Audrey, I do have in general healthy lifestyle. And I do exercise, on regular basis. But I noticed its not a fitness level, its breathing system had to be good. Since on 5 200 m. altitude 51% lack of oxygen. You get to the top with baby steps....Bigger guys with bigger mussels were usually the last ones to come to the top while trekking. I highly recommend this trip. Its awesome. There is two base camps at Everest, one on Nepalese side one on Tibet side. I took higher one. If you not sure about the altitude, and want easier way try Nepalese side. Nepal was amazing..... Food was great in Nepal and Tibet. Its a great challenge in life.