Having had two surgeries under general anaesthesia recently, I have been wondering... Being under general anaesthesia is physiologically not the same as sleeping. Sleep is needed in humans for restorative processes, a rule of thumb being 6 to 8 hours a day.

However, not all surgeries are like mine and only take one or two hours. Extreme cases, such as separating conjoined twins or complicated brain surgery may take a lot longer, even up to several days.

During and after long surgeries, is the lack of sleep a problem for the patient? How is it managed if this is (or would be) a problem?

  • Very interesting question that leads onto other questions that I'd like to ask.
    – Dave Liu
    Commented Nov 22, 2015 at 23:44
  • Interesting but "Anaesthesia and sleep" is not a question. Can you rephrase the title into a question?
    – Bob Ortiz
    Commented Dec 6, 2019 at 11:18

1 Answer 1


You're right that sleep and general anesthesia are very different, and general anesthesia in fact actively inhibits the glymphatic circulation that clears waste products from the brain). Since most of are able to pull an all-nighter and except for problems with memory, focus etc, be OK after a couple of days' catch-up sleep, the sleep deprivation isn't an acute issue -- after all, folks after major surgery tend to sleep a lot anyway, as the body needs extra sleep during healing.

As far as preventives, there is an ongoing study to see whether pre-operative cognitive training can reduce the odds of post-operative delirium, one of the ways in which temporary post-surgical cognitive dysfunction can be visible.

More seriously, there may be long-term costs of surgery, with or without anesthesia, on cognitive reserve. This is well-known for cardiac surgeries, but may also be true for any surgeries, as a cross-sectional study found that even the lifetime number of non-cardiac surgeries one's had, correlates with reduced verbal learning and memory in one study of healthy older adults.

The general issue, called Post-Operative Cognitive Dysfunction (POCD) is an active area of investigation for older adult care. There seem to be multiple suspects - from inflammation to brain hypo-perfusion -- and each will suggest steps that can reduce the risk. A recent review is Current Perspectives on Postoperative Cognitive Dysfunction in the Ageing Population.

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