It depends on an individual's fitness levels etc really. I find I get chest pains if I do too much so I only do moderate walking for now.. the dr says i have costochondritis. I don't think I would personally manage an hour! I think cycling, walking and swimming are good. Make sure not to over exert yourself, especially if you don't sleep too well as this can put added pressure on the heart. Get plenty of rest in between the exercise and also don't take too much water, keep hydrated but watch as too much you can actually get hyponatremia and it can also water down your nutrients. I'm not saying don't drink, just don't have way too much! And eat plenty green veggies