Enduring Questions: Should I run naked?

If you ask me, the ancient Olympians were a lot cleverer than we are. They had the good sense to run, jump and throw in the nude. When you put anything between your skin and the environment, such as shorts and a singlet, you only decrease your body’s cooling efficiency (even if you’re more comfortable in certain areas). The so-called “modern” Olympians of 1896 were cleverer than us, too. They did their running, jumping and throwing in April. Some athletes complained about the chilly, damp weather, but Spiridon Louis gave thanks to Zeus all the way to his (clothed) marathon victory in 2:58:50.

Unfortunately, the Olympic Marathon has been getting hotter ever since. The 1900 marathon started at 2.36pm under a 35°C Parisian sun. Twelve years later, in Stockholm, a Portuguese runner died in the sweltering Olympic Marathon. Many of us remember Gabriele Andersen-Schiess struggling with the effects of dehydration and heat exhaustion in the 1984 Women’s Olympic Marathon in Los Angeles, and staggering across the finish line in the high heat and humidity. In Beijing this summer, both the men’s and women’s marathons will be taking place in average temperatures of 29-31oC, though the city has a record August high of 41.9oC!

"It’s a terrible disservice that the marathon runners will be forced to compete in conditions where they can’t perform their best, and could actually hurt themselves," says Dr William Roberts, medical director of the Twin Cities Marathon and president of the American College of Sports Medicine. To help athletes deal with the hot weather, the US Olympic Committee (USOC) has held educational meetings since before Athens 2004, when it organised a conference focusing on what to expect in terms of heat, humidity and air pollution. "We believe the heat actually opens the window of possibilities for our marathoners," says US men’s Olympic distance coach Bob Larsen. "We’ll leave no stone unturned in our search for scientific approaches to running in the heat."

The lessons learned by the marathon team will also work for you. Here are some of the highlights.

Heat acclimation
Many years of heat acclimation research have convinced most experts that you can do a good job of adjusting to the heat in eight days, a better job in 14, and perhaps better still in 21. The last physiological variable to adapt is your sweat rate, which takes eight to 14 days to reach maximum efficiency. Other, faster responders include increased plasma volume, decreased sodium concentration in the blood, decreased heart rate while running, decreased perceived exertion and increased running economy.

In 2004, prior to the Athens Olympics, US track athletes were given the chance to attend a pre-Olympic training camp in Crete about two weeks before they moved to Athens. The runners followed a heat-training protocol outlined by Randy Wilber of the USOC sports sciences department, who suggested the following: first run in the morning or evening cool; then move to warmer times of the day; finally, increase the length and intensity of your midday workouts.

Perhaps no runner has thought more about heat training and racing than Alberto Salazar. Before the 1984 Olympic Marathon he got tested in a heat chamber (where sweat production is measured) and learned to chug two litres of fluid before every workout. But then he crashed. He now believes he did too many hard 20-milers in the heat. "I was exhausted from the first step of the marathon," he says. He finished 15th in 2:14:19.

Everyone knows drinking fluids is supposed to help you run faster. But you have to slow down to grab your drinks. America’s Steve Spence worked on this dilemma when he was training for the hot, humid World Championships Marathon in Tokyo in 1991. Spence set up a water table on his local track, and then practised drinking while running intervals at faster-than-marathon pace. "I figured if I got good at taking my drinks at this pace, it would come easy in the marathon," he says. Spence claimed the bronze medal.

Alan Culpepper, another 2004 marathon qualifier, visited the Gatorade Sports Science Institute in the US to get a better idea of his sweat production and hydration needs. When he ran for an hour in a heat chamber cranked up to 85 degrees, he sweat 1.4 litres. He also learned that he is a salty sweater. "I’m much more aware now of my drinking and sodium needs," says Culpepper.

Storing extra water would be nice, but runners aren’t camels. Still, two simple substances seem capable of promoting superhydration: common salt, and glycerol – a legal supplement. A New Zealand study showed that well-trained runners who prehydrated with a heavily salted drink were able to exercise for 20 per cent longer in 32.2oC weather than when they prehydrated with a minimally salty beverage.

Not all glycerol studies have shown an improvement in hydration status or endurance performance, but a two-year-old study with Olympic distance triathletes produced convincing results. In a randomised, double-blind, crossover study in 30.5oC conditions, the triathletes slowed down much less with glycerol than without it. "Glycerol lets you increase the amount of standing water on board," says marathon guru David Martin. "It’s nice to have that extra amount during a long, hot race."

Cool Vests
A team from the University of Georgia in the US studied college distance runners covering 5K in a 32.2oC heat chamber with and without ice vests to cool their core before their efforts. The "precooled" runners finished 13 seconds faster, which is more than the gap that will separate many gold-medallists and fourth-place finishers in Beijing.

Cool Clothing
You already know that a white shirt will absorb less heat than a black one. And for the past decade you’ve read about the amazing advances of breathable microfibres. But wait, those shirts are designed to keep you warm and dry in the winter. Do you really want that on a hot summer’s day?

No, you don’t. In 2000, Nike produced a shirt that several runners wore in the Sydney Olympics. This white shirt sat off the skin on small bumps (allowing air to circulate), was constructed of a large fishnet weave (more air circulation), didn’t absorb sweat (leaving it on the skin to cool you via evaporation), and was made of recycled plastic bottles. Too bad Nike called the shirt the Stand-Off Distance Singlet (because of the way it stood off your skin), which sounded too much like a shirt with a body-odour problem. They then went on to produce something called the Nike Sphere Cool Marathon Singlet, with aerodynamic seam placement, mesh construction, and 'Zoned Venting' technology. But give me a Stand-Off Distance Singlet, and I’ll show you a really great hot-weather running shirt.

Here’s my advice to this summer’s Olympic marathon runners: bring your scissors to Beijing and cut your racing singlet as short as you can. Research by exercise physiologist Timothy Gavin has shown that 'the chimney effect' can improve body cooling. This refers to air moving up the bottom of your untucked shirt and out the top. Or just run naked. You’ll be reconnecting with your Olympic forebears, increasing your chances of a medal, and giving a big boost to the BBC’s TV ratings.