Gretchen Reynolds, a New York Times health blogger, summarizes a study of thousands of marathon runners. Abbreviated version:

• The researchers wound up with information about 91,929 marathon participants, almost 42 percent of them women. The data covered all adult age groups and a wide range of finishing times.

• They compared each runner’s time at the midpoint of his or her race with his or her time at the finish, a simple method of broadly determining pace. As it turned out, men slowed significantly more than women racers did. In aggregate, men covered the second half of the marathon almost 16 percent slower than they ran the first half. Women as a group were about 12 percent slower in the second half. Burrowing deeper into the data, the scientists categorized runners as having slowed markedly if their second-half times were at least 30 percent slower than their first-half splits. Far more men than women fell into the markedly slower category, with about 14 percent of the male finishers qualifying versus 5 percent of the women.

• This disparity in race pacing held true in all age groups and finishing times, the researchers found, even among the fastest runners. The difference, however, was most pronounced at the back of the pack. There, female runners were much more likely than men to steadily maintain the same, less hurried pace throughout.

• Using this data to adjust for marathon experience, the researchers found that men, however many marathons they had completed, were still more likely than equally experienced women to slow during the second half of a race.

• The study was not designed to determine why men more frequently fade during marathons. But the reasons are likely to be physiological and psychological said . . . the senior author of the study. “We know that at any given exercise intensity, men will burn a greater percentage of carbohydrates for fuel than women, and women will use more fat. Our bodies, male and female, contain considerably more fat than stored carbohydrates. So men typically run out of fuel and bonk or hit the wall earlier than women do.”

The study’s senior author also found that men are more prone psychologically to adopt a “risky strategy” in their early pacing. “They start out fast and just hope they can hold on,” she says. She points out that strategy can sometimes pay off in a swifter finishing time. “It’s not necessarily a bad thing to push yourself at the start of a marathon,” she says, “if you have not catastrophically overestimated your capabilities. And Hunter notes, “An evenly paced race is not a well-paced one, if you run slower than you were capable of running.”

Reynolds, the Times blogger concludes, “The message of the study, then, would seem to be that an approach to marathon pacing that borrows something from men and women might be ideal. Maybe go a bit harder than you think you can in training, aiming to calibrate what your actual fastest sustainable pace is. Then stick with it during the event, even if your training partners tear away like rabbits at the start. You’ll reel them in.”

Unless there’s a large percentage of women with “gas in the tank” at the end of marathons, which I highly doubt, this conclusion strikes me as odd. As the study’s authors acknowledge in the larger post, evenly paced marathons are almost always faster than uneven ones; therefore, it’s logical to conclude that women marathoners, on average, are tapping more of their potential on race day relative to men.

And why are men running out of fuel and bonking earlier then women? It doesn’t matter that men “burn a greater percentage of carbohydrates for fuel” when every race provides ample fluid and carbs every few miles. Why don’t men do a better job replacing what they’re burning? Are women more intentional then men about integrating race simulation long runs in their training? Are men more prone to winging pacing and nutrition on race day?

Even if the study wasn’t designed to address why men are more prone to run too fast too early, I have a theory. I used to run with a friend who routinely sped up whenever we came upon a female runner or two on our wooded trails. He wasn’t conscious of this quirk. That experience, plus two decades of watching mostly male marathoners start out way too fast, makes me think male runners’ egos get the best of them.

When passed by older runners, heavy runners, really young runners, or heaven for bid, female runners, the self conscious male runner is prone to pick up his pace, with disastrous results an hour or two later.

Knowing this, I always strive to run my own race based upon the quality of my pre-race training. Consequently, when you pass me at a future race, I will wish you well.

Postscript—during today’s 5.5 miler, I realized my playlist needs some tweaking. Which of these doesn’t fit?

Bonus vid for making it to the finish line.