Anxiety, perception, and control of heart rate

8 women and 8 men took Cattell's IPAT-anxiety questionnaire and later McFarland's test of ability to perceive heart activity. The second test involved subjects' tracking their own heart rates, then they enrolled in an EKG biofeedback session to evaluate ability to increase and decrease heart rate from subjects' resting baselines. At the end of the session each subject completed Blanchard, et al.'s questionnaire to specify the cognitive strategies used for heart-rate control. Heart rate, abdominal respiration rate, respiration amplitude, EEG percent power in theta, alpha, and beta bands were evaluated. Success of heart-rate decrease seemed to depend mainly on activity levels: the subjects who achieved high scores on the activity test decreased heart rate significantly better than did low scorers. The relationship between scores for perception of heart and increases in heart rate was nonsignificant: increased heart-rate seemed to depend on differences in respiration between the rest and periods of increase. The significant, negative correlation between trait anxiety and perceptions of heart activity suggested that anxiety affected subjects' ability to perceive heart rate. The theta EEG power of the right hemisphere was significantly higher in subjects scoring high than for those low in perception of heart activity. During heart-rate increase tasks subjects mainly reported use of 'arousal responses,' similarly during heart-rate decrease tasks they reported use of relaxation responses.     

Changes in heart rate during feedback control of respiration

Subjects received one of eight treatments: practice at increasing heart rate with heart-rate feedback, practice at decreasing heart rate with heart-rate feedback, practice at increasing heart rate without heart-rate feedback, practice at decreasing heart rate without heart-rate feedback, practice at increasing respiration rate with respiratory feedback, practice at decreasing respiration rate with respiratory feedback, practice at increasing respiration rate with respiratory instructions only, practice at decreasing respiration rate with respiratory instructions only. Heart rate, Respiration rate, and Respiration depth were measured. Analysis indicated that subjects who controlled respiration with respiratory feedback reliably increased and decreased heart rate; subjects who controlled respiration with respiratory instructions only reliably increased but not decreased heart rate; subjects in the respiratory-feedback conditions showed higher heart-rate increase and decrease than heart-rate increase and decrease of subjects in the other six conditions.     

Autonomic reactivity during viewing of an unpleasant film.

The effect of an aversive, high-arousing film on heart rate, respiratory sinus arrhythmia, and electrogastrographic activity (EGG) was investigated. Previous studies have indicated a larger heart-rate deceleration for visual stimuli depicting surgery or blood compared to neutral content, and this phenomenon is similar to the bradycardia observed in animals in response to fear. The heart-rate deceleration is clearly parasympathetically driven, and it is considered a general index of attention. An accurate index of cardiac vagal tone can be obtained by means of quantification of the amplitude of respiratory sinus arrhythmia. The relationship between cardiac vagal tone and EGG is complex, but animal research has shown that suppressing vagal activity dampens gastric motility. We have investigated whether a movie depicting surgery is associated with greater heart-rate deceleration, larger increase in respiratory sinus arrhythmia, and greater increase in EGG activity compared to a neutral movie. In addition, if both respiratory sinus arrhythmia and EGG are indices of vagal tone, a positive correlation between these physiological responses was expected. Analysis indicated an effect of the surgery movie on heart rate and respiratory sinus arrhythmia, but not on EGG activity. Moreover, the expected correlation was not found. Implications for future studies are discussed.     

Physiological Reactions to a Suicide Film: Suicide Attempters,Suicide Ideators,and Nonsuicidal Patients

A film about two teenagers who commit suicide was shown to three groups of psychiatric inpatients: 17 who had attempted suicide, 20 who had expressed suicidal thoughts, and 10 who were not suicidal. Anxiety before and after the film was evaluated with psychometric (anxiety rating scale) and physiological tools (heart and respiration rate, blood pressure, electromyogram). Values noted before and after screening, and the degree of change in these values, were compared. In addition, psychomotor agitation was rated at several points during the film. Most results were negative. The suicide attempters had significantly lower postscreening heart rates and a significantly lesser change in heart and respiration rates than the other two groups. The suicide attempters revealed an increase in psychomotor agitation until the discovery of the suicide and a decrease thereafter, whereas the agitation of the nonsuicidal patients continued to increase from the start to the end of the film. The study suggests that on some parameters, suicide attempters reveal less anxiety than nonsuicidal psychiatric patients following exposure to a simulated suicide. The reaction of suicide ideators falls somewhere between the two groups.     

Locus of Control and Voluntary Heart-Rate Change

Summary: Investigated the effects of locus of control on voluntary control of heart-rate change. The 32 subjects were randomly assigned to one of two heart-rate change groups: Increase or decrease. The groups were counterbalanced for locus of control and sex. No heart-rate feedback was provided to subjects, and all subjects performed the appropriate task for two sessions. Results indicated that during the initial session, internals were better able to increase their heart-rates than externals; the externals were better able to decrease their heart-rates than internals. This association, however, diminished to nonsignificance in the second session.     

Locus of control and voluntary heart-rate change.

Investigated the effects of locus of control on voluntary control of heart-rate change. The 32 subjects were randomly assigned to one of two heart-rate change groups: Increase or decrease. The groups were counterbalanced for locus of control and sex. No heart-rate feedback was provided to subjects, and all subjects performed the appropriate task for two sessions. Results indicated that during the initial session, internals were better able to increase their heart-rates than externals; the externals were better able to decrease their heart-rates internals. This association, however, diminished to nonsignificance in the second session.     

Effects of incentive and preparatory interval on activity, heart rate, and reaction time in children.

To resolve certain empirical and theoretical difficulties concerning, primarily, the significance of phasic heart-rate deceleration prior to reaction signals, 48 children were employed to perform in simple reaction-time tasks while speed, heart rate, head movement, gross movement, and blink activity were recorded. The indeory intervals and level of incentives. Reaction time varied with incentive, with preparatory interval and mode of presentation. Phasic heart-rate deceleration varied with the intervals but not incentive or mode of presentation. There was little relation between deceleration and RT. Heart rate and somatic movement measures (especially of blinking) were roughly concordant at a group level but did not correlate.     

The effect of increased parasympathetic activity on perceived duration

Theories of human temporal perception suggest that changes in physiological arousal distort the perceived duration of events. Behavioural manipulations of sympathetic nervous system (SNS) activity support this suggestion, however the effects of behavioural manipulations of parasympathetic (PSNS) activity on time perception are unclear. The current study examined the effect of a paced respiration exercise known to increase PSNS activity on sub-second duration estimates. Participants estimated the duration of negatively and neutrally valenced images following a period of normal and paced breathing. PSNS and SNS activity were indexed by high-frequency heart-rate variability and pre-ejection period respectively. Paced breathing increased PSNS activity and reduced the perceived duration of the negative and neutrally valenced stimuli relative to normal breathing. The results show that manipulations of PSNS activity can distort time in the absence of a change in SNS activity. They also suggest that activities which increase PSNS activity may be effective in reducing the perceived duration of short events.     

Effects of single trial of heart-rate biofeedback on the arterial blood pressure, ventilation volume, and oxygen consumption during ramp bicycling exercise

We examined whether the heart rate attenuation resulting from a single trial of biofeedback during exercise occurs without any changes in oxygen consumption (VO2), ventilation volume (V(E)), and mean arterial blood pressure (M(AP)) although these variables are essential determinants for the heart-rate response during exercise. 35 subjects exercised on a cycle ergometer under two conditions while they exercised only (Control) or were trying to decrease the heart-rate response as low as possible by monitoring their own heart-rate responses as Single trial of biofeedback signals. 17 subjects could attenuate their heart rate (Can group), and their heart-rate reduction during Single trial of biofeedback was 5+/-1 bpm. The remaining subjects were unable to reduce heart rate (Cannot group). The heart-rate attenuation during Single trial of biofeedback in the Can group occurred independently of changes in VO2 and MAP but was accompanied by a significant decrease in V(E) and rating of perceived exertion (RPE). However, there was a similar decrease in V(E) in the Cannot group. These findings suggested that the heart-rate attenuation during Single trial of biofeedback was not induced by the metabolic demand of VO2 and the regulations of M(AP) and V(E) during exercise. Other mechanisms, which are probably related to the reduction of RPE, might play an important role in the heart-rate attenuation during a Single trial of biofeedback.     

Conditioned nalorphine-induced abstinence changes: persistence in post morphine-dependent monkeys

Every tenth lever-press of three morphine-dependent rhesus monkeys was reinforced with food. A red light, initially a neutral stimulus, was presented every third or fourth session for 5 min before and 5 min after an intravenous injection of nalorphine, a morphine antagonist that produces an immediate abstinence syndrome in morphine-dependent monkeys. After several pairings, conditioned suppression of lever pressing, heart-rate decrease, vomiting, and excessive salivation were observed during the red-light period before nalorphine injection. No conditioned electrocardiogram, respiration or temperature changes occurred. After 10 red light-nalorphine pairings, morphine administration was completely discontinued and monkeys were then tested monthly for persistence of the conditioned responses. The red light paired with saline injection continued to suppress lever pressing and to produce heart-rate decreases after 60 to 120 days of complete abstinence from morphine. Subsequently, daily presentations of the red light-saline injection complex rapidly extinguished these conditioned responses. Nevertheless, they could be rapidly reinstated by additional nalorphine injections.     

Cardiac activity and information processing: the effects of stimulus significance, and detection and response requirements.

In two experiments, measures of heart rate and electromyographic activity were obtained from 40 male undergraduates while they performed two series of trials involving a sequential information processing task. Each trial consisted of a warning light, three successive tones, and a responded light, separated by 6-sec intervals. In Experiment 1, subjects responded only if the three tones were of different frequencies. Acclerative heart-rate responses to the last tone increased as a function of the significance of that tone. Subsequent cardiac decelerations were only observed if the subject was preparing to make a response. These results were replicated in Experiment 2, in which subjects responded only if two of the preceding tones were of the same frequency. Electromyographic activity was not significantly affected by stimulus significance or response anticipation. The data indicate that cardiac acceleration and deceleration reflect two independent psychological processes, associated with information-processing and decision-making activity on the one hand, and preparatory activity on the other.     

Effects of single trial of heart-rate biofeedback during ramp bicycling exercise

We examined whether a single trial of heart-rate biofeedback was effective to attenuate heart-rate responses during ramp exercise despite a lack of biofeedback conditioning. 35 healthy women exercised in two trials while they tried to attenuate their heart rate by watching biofeedback signals or they only exercised without biofeedback signals (Control trial). 17 subjects were able to attenuate the heart rate during Biofeedback trial (Can group) whereas the remaining subjects were not (Cannot group). In the Can group, the magnitude of heart-rate attenuation in all exercise time was equivalent to 11+/-3% of the preexercise heart rate. Since the heart-rate reduction was similar to that achieved after the heart-rate biofeedback conditioning in previous studies, it is likely that the single trial of heart-rate biofeedback was effective for almost half the subjects to attenuate the heart-rate responses during ramp exercise.     

Postnatal development of respiratory and vocal responses during aversive classical conditioning in cats

Respiratory rate, respiration amplitude, and vocal responses were recorded in cats of different ages during classic conditioning. Vocal responses to the conditional stimulus (CS) appeared first in 8-week-old kittens, and became prominent at older ages. An increase in respiration rate occurred after the onset of the CS in cats of all ages. Similarly, the decrease of respiration amplitude was observed at all ages, but only in 8-week-old and older subjects did this response resemble an adult pattern. In 4-week-old kittens the response was characterized by an early and brief peak, suggesting an alpha conditional response (CR). Clear and significant discrimination between a warning and a safety signal was present in both respiratory and vocal responses after the age of 8 weeks.     

The humour effect: differential processing and privileged retrieval.

The effects of humour on memory and heart rate were explored as a function of experimental design. In within-subject manipulations, original humorous cartoons were better remembered than the literal translations and weird cartoons, whereas literal and weird cartoons were equally well remembered. Good recall of humorous cartoons occurred at the expense of recall of non-humorous cartoons. Secondary heart-rate deceleration was larger in response to original cartoons than to literal and weird cartoons. Neither the memory nor the heart-rate effects were found in between-subjects comparisons. The results were consistent with differential processing resulting from within-list contrasts. However, retrieval processes also favoured good recall of humorous material.     

Effects of an emotional negative stimulus on the cardiac, electrogastrographic, and respiratory responses

The experiment investigated the effects of two film sequences, one neutral and the other emotional, on the cardiac (ECG), electrogastrographic (EGG) and respiratory activities of 24 healthy students during digestion. The physiological activity was recorded before and during the projection of each film sequence. 12 subjects were shown a neutral film sequence and 12 an emotional film sequence. At the end of each viewing period, each subject completed a self-rating questionnaire on the emotional experience. Analysis indicated, with respect to the previewing (baseline) values, an increase in cardiac and respiratory rates and a decrease in electrogastrographic rates during the viewing of the film sequences. Changes in the EGG rate (baseline to viewing) were negatively correlated with the changes in ECG and respiratory rates, whereas the changes in these latter two were positively correlated. In comparing the effects of the neutral and emotional scenes the only significant result was the heart-rate increase in subjects watching the emotional sequence. Also, the self-rating of emotional experience varied with the emotional value of the sequence.     

Individual differences in delayed heart-rate recovery following stress: The role of extraversion,neuroticism and emotional control

The aim of this study was to investigate the effects of individual differences on heart-rate reactivity and recovery following exposure to a laboratory stressor (performance on the Stroop task). The personality scales used were EPI Extraversion and Neuroticism and four subscales comprising the Emotion Control Questionnaire (ECQ). Contrary to predictions the EPI scales were unrelated to the physiological indices, but there were significant correlations between the Benign Control scale of the ECQ and heart rate reactivity and between the Rehearsal scale and heart-rate recovery.     

Effects of short-term psychological stress on the time and frequency domains of heart-rate variability

The purpose of this study was to test the hypothesis that short-term psychological stress produces significant changes in sympathovagal activity. A simple, noninvasive method was used measuring the timing and frequency of heart-rate variability (HRV). 30 normal healthy subjects were assigned into two age- and sex matched groups. In the experimental condition a 5-min. psychological stress test, predominantly based on the Stroop Word Color Conflict Test, was employed in a competitive setting and included a financial inducement to produce psychological strain. Analysis showed that during psychological stress a significant reduction in the timing and frequency of heart rate variability was observed. The standard deviation of interbeat intervals decreased. A significant increase in heart rate was also observed. Within the frequency domain, a significant reduction in the high frequency component of HRV and a significant increase in the low frequency component were observed. There was also a significant increase in the low frequency to high frequency ratio. Self-evaluation of physical tension and emotional state measured by visual analog scales also showed significant increases following psychological stress. No significant differences were observed on any variables within the control group. The results indicate a shift towards sympathetic predominance as a result of parasympathetic withdrawal and demonstrates that this psychological stress test is effective in provoking a characteristic defence-arousal reaction. This simple, cost-effective method of analysing heart rate variability is suitable for detection of short-term changes in sympathovagal balance.     

Effect of pedal rate and power output on rating of perceived exertion during cycle ergometry exercise

This study examined differentiated rating of perceived exertion (RPE), heart rate, and heart-rate variability during light cycle ergometry exercise at two different pedal rates. 30 healthy men (22.6 +/- 0.9 yr.) were recruited from a student population and completed a continuous 20-min. cycle ergometry exercise protocol, consisting of a 4-min. warm-up (60 rev./min., 30 Watts), followed by four bouts of 4 min. at different combinations of pedal rate (40 or 80 rev./min.) and power output (40 or 80 Watts). The order of the four combinations was counterbalanced across participants. Heart rate was measured using a polar heart-rate monitor, and parasympathetic balance was assessed through time series analysis of heart-rate variability. Measures were compared using a 2 (pedal rate) x 2 (power output) repeated-measures analysis of variance. RPE was significantly greater (p<.05) at 80 versus 40 rev./min. at 40 W. For both power outputs heart rate was significantly increased, and the high frequency component of heart-rate variability was significantly reduced at 80 compared with 40 rev./min. These findings indicate the RPE was greater at higher than at lower pedalling rates for a light absolute power output which contrasts with previous findings based on use of higher power output. Also, pedal rate had a significant effect on heart rate and heart-rate variability at constant power output.     

Fear of negative evaluation augments negative affect and somatic symptoms in social-evaluative situations

The aim of this study was to determine whether fear of negative evaluation (FNE) moderates effects of eye contact on mood, bodily symptoms and physiological activity during social-evaluative situations. Facial blood flow, skin conductance, heart rate and respiration rate were recorded in 42 participants while they sang a children's song, while they were observed or made direct eye contact with the experimenter, and while they listened to an audiotape of themselves singing. Physiological responses were similar in high and low FNE groups. However, differences lay in the perception of bodily symptoms and ratings of negative affect, with the high FNE group reporting greater ratings. In addition, prior eye contact enhanced the perception of bodily symptoms in the high FNE group when they listened to the audiotape. Concern about the social consequences of displaying bodily disturbances such as trembling, blushing and sweating may explain these findings.     

Age-related changes in cardiovascular response as a function of a chronic stressor and social support.

The effects of aging, chronic stress, and social support on cardiovascular functioning were examined using a cross-sectional design. Thirty-six family caregivers of Alzheimer's disease victims and 34 control Ss performed 2 active coping tasks while continuous noninvasive measures of cardiovascular activity were monitored. Results revealed that caregivers high in social support displayed typical age-related decreases in heart-rate reactivity, whereas caregivers low in social support displayed age-related increases in heart-rate reactivity. Analyses further indicated that only Ss with low social support were characterized by age-related increases in systolic blood pressure. These results suggest that social support can moderate age-related changes in cardiovascular functioning, particularly in Ss exposed to a chronic stressor.