Heartbeat awareness and heart rate reactivity in anxiety sensitivity: a further investigation

We examined the effects of anxiety sensitivity (AS) and arousal induction on heartbeat awareness and heart rate reactivity in a nonclinical undergraduate sample. Students were randomly selected from a larger screening sample to fill two groups (high and low AS; n = 15 per group) based on Anxiety Sensitivity Index (ASI) [Peterson, R. A., & Reiss, S. (1992). Anxiety Sensitivity Index manual (2nd ed. revised). Worthington, OH: International Diagnostic Systems] scores. Participants completed a mental arithmetic/spelling task to induce arousal. At two phases (i.e., baseline vs. stress), participants estimated their heart rates during specified intervals using a mental tracking paradigm. Actual heart rates were simultaneously measured. Although heart rate did increase significantly from baseline to stress phases, high and low AS groups did not differ in terms of heart rate reactivity to the stressor. As hypothesized, high AS individuals were more accurate in estimating their actual heart rate as compared to low AS individuals. Contrary to hypothesis, the AS group differences in accuracy of heartbeat estimations did not vary across baseline vs. stress phases. Interestingly, only low AS individuals provided heart rate estimates which were significantly lower than their actual heart rate readings. Although high and low AS individuals did not differ in actual heart rate, high AS individuals provided significantly higher heart rate estimates than low AS individuals. These results are consistent with the interoceptive sensitivity hypothesis. Implications of the greater heartbeat awareness of high AS individuals are discussed.