"No time to exercise" is no excuse
 

A new study, published in The Journal of Physiology, shows that short bursts of very intense exercise — equivalent to only a few minutes per day — can produce the same results as traditional endurance training.

"The most striking finding from our study was the remarkably similar improvements in muscle health and performance induced by two such diverse training strategies," says Martin Gibala, an associate professor of kinesiology at McMaster University.

Gibala's team made headlines last year when they suggested that a few minutes of high-intensity exercise could be as effective as an hour of moderate activity. However, their previous work did not directly compare sprint versus endurance training.

The new study was conducted on 16 college-aged students who performed six training sessions over two weeks. Eight subjects performed between four and six 30-second bursts of "all out" cycling separated by 4 minutes of recovery during each training session. The other eight subjects performed 90-120 minutes of continuous moderate-intensity cycling each day. Total training time commitment including recovery was 2.5 hours in the sprint group, whereas the endurance group performed 10.5 hours of total exercise over two weeks. Despite the marked difference in training volume, both groups showed similar improvements in exercise performance and muscle parameters associated with fatigue resistance.

"Our study demonstrates that interval-based exercise is a very time-efficient training strategy," said Gibala. “This type of training is very demanding and requires a high level of motivation. However, short bursts of intense exercise may be an effective option for individuals who cite ‘lack of time’ as a major impediment to fitness."

Would disagree with the title
 

Even the "intense" sessions are at least 16 minutes, on a bike, at the track. Presumably already warmed up.

Add after-time, to clean up. Add time-of-day: College students have freedom-of-schedule in a way that grown-ups don't always have. I don't have it in me to do "intense" at the end of the day.