Shock and Fainting: What to Do

Hypovolaemic shock means the body's tissues are not getting enough oxygen, often after blood loss or a burn. It is life-threatening: lie the casualty down, raise their legs, call 999. Fainting is briefer, but treat it seriously if they do not recover within a minute or two.

How the circulation works

The heart is a muscular pump the size of your fist, sat centre-chest and slightly left. One side sends oxygen-rich blood out to the body's tissues; the other receives it back and sends it to the lungs to collect more oxygen. Arteries carry blood away from the heart, veins bring it back, and capillaries link the two at the tissues.

Blood itself is plasma (mostly water), platelets that clot, red cells that carry oxygen, and white cells that fight infection. Shock is what happens when this transport system fails.

Recognising hypovolaemic shock

Causes include blood loss, burns, low blood pressure, spinal injury and poisoning.

Pale, cold, clammy skin as blood is pulled away from the extremities to protect vital organs
Rapid but weak pulse
Rapid, shallow breathing
Feeling thirsty and light-headed

Treating shock

1
Treat the cause if you can.
Control the bleed, cool the burn.
2
Call 999.
Shock is life-threatening. Do not wait to see if they improve.
3
Lie them down and raise their legs slightly above heart level.
Keep them calm and reassured.
4
Be ready to start basic life support.
If they stop breathing normally, start CPR.

Fainting

A faint is a sudden, usually brief loss of responsiveness caused by a lack of oxygen to the brain.

1
Feeling faint? Help them to the floor and raise their legs.
Blood returns to the brain and most people improve quickly.
2
Ask questions while they recover.
Dehydrated or skipped meals? A drink and something sugary helps, then something more substantial once they can sit up. No obvious cause? Advise them to see their GP.
3
A full faint that does not improve in 1 to 2 minutes is not a faint.
Check breathing. Not breathing: start CPR. Breathing: recovery position, then call 999.

Lie them down early, before they fall down
Raise the legs above heart level
Call 999 at the first sign of shock

Don't

Do not give a casualty in shock anything to eat or drink
Do not leave them alone
Do not assume a faint is over just because their eyes open

Common questions

What are the signs of shock?

Pale, cold and clammy skin, a rapid but weak pulse, fast shallow breathing, thirst and light-headedness. Treat the cause, lie them down, raise the legs and call 999.

What is the difference between shock and fainting?

A faint is a brief drop in oxygen to the brain that usually corrects within a minute or two once the casualty lies down with legs raised. Shock is a failing circulation, it does not fix itself, and it needs an ambulance.

Go beyond reading

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First Aid Guru guides support learning and refreshing your knowledge. They are not a substitute for regulated, hands-on first aid training or for professional medical advice. In an emergency call 999 (UK) and follow the call handler's instructions.