I was dizzy when initially using it but it subsided quickly and hasn't come back subsequent times. I've only used it 3 times so far but I am already down 2 pounds after being in a plateau for a month, so it's promising but early. I've had success with standing on it and sitting on it, but if I try to push up or plank on it, it vibrates my head too much and I feel like I'm going to get a concussion.