You’re Looking a Little Ozoned-out
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Outside magazine, October 1995
You’re Looking a Little Ozoned-out
When it comes to the air you breathe, what you can’t see will hurt you
I have a friend who’s always complaining about the tribulations of running in his own New York City: the paroled sociopaths, the anxious taxi drivers, the street drones pressing handbills into palms. But he rarely mentions Gotham’s–make that any city’s–only surefire danger, the air.
“When the air conditions are particularly bad, you might just be better off staying indoors,” says David Martin, a physiologist at Georgia State University and chair of the sports sciences committee of USA Track & Field. “If the only time you can run is 5:30 in the afternoon and you choose Fifth Avenue in Manhattan, you could certainly question whether the cardiovascular
While the perils of sucking down dark brown diesel fumes may seem obvious, the harsher truth is that we often can’t see or smell the nastiness we’re inhaling. Pollutants such as nitrogen dioxide and sulfur dioxide, acid particles, and the two most notorious airborne kamikazes, ozone and carbon monoxide, can affect you on a blue-sky day. And certain pollutants will carry and
Of course, it doesn’t help that we athletes love our oxygen. An adult at rest consumes about eight liters of air per minute. During mild exercise that can jump to 25 liters; go all-out and you can pull in 100. To add insult to intake, once this “minute volume” exceeds 30 liters, it’s difficult to funnel it all through the nose, where large particulates are easily trapped by
Dodge the Ozone
Unfortunately, though you can run from L.A., it’s hard to hide from ozone. The U.S. Environmental Protection Agency has determined that air containing ozone at a level of 0.12 parts per million is unfit to breathe for more than an hour. Los Angeles regularly exceeds that figure, but the numbers also occasionally get that dismal in Milwaukee, El Paso, Texas, and Portsmouth, New
Or, perhaps thanks to your genetic makeup, you might not. Two recent tests by the EPA’s National Health and Environmental Effects Research Laboratory showed that sensitivity to ozone varies greatly. One test group worked out steadily and moderately for 6.6 hours–about the length of a good day hike–and even at ozone levels as low as 0.08 parts per million a significant number
Horstman and his colleagues are still searching for the exact physiological reason for those results, but they have nailed down the fact that we have all learned to tolerate a little ozone. It’s another way in which humankind, for better or worse, has adapted: Studies have shown that while reaction to ozone gets worse on the second day of exposure,
How to beat ozone has been the recent subject of much magic-pill debate, what with the emergence of so-called antioxidant supplements rich in vitamins C and E. But tests of the effectiveness of such remedies have been inconclusive at best–so the most sound advice is still to practice ozone avoidance. On sunny days, exercise in the morning, before traffic spills heaps of
Keep Carbon Monoxide Out of Your Sink
Carbon monoxide is just as common a pollutant as ozone, but it’s not as apparent a threat to athletic performance. Like ozone, it’s a gas, yet it doesn’t irritate the airways. It also doesn’t disperse as widely as ozone. In fact, one study showed that bike messengers, who spend their days zipping in and out of traffic, had lower than average concentrations of carbon monoxide in
And, most likely, less exposure than the rest of us get just chugging down city sidewalks. It’s then, when we get carbon monoxide in large doses, that our performance can be severely impaired. “Without wind to whisk it away, there’s only one sink to suck in carbon monoxide,” says Gong. “That’s blood.”
Each carbon monoxide molecule that enters our lungs attaches to a hemoglobin molecule in our blood, taking up the space usually reserved for oxygen. It does so tenaciously–carbon monoxide’s affinity for hemoglobin is 200 times greater than that of oxygen–and in the process shoves oxygen molecules out of the way, reducing the amount that goes to feed the muscles. Normally,
Fortunately, if you veer away from traffic and into a park, you should stay well below that figure. But even on a sequestered path you’re not out of the pollutant woods. “Someone running around the reservoir in Central Park may think, ‘Gee, it’s nice to get away from that bad air,’ ” says physiologist David Martin. “Remember, that dust on the track can get into your lungs–it’s
Mark Jannot wrote about 40-minute workouts in the July issue. He is a frequent contributor to Bodywork.