March 15, 2000 -- Curious how their own running and swimming times stacked up against the world records, a couple of physicists waded into the long debate over whether women's bodies are better suited to long-distance competitions than men's.

In a paper appearing in this week's science journal Nature, they plot the world-record times in running and swimming for racers of both genders and conclude that women are slower than men by the same proportion in both distance races and sprints.

But other physiologists and exercise researchers said the finding is no surprise.

The physicists, Sandra Savaglio of the Space Telescope Science Institute in Baltimore and Vincenzo Carbone of the University of Calabria in Italy, said in races shorter than two minutes, runners and swimmers use more anaerobic energy, which doesn't require oxygen. In races longer than that, they use more aerobic energy, requiring a lot of oxygen.

But no matter how long the race, men and women burn energy at the same rate, they report.

"Any physiologist would tell you this," said Carl Foster, a professor of exercise and sports science at the University of Wisconsin-Lacrosse. "This isn't groundbreaking."

Savaglio, an astronomer, had her interest in athletic performance piqued a few years ago at a swimming competition among high-energy physicists in Europe -- not exactly in the same league as world-class athletes.

The physicists said the results challenge the notion that women's bodies may be better suited to long races. One theory was that women have a higher fat content that can be converted to energy during exercise.

But some exercise experts say that is an outdated assumption about gender differences and athletics. For women, any athletic benefits gained by tapping into their supplemental energy supply would be outweighed by the struggle of carrying the extra fat in a race, they said.

In 1992, a look at world records suggested that women marathoners might catch up with men around 2055, because their times have been improving faster than men's times. Critics bashed the foundation of that paper as a statistical quirk, saying the biological limits would be too much to overcome.