Regular exercise is a vital part of a healthy lifestyle, but is there such a thing as over-exercising? You bet -- and according to Sarah Brown, fitness expert for ThatsFit.ca, it's more common than you think. What's more, it can be harmful to your health.

If you think you might be guilty of over-exercising, ask yourself a few important questions. Do you seem to spend most of your free time at the gym? Have your sleep patterns changed? Do you seem to be more susceptible to illness than others? Do you suffer from more aches and pains than usual? If the answers to most of these are a yes, it could be your body's way of telling you to slow down.

Instead of working out more, work out better with tips from this celeb trainer.