Anaesthetic causes jetlag

Wellington: Researchers claim to have discovered why people can feel like they have jetlag after surgery – it`s due to the general anaesthetic which alters the activity of genes that control the biological clock.

An international team, led by the University of Auckland, says its findings, published in `Proceedings of the National Academy of Sciences` journal, may have implications for post- operative recovery.

"Our work shows that general anaesthesia effectively shifts you to a different time zone, producing chemically induced jetlag. It provides a scientific explanation for why people wake up from surgery feeling as though very little time has passed," said lead researcher Dr Guy Warman.

The study showed for the first time that general anaesthetic alters the activity of key genes that control the biological clock, shifting them to a different time zone. In fact, the effect persists for at least three days, even in the presence of strong light cues telling the brain the correct time of day, say the researchers.

"It`s been known for some time that after anaesthesia people`s biological clocks are disrupted, and this can compromise their sleep pattern and mood as well as wound healing and immune function. By understanding why this happens we can work out how to treat it and potentially improve post-operative recovery," Dr Warman said.

The work was done using honey bees. "It might sound unusual, but in fact bees are an ideal species to study time perception. Honey bees have an amazingly accurate sense of time, which allows them to forage and find flowers in the right place at the right time of day. By looking at their behaviour we can get a clear idea of what time of day they think it is, and quantify the effects of anaesthesia. An added advantage is that their biological clocks work in a very similar way to mammals," he said.