The study subjects included nine healthy patients with the classic form of CAH who demonstrated good hormonal control and nine healthy volunteers matched for gender, age, and body mass index. Each subject completed three exercise tests over three days, including a test to determine fitness level and two standardized tests. CAH patients received their normal morning dose of hydrocortisone and florinef an hour before exercising as well as either an additional dose of hydrocortisone or a placebo (inactive substance) before the standardized tests. The hydrocortisone and placebo pills looked the same, so patients did not know which one they were taking. After the series of three exercise tests was completed, the CAH patients were asked during what session they believed they had received the extra dose of hydrocortisone.

Although the additional morning dose of hydrocortisone resulted in about a doubling of blood cortisol levels, these levels decreased over time. Furthermore, the stress dose of hydrocortisone did not appear to affect blood glucose levels, adrenaline, or other glucose-regulating hormones (glucagon, insulin, growth hormone), exercise capacity or perceived exertion during exercise. Instead, glucose and adrenaline concentrations in CAH patients with and without a double dose of hydrocortisone remained lower than the levels observed in matched, healthy controls. Also, as described in the previous exercise article, the normal exercise-induced rise in glucose was not observed in the CAH subjects. Interestingly, only one patient was able to correctly guess which day he had received the stress dose rather than the placebo.

While administering extra hydrocortisone during a period of physical stress such as in illness or injury has been shown to be beneficial, our data suggest that patients with the classic form of CAH do not benefit from extra hydrocortisone during short-term, high-intensity exercise. In addition, unnecessary and excessive use of hydrocortisone can actually cause a myriad of adverse effects on the skin, bones, body composition and heart. Because the benefits of stress dosing before exercise have not been supported by research and the potential side effects are detrimental, the regular use of extra hydrocortisone with exercise is not recommended. At the National Institutes of Health Clinical Center in Bethesda, Maryland, we are currently studying CAH patients undergoing 90 minutes of exercise and will soon have additional information regarding longer-term exercise in patients with CAH.