THE DANGER OZONE : Exercising in L.A. Smog Bowl Carries Risk of Respiratory Problems

Although smog levels have been unusually low this summer in fitness-crazed Los Angeles, people who disregard air quality during exercise may be gambling with their health, cautions Robert F. Phalen, director of the Air Pollution Health Effects Laboratory at UC Irvine.

“Exercise and smog is a dangerous combination,” Phalen said.

“Vigorous exercise forces the lungs to inhale eight to 10 times the air breathed at rest. That’s eight to 10 times the amount of pollutants. In laboratory animals, if you just double the breathing volume you can get up to 10 times the amount of lung damage.

“There is little doubt that the same principles apply to humans.”

Compounding the potential for lung ailments such as emphysema and bronchitis, said Phalen, is that most people breathe through their mouths while exercising. Nose breathing is better because the nasal passages filter out as much as 90% of the air’s sulfur dioxide as well as smaller percentages of lead, ozone and other gases. Without filtration, pollutants rush almost unimpeded into the deep recesses of the lungs.

Children are especially vulnerable in a polluted environment, Phalen said. In a 1983 study at UC Irvine, it was discovered that children receive heavier deposits of air pollution in their bronchial regions than adults.

“Children should never be forced to exercise on smoggy days,” Phalen said.

Although air pollution has been linked to cancer and lung disease in laboratory animals, it is only suspected to cause cancer in humans. But the circumstantial evidence is there, Phalen said, mentioning the fact that cancer rates are higher in polluted urban settings than pollution-free rural environments.

“People are not rats and mice, but their lung structure is similar,” Phalen said. “Their lungs respond to injury in similar fashion. From the kinds of lung injury from ozone we have been seeing now in animals, there is little doubt they can occur in people, too.”

Even schoolchildren are supposed to know the perils of exercising “in heavy smog.” But there’s a question today on just how heavy is heavy? Last year, air pollution studies concluded that ozone, the most pervasive element in Southern California smog, has more acute health effects at lower concentrations than previously thought. The Federal Clean Air Standard of .12 parts per million is now thought to be too high.

“For people like joggers, when you consider the extreme doses of ozone they receive,” Phalen said, “the federal standard probably does not give them an adequate safety factor.”

At this time of year in Los Angeles--which has the foulest air in the country, according to a recent study--smog levels are at their peak. In at least one area of the 6,000-square-mile South Coast Air Basin, ozone will reach .12 ppm almost every day this summer. Since 1982, there have been nearly 400 days in which ozone levels reached .20 ppm, and readings of .35 ppm or higher have occurred 10 times.

“Scientists are finding in studies on laboratory animals an increased susceptibility to infection at levels of .20 parts per million of ozone,” Phalen said. At the same levels, he said, changes in lung structure also are being found. At slightly higher levels, he said, “We’re finding an increased susceptibility for cancer in cancer-prone animals.”

Phalen believes that joggers should be keenly aware of daily air quality. But judging by the number of people who work out at all the wrong times of day, smog doesn’t seem to be as important to them as body mechanics, running shoes and vitamin supplements.

At 5 p.m. on a recent weekday, Suzanne Potashnick was taking a jog in the smog on the grassy median of heavily trafficked San Vicente Boulevard in Brentwood. Exhaust fumes from hundreds of passing cars were turning the street into what smog researchers call a carbon monoxide canyon. Exercising inside one of these canyons for an hour, Phalen said, is roughly equivalent to chain-smoking cigarettes for 20 minutes.

Although Potashnick considers herself a practitioner of the Southern California life style, which emphasizes health awareness, she says she doesn’t check daily smog levels and didn’t know that her choice of workout hour and location could not have been worse. Smog, including carbon monoxide, is at its peak from 2 to 6 p.m.

“No wonder I call it black-lung jogging,” she said when told what she was breathing. “Maybe that’s why when I get home I cough a lot and often feel sluggish.”

Why is she indifferent to smog?

“If you want to stay in shape, sometimes you can’t be picky about the time and place,” she said. “Anyway, I never heard of jogging people dying of smog.”

But jogging rats have. Ozone scorches lung tissues, according to Phalen, with an effect “similar to sunburn.” Heavy doses of ozone during exercise can cause coughing, respiratory soreness and impaired lung function--discomfort that prompts most people to stop working out.

But in a 1981 experiment at UC Irvine, a group of 10 rats were trained to exercise in air that was .80 parts per million of ozone--a level that was occurring in Los Angeles only 30 years ago. Two of the rats died--the ozone caused fatal hemorrhaging in their lungs. When autopsies were done on the other eight rats, it was disclosed that the lungs of all eight, Phalen said, “were incompatible with survival.”

What makes lung damage even more likely in some people is the “make it burn” mentality. Michael Clark, who jogged almost every afternoon at Balboa Park until recently, ignored his burning lungs because he assumed they were supposed to hurt if he were going to improve his performance.

“I thought the saying ‘no pain, no gain’ applied to jogging,” said Clark, who also occasionally suffered from headaches after running. When he changed to workouts in the morning, the burning stopped and the headaches disappeared.

The 1984 Summer Olympics sparked research into the short-term impact of smog on performance, but little was learned about its effect on health.

At UC Davis, Prof. William C. Adams studied elite athletes in a controlled indoor environment and found that exposure to as little as .188 ppm of ozone for 30 minutes initially had a negative effect on 50% of the athletes. That figure went up to 70% at .24 ppm of ozone. Performance decreased nearly 12% at the higher ozone levels.

But Adams also found that the athletes somehow adapted to the smog. When they were exposed to the same ozone levels one to two hours a day for four to five days, they no longer suffered respiratory discomfort and their performances returned to former standards.

That research seems to suggest that people who jog frequently can adapt to smog as it relates to their performance. But adaptability has its limits, according to Dr. Jack Hackney, director of research at Rancho Los Amigos Hospital in Downey.

Hackney, in another pre-Olympic experiment, exposed volunteers to high levels of ozone during exercise for several successive days. Some of them developed a tolerance, he said, but it was short-lived.

“After less than a week, it had gone away,” he said, concluding: “Tolerance can’t be relied on as adequate protection. It’s transitory and doesn’t occur in all subjects.”

Three years ago, Henry Gong Jr., a smog researcher at the UCLA School of Medicine, studied elite cyclists, working them out in a chamber with high ozone levels. He found that all the negative changes that occurred in their performances and lung function were reversible once the ozone was reduced.

“But we don’t know if this happens in the real world,” he said. “In the real world there is more than one pollutant. In a chamber you eliminate these variables.”

A lot of people think they can beat the smog by exercising indoors. But even though smog levels are reduced by 50% indoors, Phalen says, the air is still unhealthy. Indoors, there is less air to dilute pollutants, and there are a lot more pollutants.

In addition to smog, indoor air contains the germs people expel while working out; the several million skin flakes that each person sheds every minute (there are an average of two microorganisms on each flake); and dust mites, which are spiderlike creatures that live wherever dust collects (carpets, books, furniture) and turn into an allergic substance when they die.

Air conditioners can’t be relied on to sanitize the air. They often do more harm than good, according to Phalen. “Air conditioners are traditionally associated with problems of their own,” he said. “A well-designed system does a lot to keep the air clean, but some have humidifiers that are the sources of mold-producing spores, and most don’t have high-quality filters.”

Because of the weather and geography in Los Angeles, smog is here to stay, but that doesn’t mean joggers or cyclists and other outdoor sports enthusiasts can’t take steps to protect themselves.

Even though it may only be visible in the distance, smog is everywhere, lurking as close to the ground as the morning dew. It is at its worst from mid-April to mid-October, particularly during the afternoons, so workouts should be planned for the early morning or late evening. It is also advisable to check smog tables and smog forecasts in newspapers. Smog levels are predictable a day in advance.

And even though it isn’t yet fashionable, wearing a surgical mask impregnated with activated charcoal will effectively filter most pollutants, including gases.

Smog is usually not a problem during periods of stormy weather and from the second week of October to the second week of April. However, severe carbon monoxide episodes are likely to occur about half a dozen times in the winter, although early afternoon workouts shouldn’t present a health problem.

Are there any areas, besides an oxygen tent, to go to avoid smog? If the smog-trapping inversion layer is low enough--and it can be as low as 200 feet--some areas in the hills and mountains may be above the yellowish-brown cloud. But if the inversion layer is low, smog in the valleys will be thicker than usual.

Exercising at the beach is relatively safe at almost any time of the year because ocean winds carry pollutants inland. But so-called acid fog, which has begun to occur at the beach, could prove to be a concern. It appears during darkness and in the early morning and cold weather.

Swimming pools also provide some protection from smog because water absorbs pollutants, thereby diluting their concentration in the air around the pool. But swimmers should be aware that while they’re avoiding smog, they are also being exposed to chlorine and microorganisms such as bacteria and algae.

“You can’t tell people to stop exercising because, in theory, it’s good for them,” UCLA’s Gong said. “But they just have to use common sense.”