The Three Eyes

High intensity interval training is when you go very, very hard for a brief period of time and then take a short break. Studies have found that it can improve your fitness and also improve your health just as much as much longer bout. The first eye intensity hereis gretchen reynolds again. And if you do ten of those intervals, you get essentially the same physiology al changes within your body as if you do about 90 minutes, or two hours,. Even in more common endurance training, where you just go ride, e.g., cycling.