This study compares the relative efficacy of three methods of delivering interoceptive exposure for the reduction of elevated anxiety sensitivity. The interventions vary according to their intensity and use of coping strategies during exposure. An expressive writing intervention serves as an expectancy control.

Cognitive-behavioral theories posit that panic attacks and panic disorder are the product of inaccurate beliefs about the dangerousness of arousal-related body sensations such as heart palpitations, dizziness, and shortness of breath. Individuals with panic disorder often misinterpret these anxiety symptoms as likely to lead to health catastrophes such as a heart attack, stroke, suffocation, or insanity. Effective psychological treatment aims to correct such misinterpretations by helping individuals learn that their anxiety-related body sensations are not dangerous.

One treatment procedure used to accomplish this goal is "interoceptive exposure," or the deliberate evocation of anxiety-related body sensations via exercises such as hyperventilation, spinning in a swivel chair, or running in place. By demonstrating that the experience of anxiety-related body sensations does not lead to physical catastrophes, interoceptive exposure exercises help individuals learn not to fear their own anxiety symptoms. Indeed, this procedure is considered an essential ingredient in evidence-based psychological treatment of panic disorder.

Despite the established therapeutic value of interoceptive exposure, little is known about how to optimally deliver this procedure. In the most clinically tested panic disorder treatment package, individuals engage in three, minute-long trials of interoceptive exposure exercises such as hyperventilation, with each trial followed by the use of diaphragmatic breathing and a rest period until all anxiety-related body sensations have subsided. However, there are theoretical reasons to question the effectiveness of this method. For example, encouraging individuals to use controlled breathing to "manage" their sensations appears incompatible with the notion that anxiety-related body sensations are harmless. Similarly, the instruction to wait until one's body sensations have subsided to begin the next interoceptive exposure trial suggests that intense body sensations are to be avoided. For these reasons, many practitioners conduct interoceptive exposure in a more intensive manner in which individuals experience feared body sensations in a prolonged fashion, without attempting to suppress or avoid them, until they learn that the sensations are harmless. Despite the theoretical appeal of this latter approach, no studies have examined the effects of delivering interoceptive exposure in this manner. Indeed, very little is known about the effects of different methods of delivering interoceptive exposure on fear of arousal-related body sensations. Accordingly, the present study aims to test the effectiveness of different methods of delivering interoceptive exposure with the goal of generating recommendations for the optimal treatment of panic disorder and other clinical problems associated with the fear of anxiety-related body sensations.

Inclusion Criteria:

• Score > 21 on Anxiety Sensitivity Index - Revised Fear of Respiratory Symptoms Subscale.

Exclusion Criteria:

• Seizures
• Hypertension
• Heart problems
• Pregnancy
• Asthma
• Other health conditions exacerbated by intense exercise.