Paramedics urge Londoners to learn CPR before winter cardiac arrest surge

London Ambulance Service is urging more people to learn CPR and how to use a defibrillator after figures showed cardiac arrests rise sharply during the colder months.

Crews attended 3,400 cardiac arrests in winter 2025/26, which was 488 more than during the previous summer and represented a 17% increase. The preceding winter recorded 3,643 incidents, 23% more than in summer 2024.

Taken across both years, London experienced approximately 20% more cardiac arrests during winter than summer. Colder temperatures can place additional strain on the heart, particularly for people already living with cardiovascular conditions.

Fewer than one in 10 people survive an out-of-hospital cardiac arrest in the UK, making immediate help from witnesses critical. Anyone who finds somebody unresponsive and not breathing normally should call 999, begin chest compressions and use a public-access defibrillator if one is available.

The ambulance service issued its appeal alongside Restart a Heart Day, an annual campaign helping members of the public gain the confidence to respond. CPR and early defibrillation can substantially increase a person’s chance of surviving while an ambulance is on its way.

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