Science Questions

Will a red light on the back of the knee prevent jetlag?

Sun, 6th Jul 2008

Listen Now    Download as mp3 from the show Body Clocks and Circadian Rhythms


Nassar Husari asked:

I once heard that in order to avoid jetlag when travelling you should shine a red light on the back of your knees. Is this true?



We put this question to Professor Russell Foster:

Let’s kill this one dead!  In ’98 a group of researchers at Cornell University suggested that red light behind the knee would train the body clock.  This got huge amounts of publicity.  A lot of us thought it was nonsense at the time.  It was published in Science, incidentally.  Five studies around the world tried to replicate the findings and all completely failed.  It looks as though there was some artefact in the experimental design of that original paper which was fundamentally flawed and they got it badly wrong.  It did cause a huge amount of commotion.  Let me assure you, it is nonsense.


Subscribe Free

Related Content


Make a comment

nassar asked the Naked Scientists:

I once heard that in order to avoid jet lag when travelling, one should shine a red light (say from a torch) into the back of the knee. What is the validity of this statement.

Thanks.... and an excellent show

What do you think? nassar hazari, Sat, 5th Jul 2008

I've never heard of that & I don't see how it could help. DoctorBeaver, Sat, 5th Jul 2008

I am surprised that the Japanese have not invented a portable ' back-of-knee-red-light-shiner '

It's all quite obvious really.

Jet lag fairies live in your blood stream....they commute back and forth every day and of course obey the highway code !.....The shining of a red light in the back of the knees acts like a traffic light.......when you disembark the plane.....flick the light to green momentarily and this will start the Jet Lag Fairies back on their usual path and acclimatised already to the new time zone.

This is true.

neilep, Sun, 6th Jul 2008

I'm convinced. DoctorBeaver, Sun, 6th Jul 2008 RD, Sun, 6th Jul 2008

I hope my words taste good coz I'm about to eat them! DoctorBeaver, Sun, 6th Jul 2008

So, there we have it. Debunked on the radio show!  DoctorBeaver, Sun, 6th Jul 2008

A recent paper on this matter...

RD, Sun, 27th Jul 2008

Weird! The last thing I read about cryptochromes (New Scientist) was about their role in sensing magnetic fields (by fruitflies) for navigation. Does that mean that we havew a built in compass too? Bored chemist, Sun, 27th Jul 2008

See the whole discussion | Make a comment

Not working please enable javascript
Powered by UKfast
Genetics Society