High intensity intervals are essential when the racing season is just around the corner or if you want to improve your performance. The better trained you are the more relevant they become. As people have to do HITs quite demanding it is recommended that with such intensity people do 2 sessions weekly. It is normal to see a trend of ramping up the intensity of intervals as a race season approaches. That said, it is equally important to integrate specific training that is relevant for the event being trained for, along with the HIT.