Science Questions

How do full spectrum bulbs prevent seasonal affective disorder? Colin Donnelly

We put this question to Professor Russell Foster:

Russell - If the light is bright enough it actually doesn’t matter too much which wavelength it is.  When we say these receptors are most sensitive to blue light that’s the wavelength if you were to lower the light levels it would then be blue that is effective.  If you’re using a full spectrum lamp that’s bright enough it will be perfectly good.

Chris - So this is where people would perch themselves in front of a bright lamp in the morning?

Russell - That’s right, yes.

Chris - And this works, does it?

Russell - Remarkably enough it works.  Now we’re beginning to understand the mechanisms behind it.

July 2008