Water aerobics is a great way to condition and get your heart pumping without all the stress and strain of a work-out on land.  Grab a friend and make up your own fun routine or participate in a local “Y” or gym program.  There are different levels of difficulty available.  Some classes are deep water only and others keep you in the shallow end.  Other than a bathing suit and towel, not much else is needed besides the pool for this type of exercise.