One thing I have not yet discussed (maybe because it's winter!) is the great benefit of moving in the water. Swimming is fantastic exercise! Don't limit yourself to just swimming laps, however.
Walking takes a lot of coordination - that is moving lots of systems together and in sync with each other. Jumping takes even more. Walking in the water requires a lower level of coordination AND provides some buoyancy. Ditto for jumping! Even when I am unable to jump on land, if I get into waist or chest level water, I can jump. If I tip, I just float! No impact, no loss!
Using the water as a general exercise medium works for aerobic-type exercise, yoga, and some cardio (water running or swimming). There are special flotation belts that keep the body upright in water and allow you to sort of run in place in deep water. Check out AquaJogger, for one.
Additionally, when the impact factor is removed AND the body temperature remains lower, the chances of being able to achieve an excellent workout increase. Even if I am limited on land, I generally and much less restricted in the water.
So, get to a pool or an ocean. Join a water exercise class or go it alone. Try noodles, life jackets, running belts, swimming, jumping, yoga poses (you may be surprised what you can do)...