I had a similar overconfidence situation during our move. I had been in an animal car (a friend regularly transports her two cats to her cottage in said car) for around 2.5 hours but thought that I'd be fine carrying heavy items up and down stairs a few days later. Nope. Residual lung stress from the animal plus the dust and exertion made for a very unpleasant afternoon because I'd left my inhaler in my purse at the other house :(

Hopefully there can be some way of accommodating your needs at the studio. I feel you on the wanting to get into shape. I've just started walking to work from the new house, and our corporate gym memberships kick back in once October starts so I've got my fingers crossed for a more fit autumn.