Yes! The infrared heat sets off a chain reaction within the body. As your body's cooling mechanism (i.e. perspiration) kicks into gear, your heart rate will increase, which increases your metabolic rate, causing your body to burn calories.
It's estimated that you will burn up to 700 calories during a one hour session at 80°C.
Lying in the Rejoover is like working out, without working out. Yes, you'll even get that euphoric post-workout high!