Why young athletes get hurt

The UK charity Cardiac Risk in the Young (CRY) works to raise awareness that young people can die suddenly from undiagnosed heart conditions and supports cardiac screening for people aged 14 to 35. The NHS describes cardiomyopathy as a disease of the heart muscle that can run in families and may cause no symptoms. Exercise does not cause these conditions, but intense exertion can trigger a dangerous heart rhythm in someone who has one. Most young athletes will never face this, which is why knowing the warning signs matters.

01Undiagnosed heart muscle disease

Inherited conditions such as hypertrophic cardiomyopathy thicken or weaken the heart muscle. They may cause chest pain, breathlessness or fainting with exercise, or no symptoms at all until a cardiac arrest.

What helps

  • Never ignore fainting or near-fainting during or just after exercise; get a medical assessment before training again.
  • Report chest pain, unusual breathlessness or palpitations during exercise.
  • Tell your doctor about any family member who died suddenly or unexpectedly under 35.
  • Consider cardiac screening where it is available and recommended for your sport or age.

02Electrical rhythm disorders

Conditions affecting the heart's electrical system can cause sudden, dangerous rhythms. An ECG can detect many of them. Screening programmes for young people use an ECG and a questionnaire.

What helps

  • Know your family history and share it with your doctor or team medic.
  • Avoid training with a fever or viral illness; heart inflammation can follow infections.
  • Do not use stimulants or performance drugs, which strain the heart.
  • Follow medical advice if a screening test shows an abnormality.

03Not being ready to respond

Survival from sudden cardiac arrest depends on immediate CPR and early defibrillation. The NHS CPR guidance explains that hands-only CPR and an automated external defibrillator (AED) can keep someone alive until help arrives.

What helps

  • Learn CPR and how to use an AED; refresh every year or two.
  • Make sure clubs, schools and venues have an accessible AED and a plan.
  • If someone collapses and is not breathing normally, call emergency services, start CPR and send for the AED.
  • AEDs give spoken instructions; anyone can use one.

Weekly checklist for young athletes

  • Check where the nearest defibrillator is at every venue.
  • Ask family members about any sudden deaths under 35.
  • Rest from hard training when you have a fever or viral illness.
  • Report any fainting, chest pain or palpitations with exercise.
  • Keep CPR training current.
  • Make sure coaches know the club's emergency plan.

When to see a professional

  • Fainting or near-fainting during or right after exercise.
  • Chest pain, unusual breathlessness or palpitations with exertion.
  • A family history of sudden death under 35, cardiomyopathy or inherited heart rhythm problems.
  • An abnormal result on a screening ECG.

If someone collapses and is unresponsive and not breathing normally, call emergency services, start chest compressions immediately and use a defibrillator as soon as one arrives.

Where ONU fits

ONU brings your activity, sleep and recovery trends together. It is not a heart screening tool and cannot detect cardiomyopathy or rhythm disorders. A normal trend in the app does not rule out a heart condition; symptoms always need a medical assessment.

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Common questions

How common is sudden cardiac death in young athletes?

It is rare, but it is devastating when it happens, and many cases are linked to heart conditions that could have been detected. Knowing the warning signs and family history is important.

Should every young athlete have an ECG?

Policies differ between countries and sports. Organisations such as CRY offer screening for young people aged 14 to 35. Discuss with a doctor, especially if there are symptoms or a family history.

Can I hurt someone by using a defibrillator?

AEDs analyse the heart rhythm and only advise a shock if it is needed. They give spoken instructions, and using one quickly greatly improves the chance of survival.

Sources and further reading

Educational information drawn from the public-health sources listed on this page. It is not a diagnosis, a treatment plan or a guarantee that you will avoid an illness or injury. ONU does not diagnose, treat or prevent disease. Speak to a qualified professional about anything that concerns you, and follow the rules of your employer, sport or local health service.