BODY WATCH : Outpacing Asthma : Tightness in the chest. Coughing. Shortness of breath. For athletes, exercise-induced asthma can hamstring performance. But there are ways to minimize attacks.

In 1980, after Portuguese runner Rosa Mota had been competing successfully for half a dozen years, something went inexplicably wrong. In races where she should have been finishing among the top three, she began placing 12th or 13th. Her legs felt dead. She just couldn’t get them to move.

She went to doctors, but they couldn’t figure it out. They told her it was psychological. They told her she was too old (she was 21) and past her prime and should quit racing.

Jose Pedrosa, her coach and companion, who was fresh out of medical school, had his own theory. He thought her difficulties might be respiratory related, even though she wasn’t having any obvious breathing problems.

He turned out to be right: She had suddenly developed exercise-induced asthma.

Generally, asthma is a disease characterized by a reversible obstruction--a temporary blockage--of the bronchial airways, the tubes through which people breathe.

The blockage results from inflammation and mucus in the airways, the contraction of the muscles that surround the airways and airway swelling. In most cases, it is triggered by any number of things, including irritants such as tobacco smoke, a cold, allergens (pollen, dust, animal dander) or certain foods.

When exercise is the catalyst, it is called exercise-induced asthma, or exercise-induced bronchospasm. It is a most peculiar affliction, where the symptoms can either be subtle, as they were with Mota, or very obvious. When symptoms are apparent, they typically strike after three to eight minutes of strenuous exercise: chest tightness, coughing, shortness of breath, even dry throat, stomachache and headache. It can last for up to 15 or 20 minutes, and it can affect athletic performance.

“I was diagnosed just after the 1988 Olympic trials,” says U.S. marathoner Kim Jones. “I was running and just couldn’t race. I couldn’t take a deep breath, and I was wheezing. It was a terrible claustrophobic feeling. I actually panicked.”

It is not a new phenomenon. Several centuries ago, physicians were writing about the effect of exercise on breathing. Modern medical literature described exercise-induced asthma in adults at least 50 years ago, and it has been about 30 years since experts reported similar symptoms in children.

But it has been only in recent years that the condition has begun to attract increasing attention--in part because so many well-known athletes have developed it or have begun to speak about it.

They include marathoners like Jones and Mota--who went on to win the 1987 world track and field championships marathon, two Boston marathons and the 1988 Olympic race.

Also Janis Klecker, a member of the 1992 Olympic team, and Joan Benoit Samuelson, who in 1984 won the first Olympic women’s marathon in Los Angeles; Jackie Joyner-Kersee, who earned a silver medal in the 1984 Games, two gold medals in the 1988 Games, a gold in the 1992 Games, and won the long jump and heptathlon in the 1987 world championships. Others include swimmer Nancy Hogshead and basketball player Danny Manning.

In fact, 11% of the athletes who competed in the 1984 Olympics in Los Angeles had some form of exercise-induced asthma, and 1988 Olympic athletes with the condition included five gold medalists, 10 silver medalists and one bronze medalist.

But exercise-induced asthma can strike anyone and can begin at any age, just like regular asthma. The American Academy of Allergy and Immunology has estimated that up to 15% of the population suffers from exercise-induced asthma, including at least 40% of those with hay fever-type allergies and up to 95% of individuals who already have regular asthma. An estimated 12 million Americans have asthma, and more than 22 million suffer from allergic rhinitis (hay fever.)

“Exercise is one of the most common precipitants of acute asthma seen in clinical practice,” says Dr. Gary S. Rachelefsky, director of the Allergy Research Foundation and a clinical professor of pediatrics at the UCLA School of Medicine. “This occurs in people of all ages, although it is more common in children because of their increased physical activity.”

It typically occurs when airway obstruction increases after three to eight minutes of a vigorous workout.

“You can have increasing symptoms over the next five to 10 minutes, and then it goes away . . . usually within an hour,” Rachelefsky says. Occasionally, however, “it can become serious and lead to hospitalization.”

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Experts believe the attack occurs because exercise often involves breathing through the mouth, which introduces cool, dry air. During exercise, the person hyperventilates by taking rapid, shallow breaths. Hyperventilation cools the airways. A reflex reaction to the cooling of the airways can trigger an asthma attack. (Breathing through the nose, on the other hand, helps warm and humidify the air before it reaches the bronchial tubes.)

The condition seems to be at its worst when the weather is cold and dry. Not surprisingly, runners, cyclists, ice skaters and cross-country skiers suffer more than swimmers, who are inhaling moist air from just above the waterline.

Exercise-induced asthma can be very subtle, as it was with Mota--with some people not even being aware of it, except in their performance--or it can be quite severe, as it was with Jones.

“It’s a variant of asthma, but some people don’t even consider asthma,’ says Dr. David Tinkelman, an Atlanta allergist who has studied exercise-induced asthma in high-performance Olympic marathon and 10,000-meter runners.

“They say: ‘I’m in great shape. I don’t have a problem. Just this tightness when I run,’ ” Tinkelman adds. “Well it does exist, but it can exist without people being aware of it.”

Tinkelman studied elite athletes to see whether long-term use of anti-inflammatory agents--which attack the underlying inflammation of the airways--can alleviate the problem and, as a result, enhance performance.

Use of these drugs, known as inhaled corticosteroids, is often standard asthma therapy but is not routinely used to treat the exercise-induced kind. “Yes, it did help high-level athletes,” he says, adding most of them improved their performance times using the therapy--although he says he wouldn’t recommend the regimen for average or recreational athletes.

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There are established ways of preventing exercise-induced asthma through medication and other means, experts say. Athletes who suffer from the condition are usually encouraged to exercise in warm, humid air, or to take up water sports. If this is not possible, it helps to use a scarf or face mask when working out in cold, dry weather. This allows the athlete to breathe air that has been warmed.

Because the condition can subside for two to three hours after an initial episode, elite athletes, such as Joyner-Kersee, routinely provoke an attack through wind sprints or another vigorous warm-up right before competition so they will not be hampered during the event.

“You have it a little bit, and then it goes away for an hour or more,” Rachelefsky says.

Many athletes with the condition also routinely use inhaled medications known as bronchodilators before exercise. These include beta-2 agonists, cromolyn sodium or both. These drugs provide symptomatic relief and thus far are not among those substances banned in international competition.

Rachelefsky adds that if someone is in the middle of a marathon or another event, it is often wise just to keep going when an attack hits--run through it--because it will almost always go away.

“If you stop, it can get worse, so don’t stop,” he says. “Sometimes that’s hard to do, but it works.”

This is the approach Jones takes when she runs a marathon--a 26.2-mile event that the world’s swiftest women typically complete in less than 2 1/2 hours.

“I do go out fairly hard and I go through a mild attack,” she says. “Then I back off, but keep running. Then I take off after I’m breathing efficiently again. I’ve learned to adapt.”