I am sure this will bring many contradicting opinions, but I remember reading that swimming is not as conducive to weightloss as one might think. True, it expends alot of energy but for the body to be bouyant it needs fat. Therefore the body is not so eager to give it up as it would be on the other exercise suggestions. IMO walking the dog might be all that you need. What is important is to do something consistantly.

Black57