WofPaul, do you read Ben Goldacre? You'd love his Bad Science column in the Guardian. http://www.guardian.co.uk/commentisfree/2006/mar/18/comment.badscience Mind you, even he says that, "Taking a break and doing some exercise is obviously great for improving performance." Wake and Shake may not move children up a NC level, but encouraging daily exercise has got to be good for their long term health. It also improves co-ordination and listening skills. There are probably other benefits that I can't think of off the top of my head. And in our highly pressured results-driven school system, taking ten minutes out to have a bit of fun can only be a good thing.