Atrial fibrillation

Also called: AF; irregular heartbeat

Exercise strongly helps Strength

An irregular, often fast heartbeat that raises stroke risk substantially. Most of what drives it - high blood pressure, excess weight, sleep apnoea and alcohol - is exactly what exercise and lifestyle change address, and aggressive risk factor management genuinely reduces the burden.

How common: Around 2% of adults and 9% of over-65s; rising steadily

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What it is

In atrial fibrillation the upper chambers of the heart quiver rather than contracting properly, producing an irregular pulse and allowing blood to pool - which is why the stroke risk rises and why anticoagulation is central to treatment.

The important shift in understanding over the last decade is that AF is largely a consequence of things that remodel the atria over years: high blood pressure, obesity, sleep apnoea, alcohol and inactivity. Trials of aggressive risk factor management show substantial reductions in AF burden and better outcomes from procedures, which makes lifestyle a treatment rather than an adjunct.

What it feels like

Palpitations - a fluttering, racing or thumping irregular heartbeat
Breathlessness and fatigue on exertion
Light-headedness and reduced exercise tolerance
Sometimes no symptoms at all, and found on a routine check
Episodes that come and go, or a permanently irregular pulse

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.

High blood pressure: The single largest population-level contributor. Raised pressure stretches and remodels the left atrium over years, creating the substrate on which AF develops.
Obesity: Strongly and independently associated, through atrial stretch, inflammation and fatty infiltration of the atrial tissue. Weight loss of around ten per cent substantially reduces AF burden in trials.
Obstructive sleep apnoea: A major and frequently missed driver. Repeated overnight oxygen drops and pressure swings remodel the atria, and untreated apnoea substantially reduces the success of ablation.
Alcohol: Dose-related and one of the clearest triggers - the association with binge drinking is old enough to have its own name. Reducing alcohol reduces recurrence measurably.
Age: Prevalence rises steeply with age as atrial tissue changes. It is the most common sustained arrhythmia and largely a condition of later life.
Extreme endurance exercise: An unusual U-shaped relationship: moderate exercise reduces risk, while decades of very high-volume endurance training raises it, probably through atrial stretch. This applies to marathon and ultra volumes, not to ordinary training.
Thyroid overactivity: An overactive thyroid is a classic and reversible cause, and it is standard to check thyroid function in new AF.
Heart disease of any kind: Valve disease, heart failure and previous heart attack all remodel the atria and predispose to AF.
Diabetes: Independently associated, through similar remodelling and inflammatory pathways.
Inactivity: Sedentary behaviour raises risk, and moderate regular exercise reduces both incidence and symptom burden in people who already have it.

Who tends to get it

Adults over sixty-five, in whom prevalence rises steeply
Anyone with high blood pressure, obesity or diabetes
People with sleep apnoea, treated or otherwise
Regular drinkers above modest amounts
Lifelong very high volume endurance athletes

What makes it worse, and what settles it

Makes it worse

Alcohol, which is one of the most reliable individual triggers
Untreated sleep apnoea, which drives recurrence and undermines treatment
Uncontrolled blood pressure
Weight gain
Stopping anticoagulation without medical advice, which is the decision that carries stroke risk

Settles it

Moderate regular exercise, which reduces symptom burden and improves quality of life
Weight loss of around ten per cent where relevant, which reduces AF burden substantially in trials
Treating sleep apnoea, which improves outcomes from every other treatment
Reducing or stopping alcohol
Controlling blood pressure and diabetes, which is treating the substrate rather than the rhythm

What actually helps

The short version: Atrial remodeling driven by hypertension, obesity, sleep apnea and alcohol - most of which exercise addresses

Strength work: Full Body; moderate resistance training; Legs: Quads

Stretching: Secondary

Massage: Secondary

Also worth doing: Aerobic training; weight loss; treating sleep apnea; reducing alcohol - the LEGACY and CARDIO-FIT studies show risk factor management reduces AF burden

What the evidence says: Moderate exercise plus weight loss substantially reduces AF burden and recurrence. The dose-response is U-shaped - extreme endurance volume increases risk, so do not frame more as better.

The names above are the Targets qFIT tracks — the Muscle Guide explains what each one does, and Quick Add switches on the Exercises you already have.

No ready-made routine for this one yet

249 of the 267 problems here have a routine already built, and this is not one of them — usually because the work that helps is covered by a general routine rather than needing its own. What actually helps above names the muscles and the work involved, which is enough to put it together yourself.

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Get it checked if…

Palpitations with chest pain, fainting or severe breathlessness - urgent. Very high-volume endurance exercise paradoxically increases AF risk in athletes

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

Aggressive risk factor management - weight, blood pressure, alcohol, sleep apnoea, exercise - reduces AF burden meaningfully over six to twelve months and improves the success of ablation and medication. Exercise is safe and beneficial in AF, though effort should be built gradually and with medical advice where rate control is an issue. Anticoagulation decisions belong entirely with the medical team: the stroke risk is the reason AF is treated seriously, and it does not go away because the rhythm feels better.

Prevalence basis: Cardiology registries

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.

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