Olympians to Use High-Tech to Beat Heat

June 2, 2004 — -- It will be hot — hot enough that most locals will have cleared town for cooler havens. But because athletes competing at the 2004 Olympics have no choice but to stay in the sweltering weather, many plan to turn to science to stay cool.

Some will wear vests filled with chilled gel, others will dunk their hands in icewater just before competing and nearly all will be wearing fabrics designed with hot weather in mind.

"Normally we warm up before exercise," said Gordon Sleivert, director of sports science and medicine at the Canadian Sport Center in Victoria, British Columbia. "But in this case we're taking the warm out of warm up. It's like pre-cooling."

Battling heat this summer in Athens could prove as critical a focus as beating record times.

Meteorologists are predicting the average high this August in Athens will be 90 degrees Fahrenheit, with temperatures often reaching above 100 (the average temperature in Sidney for the 2000 summer games was 64).

Humidity will also be a factor, averaging at 41 percent. Although some events, such as the marathon, will start early (7 a.m.) to avoid hot weather, other competitors will be pushing their limits during peak temperatures.

Fighting Heat’s Lulling Effect

In hot weather, more blood is sent to the skin for cooling so less blood flows to your muscles. This means the heart must beat faster to keep up the pace. By some estimates, as much as 75 percent of the body's energy is used to regulate heat when temperatures peak and only 25 percent to power muscles.

Drinking lots of water will help athletes maintain their cool, but humidity remains a problem. The body's ability to cool down is impaired by damp air since sweat drips off the skin rather than evaporates, resulting in dehydration without the cooling.

"When the air temperature is hotter than the skin temperature, our ability to dissipate heat from the body is impaired," said Sleivert. "Getting hot is a real problem because when our brain heats up, the brain waves are more like when you're really sleepy. … Everything feels harder."

Enter technology.

Cool Vests and Ice Buckets

John Surie, president of the U.S. branch of Arctic Heat, has been shipping out his company's version of cool by the crateful to U.S. teams, including the rowing team, swimming team (which will be competing in an open-air pool that's exposed to the blazing sun), triathletes, and canoe and kayak team. The Arctic Heat vest is one of a variety of cooling vests models designed with athletes in mind.

The $175 zip-up vest is filled with a nontoxic gel that maintains its temperature for a long period of time. The idea is to chill the vest before use, wear it during warm-up to keep the body temperature down and shed it just before competition (rules prohibit athletes from wearing them during competition).

"The cooling vest is as high-tech as we will be getting," said Brian Pearsons, spokesman for the U.S. canoe and kayak team.

Sleivert says his company, PacificSport, has developed a similar garment called the Thermal Blazer, that Canadian teams will don before competition.

But not everyone is sold on the concept.

Members of the Scottish Sprint Cycling team, for example, have argued the technology constricts the body's blood vessels and is counterproductive. Their trick to staying cool? Plunging their hands in a bucket of ice water to cool the blood.

Clothing companies, meanwhile, have developed a variety of fabrics to beat the heat. Adidas ClimaCool technology uses so-called micro ventilation in its fabric to pull sweat across the surface and through the clothing and incorporates conductive tape in key areas to dissipate heat.

Reebok has built a similar trick into its clothing with crevices designed into the fibers of a garment to draw water molecules away from the body. Mesh panels in the clothes add ventilation. Nike's clothes have a built-in evaporation system and strategically placed ventilation.

Oddly enough, some athletes will be wearing wool this August. Woolmark's Sportwool steps outside of wool's traditional insulating role to provide a cooling effect. The cooling clothes are made from a polyester outer layer and a superfine Merino wool inner layer take advantage of wool's natural drying effect.

"Thanks to the inner wool side, you get no clingy fabric even when exercising," said Carl Brescia, vice president of sales for Woolmark America.

Hot Training

But high-tech fabrics aside, Sleivert argues the best way athletes can combat hot weather is to train for it.

Just as competitors try and acclimatize to higher altitudes, athletes can help their bodies adjust to heat by elevating their body temperatures regularly during training. This way, says Sleivert, the resting body temperature can be lowered by a degree or so.

To test how well Canadian athletes are adjusting to warmer weather, Sleivert has some swallow a pill about 2 cm long that contains a tiny thermometer and transmitter. This way coaches can monitor the athlete's core body temperature throughout training and determine what factors might help keep it lower. The pill then passes through the athlete's system within about a day.

"To perform at their peak level," Sleivert said, "Athletes will need to re-set their thermostats."

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