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Volunteer responder systems
Denmark, Sweden and Norway alert trained volunteers by phone to arrests near them — one to fetch the defibrillator, one to start compressions. How the systems work, who can join, and what happens when your phone goes off.
CPR in sixty seconds
- Unresponsive and not breathing normally? Gasping is not breathing. Treat it as a cardiac arrest.
- Call 112 (113 in Norway). Speaker on, phone on the floor. Stay on the line — the dispatcher will coach you.
- Push hard and fast in the centre of the chest: 5–6 cm in an adult, 100–120 per minute, letting the chest come all the way back up.
- Send somebody else for a defibrillator. Do not go yourself unless it is seconds away. Keep compressing.
- Turn the device on and do what it says. It decides whether to shock. After a shock, go straight back to compressions.
This is a reference written for bystanders, not a diagnosis, a training course or medical advice. It cannot tell you what is wrong with a particular person, and it does not replace the dispatcher on the other end of an emergency call — they can see what is near you and they will talk you through it. If you are worried about your own heart, or about a symptom, that is a conversation with a clinician rather than a page on a website.
The idea
An ambulance cannot be everywhere, but somebody is always closer. Volunteer responder systems keep a register of people who have agreed to be alerted, know their approximate position from their phone, and when a suspected cardiac arrest is reported nearby, send them an alert with the address. The standard pattern is to dispatch at least two: one straight to the patient to start compressions, one via the nearest registered defibrillator. The volunteer arrives before the ambulance in a large share of activations, which is the entire point.
Denmark: the largest of its kind
The TrygFonden Hjerteløber scheme, run by the TrygFonden foundation with the Danish regions, is the biggest volunteer responder network in the world by participation. The associated Hjertestarter-Netværket holds over 26,000 registered defibrillators and the responder scheme has over 55,000 active volunteers, on the operator's own published figures. Anyone over eighteen who is willing can sign up, and the alert arrives as a push notification with a map, an address and the option to decline.
Sweden and Norway
Sweden's SMSlivräddare system grew out of Karolinska research on text-message dispatch of lay responders and operates through regional emergency services in cooperation with SOS Alarm; volunteers are alerted to suspected arrests within a short radius and directed either to the patient or to a registered device. Norway runs alerting of registered lay responders through its emergency medical communication centres alongside the national defibrillator register held by NAKOS. In all three countries participation is voluntary, unpaid and declinable — you are never obliged to accept an alert.
Estonia, Latvia, Lithuania and Finland
The Baltic countries do not currently operate a general public volunteer-responder scheme on the Danish or Swedish model; the first responder in practice is a bystander, a police or rescue unit, or in some municipalities a first-response vehicle. Finland has no single nationwide lay-responder alerting scheme either, but the defi.fi register feeds device locations to the emergency services' 112 Suomi app so that a caller or a dispatcher can find the nearest device. Where no scheme exists, the dispatcher on the phone is the volunteer responder system, and they are good at it.
What to expect if you sign up
Alerts are infrequent for most volunteers and arrive at inconvenient moments by definition. You can decline any alert, and you should decline when you are driving, drunk, with small children or too far away to be useful. Systems provide a debrief afterwards, and taking it up is worth doing: attending a cardiac arrest as a lay responder is a heavy experience whether or not it goes well, and the aftercare exists for a reason.
Sources: TrygFonden Hjertestart og Hjerteløber · hjertestarter.dk · SMSlivräddare (Sweden) · SOS Alarm (Sweden) · NAKOS (Norway) · Sydänliitto on the defi.fi service · checked 2026-09-08
Frequently asked questions
Do I need medical training to be a volunteer responder?
Not usually a professional qualification. The schemes ask for a willingness to do chest compressions and to use a defibrillator, and most provide or require a short course. Requirements differ by country and region.
Can I ignore an alert?
Yes, always. Declining is a normal part of the system, and you should decline when you are driving, unable to attend or too far away. Response rates are built on the assumption that many alerts are declined.
Do these systems exist in the Baltic countries?
Not as general public schemes at present. The dispatcher-guided call is the equivalent, and it is effective — stay on the line, put the phone on speaker and follow the coaching.
How the system around it works
The chain of survival, link by link
Recognition and a call, early CPR, early defibrillation, advanced care and recovery. What each link is actually worth, which one the public owns, and where the chain breaks in practice.
What the survival numbers actually say
Roughly one in ten survives an out-of-hospital cardiac arrest, and the spread between towns is wider than the spread between treatments. How to read the statistics without being misled by them.
National registers, and getting your device into one
A defibrillator the dispatcher cannot see barely exists. What a national register is, which one is the real one in each country, why registration is free, and the paid look-alikes to avoid.
Where public defibrillators actually are
The green sign with the heart and the lightning bolt, the places that reliably have one, the cabinets that are locked and the ones that are not, and what to do when you have thirty seconds to decide whether to go looking.
What a defibrillator costs to buy and to keep
The purchase is the small part. Pads and batteries expire on a schedule, cabinets and signage cost real money in a cold climate, and the recurring line is what an organisation forgets to budget for.
Everything on this subject
Before the emergency, there is a long quiet stretch
Blood pressure, resting heart rate, movement and sleep are the part of this you can act on for years beforehand. TempoLife keeps them in one place, free to start.