This brings up an interesting point. How much running of training of any kind is too much? Yes of course, some training is good, coz if it is done correctly then it will improve one's level of condition and health. But if it is not done correctly, or even worse if it is overdone, it won't lead to an improved level of health, looks, and/or condition. Dr. Ken Cooper of The Aerobic Institute in Dallas used to say "Train, train, and train even more" or something to this effect. But a few years back he recanted this statement and said something like this, "Anyone who trains for more than 1 hour weekly isn't training for health and fitness purposes"