If this is true I have been doing it wrong the whole time.
According to a recent BBC Article, a genetic trait in some people can allow them to do "high intensity training" (basically: stressing your body to the limit on an exercise, in this example, cycling) for mere minutes a week, and gain many of the benefits of hours of traditional cardio. The idea is doing 20 seconds of "to the limit" cycling, then after a short recovery, another burst, another recovery, etc.
The exact headline is that
A few relatively short bursts of intense exercise, amounting to only a few minutes a week, can deliver many of the health and fitness benefits of hours of conventional exercise, according to new research, says Dr Michael Mosley. But how much benefit you get from either may well depend on your genes.
Assuming you are one of the lucky ones, this seems too good to be true.