Science Questions

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

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? Nassar Husari

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.

July 2008