There are several- it depends on what part of the city you are staying in. There is a Gold's Gym and one other (can't remember the name) in the hotel zone and another one in the San Fransican Hotel (Los Meurtos area). Gold's has it all (of course) and the San Fransican is quite basic but quiet and available 24 hrs if you buy a week or longer membership. Google gyms in PV and see what you can find. It's been 2 years since I've used a gym in PV so there could be more by this time. I'd be interested in knowing what you find and your experience (for my next trip).