High Intensity Interval Training (HIIT) or High Intensity Training, as it is often termed, is said to be quite useful in increasing VO2 max in well trained athletes. Some studies suggest that including training bouts that are performed at 95 to 100% VO2 max can improve the VO2 max of elite athletes. Therefore, it can be concluded that HIIT can be useful for improvement of VO2 max even in advanced level athletes that want to optimize performance.