10. Free

It is free! Unlike most other forms of exercise, all walking requires is a pair of good walking shoes. Walk in the park; on the road; up the stairs; on a treadmill; in a long corridor, it really doesn't matter. You don't need expensive equipment or a partner to do this. So if you're in the mood for a good, safe workout, just start walking!

Source: www.mdhil.com

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