To race faster in cool weather just add heat to your training sessions, suggests a new study.
Elite cyclists who regularly worked out in a hot room boosted their performance in cool conditions by as much as 8 percent.
Researchers don't yet know if training in the heat will help amateur marathon runners finally beat their personal bests. But the finding is likely to lead to new training techniques for serious athletes who look for any edge they can get over the competition, said lead researcher Santiago Lorenzo, an exercise and environmental physiologist at the Institute for Exercise and Environmental Medicine in Dallas, Tx. Lorenzo was at the University of Oregon, Eugene, when he did the work.
"I think this study is going to have a big impact on the sports performance world just because it is such a consistent finding," said Lorenzo, who competed in the decathlon at the 2004 Athens Olympics for his native Argentina. "We saw it not just in a few subjects, but in most of them."
Athletes have been training in hot conditions to prepare for hot-weather races since at least the 1940s, when a few classic research papers showed that exercising in the heat helps people better control their core body temperatures.
The technique works because, as the body adapts to hot conditions, sweating begins sooner in response to exercise, and more sweat pours out. At the same time, heat gets diverted to the skin and blood volume expands, all of which helps diffuse heat into the environment.
To find out whether adaptations to heat might also help athletic performance in cooler conditions, Lorenzo and colleagues challenged 20 elite cyclists to three tests of endurance and exhaustion, including a one-hour time trial, along with two 15-minute sessions that progressively challenged cyclists to work harder and harder.
Cyclists did two rounds of the tests in a temperature-controlled lab. In one round, the lab was set to 100 degrees Fahrenheit. In the other, it was kept at 55°F, which is thought to be the ideal temperature for aerobic performance.
Measurements, which included lactate threshold and VO2 max, essentially showed how efficient each athlete could remain at incrementally higher levels of exertion. Overall, the tests measured levels of endurance and resistance to exhaustion.
For the next 10 days, 12 of the cyclists trained in a room that was heated to 104°F. The other eight trained in a room that was cooled to 55. Each day, both groups did two 45-minute sessions with a 10-minute break between them, all at the same level of exertion.
When the athletes repeated the fitness tests, those who had trained in the hot room performed, as expected, better in the hot conditions. More surprisingly, the heat-acclimated group also performed between 4 and 8 percent better in cool conditions, the researchers reported in the Journal of Applied Physiology.
In the real world, that could translate to as much as an 8 percent improvement in speed, distance, or output of power -- a significant boost in a sport that often ends in photo finishes.
"If you look at these races -- first, second, and third places are often very close to each other," Lorenzo said. "A 5 percent improvement may make the difference between winning the race and not making it to the top five."
It makes sense that adapting to heat would help an athlete perform better at 55°F, because heavy exertion still produces a lot of heat at that temperature, said Michael Joyner, a physiologist and anesthesiologist at the Mayo Clinic in Rochester.
Just a slight dip in core temperature makes an athlete feel that much better physically, he added, allowing him to go the slightest bit farther and faster.
The scientists can't say for sure whether heated training would help athletes compete in more wintry conditions. But, Joyner said, even skiers produce as much as 20 times more heat when they exert themselves than they do at rest, suggesting that control over your body's core temperature could help in any conditions.
Joyner pointed to Frank Shorter, who won the 1972 Olympic marathon. The runner lived in Florida for years, and the heat there may have given him a leg up. When Shorter moved to Colorado, he ran in a full tracksuit to simulate the effect.
The new study, Joyner said, lends support to that winning strategy.
"This is pretty good evidence that people might, in fact, want to train in warm weather all the time or do things to make themselves warm all the time," Joyner said. "If someone wants to improve their time, this could be the tip that would help them a little bit."