The participants ate a specific diet, then taken to a hospital room where researchers were able to control the air intake ang determine the oxygen, carbon dioxide and water content of the air. Through these indices researchers were able to measure how many calories the volunteers burned. While each person lived inthe room, they were kept on their strict diet and could only watch TV or use a computer. However, on one day they were asked to participate in HIT on a gym bike, pedalling as fast as ther could for five 30-second periods with four-minute recovery periods between. The results were startling: the volunteers burned an average of an extra 200 calories on the workout day in sprite of doing high-intensity activity for just 2.5 minutes. Other experiments have revealed individuals into two groups. The first group trained five days a week over six week, taking an hour of moderate-intensity exercise per day, totally five hours per week. The oxygen intake of this group improved by an average of 9%. The second group's training sessions were eight 20-second intense workouts followed by ten seconds of rest. Their oxygen intake improved by 15%