Risks and side effects – shivering

About this leaflet

This leaflet is about shivering after an anaesthetic. This is a side effect that you might experience if you have a general or regional anaesthetic. It explains the causes of shivering and what can be done about it. 

You can read about different types of anaesthetics in our Patient information leaflets and video resources section.

What is shivering?

• Shivering is the body’s natural response to feeling cold. To keep warm the muscles in the body contract and relax quickly, causing shivering.
• Shivering after an operation can be uncomfortable, but is not dangerous and usually stops within 20–30 minutes.
• Shivering causes your body to require more oxygen. You might need additional oxygen through a mask.

How likely is it to happen?

These numbers come from research studies. You can find out about the research we used in our Anaesthesia and risk evidence table.

What causes shivering after an anaesthetic?

• Operating theatres can be cold. During surgery parts of your body will be exposed to cold air and your temperature can drop.
• Sometimes the anaesthetic medicines and gases affect the signals in the body that control your temperature.
• Shivering can happen after a general anaesthetic, but also after regional anaesthetics (epidural or spinal).

What can the healthcare team do?

A nurse will always be with you in the recovery room after the operation. They will check your temperature and give you warm blankets or a hot drink.

If this doesn’t help, the team might give you either medicines to warm you up or warm fluids through a vein. 

What can I do myself?

Try to stay as warm as possible while you are waiting to go to the operating theatre. If you are warm before the operation, you are less likely to feel cold afterwards.

Tell the nurses if you are cold and they can give you blankets. 

You could bring warm clothing and slippers to hospital from home.

Good to know

If you have had shivering after an anaesthetic, it does not mean that you are more likely to experience it again if you have another anaesthetic in the future.

This leaflet has been produced by Leila Finikarides for the RCoA, in collaboration with patients, anaesthetists and patient representatives of the RCoA.

Disclaimer

We try very hard to keep the information in this leaflet accurate and up-to-date, but we cannot guarantee this. We don’t expect this general information to cover all the questions you might have or to deal with everything that might be important to you. You should discuss your choices and any worries you have with your medical team, using this leaflet as a guide. This leaflet on its own should not be treated as advice. It cannot be used for any commercial or business purpose. For full details, please click here.

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Sixth Edition, November 2024
This leaflet will be reviewed within three years of the date of publication.

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