Asthma and sports

The 2010 Winter Olympics kicks off on February 12th, in Vancouver, British Columbia, Canada. We’ve found some news items spotlighting issues of allergies and asthma for Olympic athletes.

The New York Times published an article on January 13, 2010, asking why as many as 50% of winter sport Olympians have exercise-induced bronchoconstriction (EIB). Yale University allergist, Christopher Randolph, MD, pointed out that EIB, in the absence of asthma, tends to occur in athletes who train for the greatest number of hours, especially in cold weather. So, does cold weather actually cause EIB?

The conventional wisdom has been that EIB is a constriction/dilation reaction to cold air, like numbing/tingling of the fingertips. More recently, researchers now consider the primary cause to be airway dryness. Abrupt moisture loss in the airways causes mast cell degranulation and cytokine release leading to acute inflammation. Recent research in EIB subjects points to dysregulation of aquaporin water channels (Chan et al., Chest 2008).

But this doesn’t answer the question of EIB prevalence in winter sport athletes. One new theory, mentioned by Dr. Randolph, suggests that EIB in winter sport athletes is a sports injury. Chronic inflammation associated with excessive exercise-related respiration may produce the airway injury.

A Canadian Broadcasting Corporation news article takes up the topic of athletes with allergic rhinitis. Dr. Donald Stark, an allergist in Vancouver, commented that February is alder tree pollen season in southwest B.C. He warned that athletes that are not allergic to alder may cross-react if they are sensitive to birch. This is a particularly problematic issue as over-the-counter medications can produce “doping” results, which would immediately disqualify the athlete. Olympic athletes are allowed to take pseudoephedrine, though blood titers cannot be higher than 150μg/ml.

On a sort of related, summer Olympic event note…
Belgian researchers published results in the European Respiratory Journal on their study of infant swimming and bronchiolitis. They found that infants younger than 2 years that swam in indoor or outdoor pools had increased risk of bronchiolitis compared to their non-swimming peers. The researchers suggested that early exposure to chlorine made the airways more sensitive and reactive to infection as well as allergens.

Children who swam in indoor pools had 3.5 times higher risk and children who swam in outdoor pools had twice the risk of bronchiolitis. Infant swimmers with a history of bronchiolitis also had increased risk of asthma and allergies later in life.

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