I think if you ask your family doctor to weigh to how many watts and pulse Do you can you're on the "safe side".
My doctor recommended me 70 watts and a maximum of a pulse of the 100th If I think also not sooo Doll, but is important at all to do something for yourself and your body!
In this sense, stay in good health and have fun.
If you do it at a rate that is not to ambioniert I think that is fine. I mean to say that you should not try to provide this route in a record time. Let it slow and eighth constantly your pulse.
Advantageous it would be to reduce your weight with certainty, the joints would then be less burdened.
You have to paying attention to your pulse itself. It would be best even if someone could help you if you what happens!