Fatigue, constantly aching muscles
Restless sleep and insomnia
Frontal knee pain
Increased risk of colds
The solution is - only do high impact activity (circuits, weights, hard running) on alternate days
- increase the amount gradually
- always give your body time to rest
It would be glib to say I experience nothing of the above, simply because most of what I do isn't hard enough. Sadly I do experience many of these exercise-related problems but not because of exercise, so I totally agree with the solutions. In fact I adopt the assumption that I'm constantly work in progress, as if I am returning from holiday or injury. I never get disappointed about my personal best.