Nearly all “asthmatics” will be familiar with a worsening of bronchospasm during exertion.  The mechanism, usually complicating an underlying allergic reaction, relates to increased air flow and work of breathing in a situation where the partly obstructed bronchioles (air conduits) are exerting a “ball-valve effect” that traps air.

“Exercise-Induced Bronchospasm” can be and often is a separate condition.  Some persons, more likely the young and physically active, experience bronchospasm (cough, wheeze, shortness of breath) only on exertion and  in the absence of any underlying allergic or asthmatic disorder.  The mechanism is different and involves temperature changes that occur across the internal bronchiolar lining with increased rate and force of respiration.  Regardless of the reason for the greater respiration, the greater the temperature gradient, the greater the bronchospastic effect.  Thus, exercising in cold, dry environments produce greater reactions than exercising in warm and humid environments.  The reaction is self-limited and is rarely followed by a delayed reaction several hours later (as often occurs in allergic asthmatic reactions).  In fact, the reaction may begin shortly after the exercise has been completed.

The occurrence and also the degree of bronchospasm cannot be predicted from the normality of  pulmonary function at rest.  Thus, a person with  perfectly normal pulmonary function at rest may experience a severe episode of exercise-induced bronchospasm.  This is important also because of the occurrence  in some individuals of “tachyphylaxis” (gradually reducing  bronchospasm episodes) with continued exertion: “working through it”.  But this is unpredictable - and can be dangerous.

Treatment approaches include the commonplace and also the more high-tech:

1. a person so affected should recognize the problem
2. exercise in warmer environment is better than in cold environment
3. use of a thermal mask in cold exposure is helpful
4. warming up before the exercise, and also “warming down” in order to reduce and make more gradual the temperature gradient
5. pre-medicating  with Intal or with Tilade one or two hours before exercising may be helpful
6. a more recent medication is the use of Singulair (10mg orally two hours before exercise - given its prompt effect, its mechanism of action may be its bronchodilator effect  rather than its leukotriene-inhibition effect); and it is probably better than Serevent, which tends to lose effectiveness with time
7. always carry Albuterol as a rescue medication

GS