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MOTOR racing drivers are becoming an increasing danger to themselves and
others. It鈥檚 not bravado, but heat and high levels of carbon monoxide that are
seriously impairing some competitors鈥� ability to drive. Safety measures such as
fire-retardant suits only make the problem worse.

Timothy Ackland at the University of Western Australia鈥檚 Department of Human
Movement and Exercise Science in Nedlands and his colleagues made the discovery
while running tests on drivers from the US National Association of Stock Car
Automobile Racing.

鈥淚t is most certainly dangerous,鈥� says Ackland. 鈥淎necdotally, NASCAR crew
chiefs have reported their drivers being unresponsive to directions, showing
erratic skill and even blacking out at the end of races,鈥� he says. Some drivers
fail to realise that they have finished the course, he adds.

Circular or oval tracks produce swirls of air around the course which prevent
carbon monoxide in exhaust gases from escaping, says Ackland. Changes in design
have led to cars becoming more cramped, with the engine and
transmission鈥攎ajor sources of heat鈥攅ven closer to the driver.

Heat or high levels of carbon monoxide can impair the ability to control
motor function, says Ackland. 鈥淏ut when these stressors are met in combination,
the resulting effect is multiplied.鈥� The effects are further exaggerated in
high-performance sports where a driver鈥檚 heart rate can stay elevated for a
considerable amount of time.

Ackland, together with Scott Walker and Brian Dawson, tested eight elite
drivers in a NASCAR simulator. The researchers put the simulator in a sealed
chamber and exposed drivers to different conditions designed to mimic a typical
stock car race. They raised the ambient temperature as high as 50 掳C, and
introduced controlled amounts of carbon monoxide. Drivers were also exposed to
heat alone, as well as a control race at 20 掳C in clean air. They tested
psychomotor performance by getting the drivers to press buttons in response to
certain events.

Heat and carbon monoxide made the drivers鈥� performance significantly worse,
the team found. Most mistakes were made during cornering.

Ironically, some of the safety measures brought in to protect drivers put
them at greater risk, Ackland says. 鈥淭he driver is hampered in his ability to
dump heat because of the mandatory fire retardant suit, gloves, boots and helmet
that trap a layer of moisture next to the body.鈥�

What鈥檚 more, drivers are fed air through vents to try to keep them cool. But
cars often tailgate one another to reduce air resistance. 鈥淭his takes air
directly from the track environment, which has a high concentration of carbon
monoxide from the other cars鈥� exhausts,鈥� explains Ackland.

The fitter drivers are, the better they will be able to tolerate these
factors, he says. But the best solution would be to develop a light-weight
device to cool and clean the air being fed to the driver.