PART 2 – CAFFEINE
In part 1, we reviewed exercise-induced asthma and found that it affects almost all persons who suffer from asthma, 1/3 to 1/2 of those with allergic rhinitis and even 5-10% of healthy people. EIA is usually diagnosed when exercise causes coughing, wheezing, shortness of breath, chest tightness and premature fatigue. We found that dietary salt exuberates the degree of bronchospasm EIA patients encounter following exercise and learned that forced expiratory volume (FEV1) [the amount of air that can be forcefully exhaled in one second after taking a deep breath] has greater declines in EIA patients who consume more salt. (A post-exercise FEV1 reduction over 7% indicates abnormal pulmonary function. Exercise-induced asthma is defined by a 10% or greater reduction in FEV1 following bronchoprovocation.1) this month we will focus on how caffeine can help.
In a 1990 study2 11 patients with EIA received one of three treatments 90 minutes prior to a dry gas challenge which served as an exercise surrogate. The groups either had a placebo, moderate caffeine (5 mg/kg of body weight) or high caffeine (10 mg/kg of body weight). The results were as follows: FEV1 declined to 16.7% with placebo, 10.2% with moderate caffeine, and 7.1% in high caffeine In a 1991 study, ten patients with EIA received one of three treatments two hours prior to exercise on three occasions.3 The intervention was either a placebo, a moderate amount of caffeine (3.5 mg/kg of body weight), or a high level of caffeine (7 mg/kg of body weight). The results were as follows: Forced expiratory volume1 (FEV1) declined 25% with the placebo, 14% with moderate caffeine and only 10% with high caffeine.
In conclusion, unless a person who suffers from EIA is caffeine intolerant, it is definitely worth their while to try caffeine before they exercise. I let the patients choose the delivery system – a strong cup of brewed tea or coffee, caffeine containing energy drink or fat burner supplement, or a no-frills ‘stay awake’ caffeine pill. In these tight economic times, helping a patient with asthma breathe easier during exercise -- without costly supplements or additional treatments -- by simply advising them to have some caffeine (before activity) and lower their salt can be very rewarding when they tell their families and friends how much you helped them.
1. Rundell, J.W., Wilber, R.L., Szmedra, L., et al. Exercise-Induced Asthma Screening of Elite Athletetes; Field Versus Laboratory Exercise Challenge.
Med. Sci. Sports Exerc. 2000;32(2) p.309-316.
2. Duffy, P., Phillips, Y.Y., et al. Caffeine Consumption Decreases the Response to Bronchoprovocation Challenge with Dry Gas Hyperventilation. Chest. 1991;99(1374-1377),
3. Kivity, S.Y., Ben Aharon, A., Opalsky, M. The Effect of Caffeine on Exercise-Induced Bronchorestriction. JEST 1990;97:1083-1085.