This was at Wired this past weekend:
[S]cience says that most recreational athletes are better off running or riding fewer miles and instead focusing on more intense efforts.
It’s called high-intensity interval training (HIIT), and its benefits have been outlined in an avalanche of scientific papers. A popular HIIT workout comes from researcher Izumi Tabata: Following a 10-minute warm-up, you alternate between 20 seconds of super-intense effort—as fast as you can go—and 10 seconds of rest, repeated for eight cycles. Including a cooldown, the whole workout takes just 20 minutes or so but is surprisingly effective.
This matches some other things I’ve read. Physorg.com, a science website, reports that cardiovascular fitness can be improved, and the risk of diabetes reduced, by brief, high intensity workouts:
A regular high-intensity, three-minute workout has a significant effect on the body’s ability to process sugars. Research published in the open access journal BMC Endocrine Disordersshows that a brief but intense exercise session every couple of days may be the best way to cut the risk of diabetes.
According to the article:
The subjects in this trial used exercise bikes to perform a quick sprint at their highest possible intensity.
Apparently for only three minutes.
No more excuses not to exercise?