Thanks for the reply. Very helpful.
Indeed, the people of Alfama seem to keep fit by walking up and down all the winding stairs in the area. There isnโt a single gym.
I checked out Envy. Yes, it is beautiful. Yes, it is pricey (65 euros per month - and only with a 3 month+ contract). Yes, it is cramped and has an awkward layout. I felt uncomfortable there. It felt cramped, and even with only 4 people in the weight room. It also felt quite pretentious.
The Fitness Huts arenโt near Alfama, although they look great. Instead, I found a place called โginasio fabrica do fisico.โ It is a 13 minute bus ride from my flat in the Alfama (I have a monthly public transit pass, which costs 35 euros per month). The gym costs 29 euros per month and there is no contract. The gym is huge, uncrowded, and clean but not pretentious.
If you are staying for a few days in the cityโs old center, Envy is a great option to treat yourself. For a longer stay, I highly recommend Ginasio Fabrica do Fisico.