Objective
The nature of the relationship between physiological and subjective responses in phobic subjects remains unclear. Phobics have been thought to be characterized by a heightened physiological response (physiological perspective) or by a heightened perception of a normal physiological response (psychological perspective).
Method
In this study, we examined subjective measures of anxiety, heart rate (HR), and cardiac autonomic responses to flight-related stimuli in 127 people who applied for fear-of-flying therapy at a specialized treatment center and in 36 controls without aviophobia.
Results
In keeping with the psychological perspective, we found a large increase in subjective distress (η2=.43) during exposure to flight-related stimuli in the phobics and no change in subjective distress in the controls, whereas the physiological responses of both groups were indiscriminate. However, in keeping with the physiological perspective, we found that, within the group of phobics, increases in subjective fear during exposure were moderately strong coupled to HR (r=.208, P=.022) and cardiac vagal (r=.199, P=.028) reactivity. In contrast to predictions by the psychological perspective, anxiety sensitivity did not modulate this coupling.
Conclusion
We conclude that subjective fear responses and autonomic responses are only loosely coupled during mildly threatening exposure to flight-related stimuli. More ecologically valid exposure to phobic stimuli may be needed to test the predictions from the physiological and psychological perspectives.

Physiological sensations and discomfort constitute the major symptoms reported by aviophobics. Anxiety sensitivity (AS) seems to moderate the relationship between self-reported somatic sensations and flight anxiety, and AS has been identified as a vulnerability factor for flight phobia. In this study we examined whether AS moderates the effects of somatic sensations and autonomic nervous system reactivity on flight anxiety induced by real flight. In fifty aviophobics participating in Cognitive Behaviour Group Therapy (CBGT), flight anxiety, somatic sensations and autonomic nervous system reactivity were assessed during a guided return flight. Results indicate that physiological reactivity interacted with AS. Changes in heart rate and parasympathetic activity were more strongly associated with changes in reported flight anxiety for high AS participants, and less for participants low on AS. Results did not indicate a moderating effect of AS on the relationship between self-reported somatic sensations and flight anxiety. Our results suggest that therapy for flight phobia might benefit from addressing the physical effect of anxiety, by means of cognitive restructuring and exposure to interoceptive stimuli, particularly in aviophobics high in AS.