Exercise classes in Rio? (Rio de Janeiro)

Hello Everyone,
I'm going to be in Rio for the entire month of January and am looking for a way to get a good workout while I'm there. I was wondering if anyone could recommend any foreigner-friendly exercise classes? Possibly samba or capoeira, to get a bit of a cultural experience as well? But I'm open to other suggestions as well.
Thanks in advance for any advice you can give!
Carissa