Earlier this week, the New York Times reported that "Running 5 Minutes a Day Has Long-Lasting Benefits." Since then, a frenzy of news reports have suggested that perhaps 5 minutes of exercise a day is all you need.
But is that actually true?
The New York Times story was based on a new study—published in the Journal of the American College of Cardiology—that analyzed the association of running and risk of death in more than 55,000 adults over 15 years.
During that period, the scientists found that people who ran weekly had a 45 percent decreased risk for dying of heart disease—and a 30 percent decreased risk of death from any cause—than those who didn't run.

For perspective, during that 15-year period, 3,413 participants died of all causes. Of the runners, 4.3 percent died, compared to 6.8 percent of the non-runners. And from heart disease specifically, 1.3 percent of the runners died compared to 2.6 percent of the non-runners.
Those numbers might not sound as dramatic as you might have thought, but they are statistically significant. That means the probability that they could have occurred simply by chance is tiny.
Here's where it gets surprising: The amount a person ran didn't seem to matter.
From the New York Times story:
"Those who hit the paths for 150 minutes or more a week, or who were particularly speedy, clipping off six-minute miles or better, lived longer than those who didn't run. But they didn't live significantly longer those who ran the least, including people running as little as five or 10 minutes a day at a leisurely pace of 10 minutes a mile or slower."
Hence the headline. But there's a catch that the New York Times doesn't tell you about. Turns out, the researchers don't know if the people were actually running as little as 5 to 10 minutes a day. What they do know is that the group who ran the least was accumulating less than 51 minutes of running time per week. It could have been 50 minutes one day a week, or a 15-minute jog on Wednesday, and a 35-minute run on the weekend. Or any combination you can conjure.
I asked Timothy Church, M.D., M.P.H., Ph.D., coauthor of the study and a professor at Pennington Biomedical Research Center at Louisiana State University, to better explain the findings to me.
"Realistically, most people aren't going out for 5-minute runs," says Dr. Church. "But what these findings show is that there is a benefit to running less than 51 minutes a week, and it may not matter how you accumulate that time. That's not necessarily what we should be striving for, though."
If you're looking to get the most health benefits from exercise, Dr. Church suggests you follow the 2008 Federal Physical Activity Guidelines for Americans.
"These guidelines are very well written," says Dr. Church, who was a member of the expert committee that created them. "They're based on  thousands of studies, and recommend at least 150 minutes per week of low-intensity level of activity, like walking, for optimal health benefits."
But, he points out, as your intensity—or effort level—rises, the guidelines say you can exercise for less time to achieve those same benefits. "That's why they recommend just 75 minutes per week if your activity is running, instead of walking," says Dr. Church.
What about 5 minutes a day? "We believe that any activity is better than no activity," says Dr. Church. "So if 5 minutes is your starting point, that's great. But you want to try to increase your activity level over time."
Your activity doesn't have to be just running. In fact, Dr. Church says he would fall into the "less than 51 minutes of running per week" category. That's because he spends a lot more than 51 minutes a week practicing Brazilian jiu jitsu. And exercise doesn't get any more intense than that.
Want to get started running—or make your current plan even better? Check out the Men's Health Running Center.