Should an 80yr old woman hypertensive pulmonary artery on oxygen go swimming or get in a hot tub?

Swimming?: Swimming pool is fine and could help increase exercise - caution with hottub as many public ones are too hot and i would probably avoid with those conditions.

That depends: There is nothing inherently wrong with exercise, even in people with severe pulmonary hypertension. Exercise in a pool can be very rewarding because it is easy on the joints. That said, exercise that involves being in a pool, or water, has extra risk for anyone, including those with heart/lung disease and should probably be done with some "supervision" in the form of another adult.