Acute exercise reduces the effects of a 35% CO2 challenge in patients with panic disorder

Background: Chronic exercise has been shown to have therapeutic effects in panic disorder (PD). The mechanism of these effects is unknown. Acute exercise reduces the effect of a panic challenge in healthy volunteers. Such an effect has not yet been demonstrated in PD patients. The present study aimed at exploring the antipanic effects of acute exercise on a 35% CO2 panic provocation in treatment-naive PD patients to further elucidate the mechanisms of the beneficial effects of exercise on panic. Methods: Eighteen PD patients performed either moderate/hard exercise or very-light exercise before a 35% CO2 challenge in a randomized, between-group design. The reactivity to CO2 was assessed with the Visual Analogue Anxiety Scale and the DSM-IV Panic Symptom List. Results: Panic reactions to CO2 were smaller in patients that performed moderate/hard exercise in contrast to those that performed very-light exercise. Increments in both measurements and panic rates were consistently reduced by intense exercise. Limitations: Since this study focuses on the acute effects of exercise on CO2 sensitivity in patients with PD, the results of repetitive exercise sessions on the rate of spontaneous panic allacks and overall symptoms are warranted. The small sample size and other limitations are addressed. Conclusions: Exercise reduced the panicogenic effects of a CO2 challenge. In addition to its therapeutic potential, exercise may also be useful as a laboratory maneuver with heuristic value in experimental research into the mechanisms of antipanic treatment. (C) 2007 Elsevier B.V All rights reserved.