These are difficult intervals (some of the toughest) so come into the workout motivated and ready to suffer. The payoff is that you will be a more powerful, faster bike rider. Imagine you are the one racing up the Mur de Huy with the taste of blood in your mouth and the podium is within your grasp! If you have snot coming out of your nose, or drool coming out of your mouth at the end of the last few intervals you are doing them correctly. For the goal-oriented athlete, there can be a tremendous amount of satisfaction in the successful completion of such a difficult workout within the prescribed zone 5 wattages.