Go for a swim if you're looking for a form of exercise that gets it all done. You'll get yourself a workout that will affect every part of you, with negligible risk for injury. It will work your muscles but is so easy on your joints and is so low impact you'll feel like you're ... swimming.
"Lastly, many people find that they simply don’t have to work as hard to lose weight when they are using swimming as their main form of exercise. You can burn hundreds of calories in an hours time and at the end of the session, chances are you won’t feel as tired or worn out as you would if you had run the entire time. Swimming is easier on the body, even though it requires more physical effort."
Well, maybe you knew all that. But maybe you didn't know that swimming also has a calming effect that lowers blood pressure. Relax while you're working out. What a concept.
http://www.weightladder.com/is-swimming-the-ultimate-exercise