Norman R Lazarus is a Professor at the Center for Human and Applied Physiological Sciences, King's College London. Current research is into healthy human ageing.' This involves research into physiological systems, skeletal muscle function and architecture, cellular function and the immune system. The major hypothesis driving this research is that physical activity which is part of our evolutionary history is essential for health. Consequently non exercisers have a compromised physiology and while they may not yet be ill, they do show, in physiological tests, reduced values in nearly all physiological indices.Not ill is not healthy. In an era dominated by molecular medicine it is ironic that the major problems facing human health are behavioral. Too much eating and too little exercise.