a mere 20 minutes a week of any physical activity, whether sports, walking, gardening or even housecleaning, the last not usually associated with bringing out the sunshine. The researchers found that more activity conferred more mental-health benefits and that “participation in vigorous sports activities” tended to be the “most beneficial for mental health.” But their overall conclusion was that being active for as little as 20 minutes a week is sufficient, if your specific goal is mental health.
In other words, six minutes or so a week of hard exercise (plus the time spent warming up, cooling down, and resting between the bouts of intense work) had proven to be as good as multiple hours of working out for achieving fitness. The short, intense workouts aided in weight loss, too, although Gibala hadn’t been studying that effect.
http://well.blogs.nytimes.com/2009/12/30/phys-ed-how-much-exercise-to-avoid-feeling-gloomy/
http://well.blogs.nytimes.com/2009/06/24/can-you-get-fit-in-six-minutes-a-week/