High Intensity Interval Training (HIIT) burns 9 times higher than conventional exercise. It stimulates body to convert fat store into energy effectively. For beginners: warm up, start 30 seconds intensive phase, follow by 90 seconds rest. Repeat 6-8 times. It takes 15-20 minutes. HIIT can be applied during cycling, running, and rope skipping, and so on. For obese or older adults, it is best to do it with the monitoring of professionals to avoid overloading yourself. Not enough time for exercise? It is not a valid excuse anymore!