Why do I shake after anesthesia?
Last updated September 3, 2026.
It is almost always post-operative shivering: common, brief, and not dangerous. The Royal College of Anaesthetists describes shivering after an anesthetic as the body's normal response to feeling cold, with muscles rapidly contracting to produce heat. Anesthesia interferes with the brain's temperature control while cool theatre air, exposed skin, and cold IV fluids lower your body temperature, so you shake as you wake up. It usually passes within the first hour, and recovery staff treat it with warmed blankets and sometimes medication. MedlinePlus lists feeling cold and restless as a normal early after-effect of general anesthesia. The key distinction: post-anesthetic shivering happens while you are awake and aware; it is not a seizure.
What to do
- Tell your nurse straight away: active warming is routine and works fast.
- Do not panic about it: it feels dramatic but is a recognized, harmless side effect.
- Expect it to pass within the first hour as you warm up and the drugs wear off.
- Call your team if shaking returns days later with a fever or wound changes; that pattern suggests infection instead.
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