To the Editor: Andreas Broocks, M.D., and colleagues (1) say that in their controlled trial, the therapists avoided exposure techniques. However, aerobic exercise (running) itself is a method to induce prolonged exposure to feared agoraphobic situations along the 4-mile route (park or forest) near home. Asking patients to complete the route at least three times a week and to present activity diaries weekly to the therapists can be seen as further exposure/homework instruction. Moreover, as the authors note, running exposes patients to the internal feared cues of palpitations, sweating, rapid breathing, and the like that are induced by exercise. The two patients who panicked while running continued to run and improved within 15 minutes, as usually happens during exposure therapy. Exercise per se, however, may not induce exposure to all of the cues that panic disorder sufferers fear in the manner required for optimum outcome. The study may have achieved even more improvement had its exposure been tailored to involve all of the patients’ feared cues systematically rather than just incidental to the exercise schedule.