-imbalance picture above: a resting heart rate that runs a few beats per minute higher than it used to is consistent with the same sympathetic-leaning pattern, not a separate problem needing its own explanation.

Subclinical hypothyroidism is worth ruling out here specifically because it can push in either direction — it more often slows the heart, but the fatigue and weight change it causes are commonly mistaken for anxiety-driven palpitations, and the two conditions are common enough in PCOS to co-occur. A 2025 meta-analysis of 29 studies and 5,765 women with PCOS found 19.7% had subclinical hypothyroidism, with meaningfully higher HOMA-IR and fasting insulin than PCOS without it. A full thyroid work-up is worth doing before assuming a racing or irregular-feeling heart is “just PCOS”, because the treatment for a thyroid cause is completely different from the treatment for an anxiety or iron cause. Untreated obstructive sleep apnoea is a further contributor worth ruling out if palpitations mainly happen at night or on waking — it is more common in PCOS than in the general population and is linked to its own autonomic strain.

What tests actually rule this in or out?

A TSH and free T4 rule the thyroid in or out, a ferritin (not just a haemoglobin) rules low iron in or out even without anaemia, and a fasting glucose and insulin identify whether post-meal dips are plausible. An ECG is worth requesting for any first-time episode, particularly one that felt irregular rather than simply fast, since it is the only item on this list that can catch an actual heart-rhythm abnormality rather than a downstream trigger. A simple lying-then-standing heart rate and blood pressure check, done at home or by a clinician, is the cheapest way to flag whether an autonomic pattern like POTS is plausible before requesting anything more specialised.

Who this reassurance does not cover

Everything above assumes palpitations without the red-flag features named at the start. If you have a known structural heart condition, a prior arrhythmia diagnosis, palpitations that come on specifically with exertion rather than at rest, or a family history of sudden cardiac death, this article’s “probably one of six manageable causes” framing does not apply to you, and a cardiology referral — not a symptom tracker — is the right next step.

Your next step

Log each episode for two weeks: time of day, what you ate or drank beforehand, whether you were standing or lying down, and whether dizziness came with it. That log, plus a TSH, ferritin, and fasting glucose and insulin, will point to one of the causes above in most cases. A racing heart during a broader bad stretch of symptoms is also common enough with PCOS to be worth reading about on its own, if this is showing up alongside everything else feeling worse at once.