Is jetlag worse going east or west?
Monday 21 July, 2008 | Ask the Expert: Dr Warren K Harrex
Q: I HAVE heard that flying east causes worse jetlag than flying west. Also, apparently there is a jetlag difference depending on whether you fly from the east coast of Australia or from the west, say Perth. Is this true and if so, why?
Our expert is Dr Warren K Harrex, president of the Australasian Society of Aerospace Medicine.
A: Flying east tends to cause more jetlag than flying west, so flying from, say, Australia to USA is often worse than Australia to Europe.
Returning from Europe to Australia is often worse than returning from USA to Australia.
Why?
The body’s natural circadian rhythm is usually about one hour longer than a normal 24 hour day. It is about 25 hours. We adapt to time zone changes at about one hour a day. So travelling east or west to a time zone change of 10 hours would theoretically normally take about 10 days to fully adapt.
As our natural circadian rhythm is 25 hours, we can adapt more quickly to travelling west, so we may recover more quickly – perhaps in five or six days.
It is also harder to adapt when the days appear shorter, as when travelling east.
As far as leaving from Perth vs East coast is concerned, there is about a three hour time zone difference. So travelling west to Europe from Perth would result in less time zone change than travelling from Sydney. Conversely, travelling to the USA from Perth would result in a greater time zone change than travelling from the east coast of Australia to the USA.
So, should you have the luxury of choice, if travelling west, start the journey in the west. If travelling east, start in the east.
