Super-short workouts are all the rave in media space.
Gretchen Reynolds of The New York Times wrote in Feb. 2007, in an exaggerated example of exercise porn, that she had written about seven-minute, six-minute, four-minute, and even one-minute workouts. They are appealing because they require so little time, but they also demand straining effort.
Martin Gibala is the scientist we most have to thank for the popularity of very brief, very hard exercise. All of these workouts are built around the concept of high-intensity interval training, in which you push yourself almost to exhaustion for a brief spurt of minutes or seconds, and then rest and recover for a few minutes before repeating the intense interval.
45-seconds shifts, go hard or go home, and do it again.