Heartbeat perception, instructions, and biofeedback in the control of heart rate

The present study was designed to examine the possibility that individual differences in heartbeat perception and instructions to control heart rate (HR) may influence the acquisition of voluntary control. Good (n = 20) and poor (n = 20) perceivers of cardiac activity were selected on the basis of their performance according to Whitehead et al. (1977) heartbeat discrimination procedure. Measures of state and trait anxiety (the State-Trait Anxiety Inventory Form X-1 and Form X-2) and Tellegen's Absorption Scale (TAS) were used to assess emotionality and absorptive ability. Good and poor heartbeat perceivers (a) were given non-motivating instructions to try to either increase or decrease their heart rate (HR) with, or (b) without the use of HR-feedback, and (c) were given motivating instructions to try to either increase or decrease their HR with, or (d) without HR-feedback. Heart rate, skin conductance (SC), and EMG activity were monitored. Subjects were also requested to indicate the cognitive strategies used during their HR control training. No relationship between heartbeat perception and state-trait anxiety measures was found. The results did not support the idea that individual differences in heartbeat perception are related to individual differences in HR-control. They did indicate, however, that motivating instructions improve the capacity to increase or decrease HR. Subjects were able to voluntarily increase or decrease their HRs with or without a feedback signal. However, more pronounced HR increases were obtained in the feedback as compared with the no-feedback condition. SC and EMG activity were in accordance with arousal levels demanded by HR decrease and increase tasks. Subjects used cognitive strategies concerning activation responses during HR-increase and relaxation responses during HR-decrease conditions.