OK, so you're buying tissues in bulk these days. You're coughing and sneezing, cursing the pollen count and — maybe worst of all, if you're a committed jogger like me — having your usual hour's run come to a wheezing halt after 20 minutes.

Ah, spring.

But maybe it's not allergies. Maybe it's asthma.

Many adults grew up when only those really dire cases of choking were recognized as asthma, and symptoms were brushed off as "sensitivities" or "sinus problems." But asthma is the most commonly undiagnosed condition in the country, according to Washington immunologist Henry Fishman, and it kills 3,500 to 5,000 Americans every year.

In fact, you may have both allergies and asthma: Fishman says that 80 percent of asthmatics have allergies, and 20 percent of those diagnosed with allergies have asthma as well. Since asthma can be progressive, pollen season may signal it's time to consult an expert.

But Fishman does encourage asthmatics and allergy sufferers to exercise, once the doctor gives the OK. "It's good for the brain, good for the heart, it's good for the bones and good for the soul."

It's particularly important to know your enemy. Fishman, who has consulted on radio, TV and Web site programs, says an asthma attack begins when the trigger allergen is breathed in or when the nasal passages are cooled or dried out. So while it seems a no-brainer to shift to indoor exercise during allergy season, it's not that simple. Some asthmatics react to swimming, for instance: Mold or water-borne pollen brushes the nose, which is being cooled by the water, and ... boom, asthma has you spluttering.

(Parents, you'll want to pay double attention: Asthma is the most common chronic illness in children, but many teens become asymptomatic. Their asthma has not disappeared; it has just gone underground and may reappear later. So talk to your child's coach about any coughing or sluggishness; better yet, take the kids to a doctor before signing them up.)

Regardless, listen to your body when you exercise. If the pollen is only an annoyance, that's one thing. If you feel faint or have trouble working out, cease and desist.

"It is possible to run through an asthma episode," Fishman says, "but it's a terrible idea. ... Macho and asthma don't mix."

For mild allergy symptoms, an over-the-counter decongestant or antihistamine may help.

For more bothersome symptoms, consult your doctor: Fishman is adamant that no OTC asthma medicine is safe.