I've had several. When I was in good shape, they put the treadmill at a high speed until my heart rate got high enough, but when I was in less physical condition we just walked. No problem with it, they monitor you and never give you more than you can take. Nothing to worry about. I had one time where they just walked me up and down the hall. The person holding the BP monitor had a hard time keeping up with me and I had a hard time getting my HR up high enough.