I have recently been asking myself this question. When is too much? Whilst learning more about physiology and how the body responds to exercise I have been inadvertently using myself as a bit of a guinea pig. Trying to find how my body best responds to exercise, how I can make most gains in my fitness. A few years ago I would have been happy to just complete a marathon, but somewhere along the line the game has changed. This is perfectly normal. It is human nature to p