Sprint Snacks: The Effects of Prolonged Rest on Reduced Exertion Interval Training.

An adapted sprint interval training protocol involving 2-3 repeated 20-second sprints separated by 2-3 minutes rest (termed reduced exertion high- intensity interval training (REHIIT)) has been developed and has been shown to promote fitness benefits. This data shows how little exercise one may need to improve cardiorespiratory fitness, provided they are willing to work very hard. However, it is unknown whether the benefits of REHIIT are because of the "all-out" nature of the sprint efforts themselves or the pattern of completing sprints with relatively short (i.e., minutes) rest periods within a workout session. We are inquiring whether performing the same number and style of sprints with prolonged rest (i.e., 1-4 hours of rest in between sprints) is equally effective for improving aerobic fitness when compared to more traditional sprint interval training with 2-3 minutes of rest between sprints. Such information may make the effectiveness of sprint training more accessible and approachable for individuals unwilling or unable to plan a purposeful REHIIT exercise session into their day. If the rest interval could be prolonged then it may be possible to perform a few sprints as "exercise snacks" throughout the day without the need for a structured interval training session.