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.     

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.     

The Impact of Biofeedback-Manipulated Physiological Change on Emotional State

In the present study, subjects were administered 16 biofeedback sessions, during which they were trained to significantly increase and decrease their heart rates. Before and immediately following each biofeedback training session, state anxiety was evaluated in subjects by use of the State-Trait Anxiety Inventory. Results indicated that heart-rate slowing performance was associated with a significant decrease in state anxiety; heart-rate speeding performance was associated with an increase in state anxiety. The implications of these findings for further investigation of theories of emotion, and the role played by physiological arousal, are discussed.     

Anxiety and heart rate under psychological stress: The effects of exercise-training

Abstract The effects of a 12-week exercise-training program on cognitive, somatic, and behavioral anxiety and on heart rate responses to evaluative stress were scrutinized in 89 subjects randomly assigned to an experimental (exercise) or a control group. The training program consisted of exercises that were aimed to the improvement of the general physical fitness (i.e., strength, flexibility, and endurance). Following the 12-week training period, exercising subjects showed improved motor skill capacity as well as higher VO(2) max. In an anxiety inciting test situation, that consisted of the video-taped delivery of a 5-min speech, a mental arithmetic and a fine motor task, exercising subjects showed more favourable responses than control subjects in three ways: (a) they exhibited lower behavioral anxiety during the anticipation phase of the three stressors, (b) they reported lower cognitive and somatic anxiety during the anxiety provoking situation, and (c) their heart rate recovered faster, in contrast to both their baseline heart rate and the control subjects' heart rate, from the stress episode. These results demonstrate that a fitness-oriented exercise program has anxiolytic properties. They also provide a primary evidence that overt behavioral anxiety, as opposed to the usually measured self-reported anxiety, may be affected by exercise.     

Acute effects of aerobic exercise on mood

Thirty-two female students participated in a single-session experiment during which they carried out two 8-min trials of high-intensity exercise and two 8-min trials of low-intensity exercise. One high- and one low-exercise trial were accompanied by music; the other two trials were accompanied by metronome. Mood was assessed with a modification of the Profile of Mood States before and immediately after each trial. The purpose of the experiment was disguised to reduce the influence of subject expectations on mood responses. Participants were divided into fit and unfit groups based on heart rate responses during high-exercise trials. Overall, high-intensity exercise led to increases in tension/anxiety and fatigue, whereas positive mood changes (vigor and exhilaration) were seen following low-intensity exercise only. No group differences in mood responses were observed. Explanations of these results are considered in light of other literature concerning the acute effects of exercise on mood.     

The effect of short duration heart rate variability (HRV) biofeedback on cognitive performance during laboratory induced cognitive stress

The aim of this study was to examine the effect of 10 minutes of heart rate variability (HRV) biofeedback on cognitive performance and affect scores during induced stress. Eighteen healthy male volunteers (aged 23–41 years) exposed to work‐related stress, were randomised into an HRV biofeedback intervention (BIO) and a comparative intervention group (COM). Subjects completed a modified Stroop task, which included having to mentally count 18 white squares randomly presented between colour words, before and after a 10‐minute intervention. Subjects also completed questionnaires to rate their anxiety. BIO subjects improved their reaction times and consistency of responses, and made fewer mistakes in counting squares during the modified Stroop task. They also felt more relaxed, less anxious and less sleepy than the COM subjects. In conclusion our results suggest that short duration HRV biofeedback is associated with improved cognitive performance while concurrently aiding relaxation. Copyright © 2010 John Wiley & Sons, Ltd.     

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.     

Effects of instructions, biofeedback, reward, and cognitive mediation on the control of heart rate and the application of that control in a stressful situation

Subjects in Phase 1 of this experiment were (a) instructed to try to either increase or decrease their heart rate, (b) with or without the use of biofeedback, and (c) with or without the promise of money for successful performance, whereas no-treatment subjects were given no instructions, no biofeedback, and no promise of reward. Results indicated that (a) when simply instructed to do so, subjects could increase but not decrease their heart rates relative to no treatment controls, (b) the promise of money for good performance aided subjects in increasing but not decreasing heart rate, and (c) biofeedback did not aid subjects in either increasing or decreasing heart rate. Various cognitive strategies employed by subjects in controlling their heart rates are discussed.In Phase 2, subjects in a stress condition were told that they would receive a series of painful electric shocks, whereas subjects in a no stress condition were not told about shocks. All subjects were instructed to try to decrease their heart rates during the “shock” period. Heart rate and self report data revealed that (a) the manipulation was successful in increasing stress, and (b) previous training in decreasing heart rate, with or without biofeedback, did not aid subjects in decreasing their heart rates in the face of the stress.     

Reaction time task as unconditional stimulus

Nonaversive unconditional stimuli (USs) are seldom used in human classic conditioning of autonomic responses. One major objection to their use is that they produce deficits in electrodermal (ED) second- and third-interval response conditioning. However, a nonaversive reaction time (RT) task that includes feedback of success has been shown to be an effective US while avoiding this disadvantage (Lipp and Vaitl 1988). The present study compared this new RT task (RT-new) with a traditional RT task (RT-old) and with a standard aversive US (shock) in differential classic conditioning of ED, heart rate (HR), and digital pulse volume (DPV) responses. Eight-second-delay differential conditioning was applied in three groups of 12 subjects each. Simple geometric features (square, cross) displayed on a television screen served as conditional stimuli (CS⁺ and CS^?). In acquisition, there were no statistically significant differences among the groups; differential conditioning did occur in HR, first- and second-interval ED responses, and first-interval DPV responses. Separate analyses within each group, however, revealed that there was no second-interval ED conditioning in the RT-old group. During extinction, neither DPV nor second-interval ED conditioning could be obtained, whereas HR and first-interval ED conditioning occurred in each group. In third-interval omission ED responses, RT-old and shock groups exhibited extinction, while response differentiation was maintained in the RT-new group throughout extinction. The RT task including feedback proved to be as reliable a US as a standard aversive US, whereas application of a traditional RT task again yielded some weaknesses in second-interval ED conditioning.     

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.     

Does self-efficacy moderate intensity of pain?

75 subjects were randomly assigned to five self-efficacy conditions (High-High, High-Low, Low-High, Low-Low, and Control) in a 5 x 3 (condition x trial) design. Pressure was applied three times to an exposed finger. After baseline, subjects received false biofeedback (i.e., independent of ratings of pain) that their ability to regulate intensity of pain was either good (High-High and High-Low) or poor (Low-High and Low-Low), or there was no biofeedback (Control). After a second trial, subjects were told that their biofeedback indicated either good (High-High and Low-High) or poor (High-Low and Low-Low) regulatory ability, or they were not given biofeedback (Control). They then received a final trial. Before each trial, subjects recorded self-efficacy expectations for regulating intensity of pain. Mixed multivariate analyses of variance on ratings of intensity and self-efficacy expectations did not yield hypothesized interactions for condition x trial.     

Aerobic cycle exercising in a rehabilitation program with a wider choice of intensity

When patients in rehabilitation programs use cycle ergometers for aerobic fitness training, the exercise intensity is often restricted to a small range of heart rate. In this study, a wider choice of intensities was left to the patients without giving up the potential to reduce cardiac risks factors. 24 patients in 3-wk. rehabilitation programs could choose the exercise intensity up to a workload limit preset by the physical therapist. 20 of them exercised at an intensity covering the full range between the aerobic and anaerobic lactate threshold and 4 a little above. The opportunity to vary the workload was frequently used by 67%. In 75% of the exercise sessions, the patients' average heart rates exceeded moderate heart-rate targets recommended in rehabilitation and health promotion for people with moderate cardiac risks without a graded exercise test. In 72% of these sessions, the anaerobic lactate threshold at 4 mmol/L was not exceeded. But a tendency of 33% of the patients to exercise at higher blood lactate or blood pressure levels underlined the necessity of limiting the exercise intensity.     

The effect of choice of exercise mode on psychological responses

Objectives: Choice has been linked to both motivation and psychological responses to exercise. This paper investigates participants’ psychological responses when they completed an exercise session where there was a high-preference exercise mode as opposed to a low-preference exercise mode. High- and low-preference were established by participants indicating their preferred choice of exercise from three standard modes used for aerobic work.Method: Participants were 20 low-active adults who exercised for 20 min on each mode of exercise (high-preference versus low-preference). Affect, ratings of perceived exertion (RPE) and heart rate (HR) were recorded every 5 min during exercise, and affect and HR were assessed pre-exercise and 5 min post-exercise.Results: Repeated measures analysis of variance revealed condition and time main effects for affect sub-scales and RPE and a time main effect for HR. Affect sub-scales, RPE and HR generally increased over time. RPE, Fatigue and Psychological Distress were higher in the low-preference condition and positive well-being was higher in the high-preference condition.Conclusions: Affect and RPE were influenced by the preferred choice manipulation. Affect was more positive, and RPE lower, in the high-preference versus low-preference condition while work rate remained constant across conditions.     

Triadic consistency and false heart-rate feedback

Subjects viewed slides of the Rorschach cards while listening to heart sounds that were supposedly but not actually their own. For some of the subjects the heart rate increased when they were exposed to the five achromatic cards and for some subjects the heart rate increased when they were exposed to the five chromatic cards. In addition, some subjects were told that increased heart rate was a sign of mental health (positive condition), and some that the increased heart rate was a sign of mental abnormality (negative condition) Since the heart-rate increase (behavior) and Rorschach cards associated with the increase (attitude object) are connected by a positive causal relation, triadic theory predicts that the sign of the heart-rate increase should generalize to the associated cards (i e, be positive in the positive condition and negative in the negative condition) An analysis of variance revealed such an overall significant effect Closer examination of the data, however, revealed that the triadic effects were not unambiguously occurring when the increased heart rate was associated with achromatic cards It was suggested that in this condition the unique characteristics of the cards facilitated the generation of complicating anxiety. Supportive data for this interpretation were offered     

The effect of unilateral stellectomy on the regulation of heart rate during behavioral stress.

Changes in heart rate were examined during classical aversive conditioning before and after either left (n = 10) or right stellectomy (n = 8). Heart rate (HR) significantly (p less than 0.01) increased in response to the conditional stimulus with a further increase noted during the unconditional stimulus. After right stellectomy (RSGx) the aversive stress elicited a significantly (p less than 0.01) smaller increase in heart rate (peak HR change: control 66.8 +/- 6.0; RSGx 36.1 +/- 6.8 beats/min). In contrast left stellectomy did not significantly alter the heart rate conditional response. Cardioselective beta-adrenergic receptor blockade, metoprolol HC1 (BB, 1.0 mg/kg, n = 8), significantly (p less than 0.01) reduced the heart-rate conditional response (peak HR change: control 66.8 +/- 6; BB 25.1 +/- 3.8 beats/min) to the same extent as noted during RSGx. These data suggest that the heart-rate increases elicited by aversive stress are mediated in part by sympathetic nerves that originate or pass through the right stellate ganglion. The residual HR increase noted after RSGx or BB probably results from the withdrawal of cardiac parasympathetic activity.     

The effect of unilateral stellectomy on the regulation of heart rate during behavioral stress

Changes in heart rate were examined during classical aversive conditioning before and after either left (n=10) or right stellectomy (n=8). Heart rate (HR) significantly (p<0.01) increased in response to the conditional stimulus with a further increase noted during the unconditional stimulus. After right stellectomy (RSGx) the aversive stress elicited a significantly (p<0.01) smaller increase in heart rate (peak HR change: control 66.8 +/- 6.0; RSGx 36.1 +/- 6.8 beats/min). In contrast left stellectomy did not significantly alter the heart rate conditional response. Cardioselective beta-adrenergic receptor blockade, metoprolol HCl (BB, 1.0 mg/kg, n=8), significantly (p<0.01) reduced the heart-rate conditional response (peak HR change: control 66.8 +/- 6; BB 25.1 +/- 3.8 beats/min) to the same extent as noted during RSGx. These data suggest that the heart-rate increases elicited by aversive stress are mediated in part by sympathetic nerves that originate or pass through the right stellate ganglion. The residual HR increase noted after RSGx or BB probably results from the withdrawal of cardiac parasympathetic activity.     

Effects of instructions and biofeedback on EEG-alpha production and the effects of EEG-alpha biofeedback training for controlling arousal in a subsequent stressful situation

In Phase One, 44 subjects participated in a 2 (instructions to increase alpha, no instructions to increase alpha) × 2 (alpha biofeedback, no alpha biofeedback) factorial experiment. Results indicated that increases in alpha production were due to instructions to increase alpha and that biofeedback had no effect on alpha production. In Phase Two, the 44 subjects from Phase One were exposed to a threat of shock whereas 11 additional subjects in a control condition were not. The design employed in Phase Two was a 2 (previous instructions and stress, no previous instructions and stress) × 2 (previous biofeedback and stress, no previous biofeedback and stress) plus 1 (no previous instructions/no previous biofeedback, no stress). Results indicated that the threat of shock was effective in increasing arousal (as measured by heart rate and skin resistance) but previous EEG-alpha biofeedback training was not effective in helping subjects decrease arousal while in the stressful situation. The results indicate that it is the instructions (and related information concerning alpha) rather than the biofeedback that is critical in alpha biofeedback training and that this training does not appear to have utility for controlling arousal under stress.     

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.     

Awareness of the response after feedback training for changes in heart rate and sudomotor laterality

What is the relation between the ability to control visceral responding on a biofeedback task and the ability to report behaviors actually contributing to this performance? Subjects received biofeedback training for unidentified visceral responses and then gave written reports about what they had done to control the feedback displays. Independent judges were given these reports and, on the basis of knowledge about activities known to contribute to visceral activity, were asked to determine the visceral responses for which the subjects had been trained. The reports of subjects who succeeded at bidirectional control of heart rate (Experiment 1) or sudomotor laterality (Experiment 2) showed awareness of behaviors related to feedback as assessed by this procedure, whereas the reports of subjects who failed at bidirectional control did not. Subsequent experiments indicated that these results did not depend on a learning strategy that might have been specific to the initial studies. These findings call into question the view that people are unaware of what they have done to produce the response after training on biofeedback tasks. Earlier studies reporting lack of awareness in biofeedback are discussed in light of factors that affect the measurement of biofeedback learning and response awareness.     

The Effects of Physical Conditioning on selected Dimensions of Self Concept in Sedentary Females

Occupational therapists treat a large number of clients who maintain inactive lifestyles and who exhibit physical as well as psychological impairments. While a link is widely accepted betwcen physical and mental health, research in this area is equivocal. The present study was designed to test the hypothesis that physical conditioning improves self-concept and body-satisfaction. The Tennessee Self Concept Scale (TSCS) and the Body-Cathexis Scale (BCS) were administered before and after a physical training program to sedentary females. The subjects, ranging from 23-41 years of age, underwent exercise tests, were matched by age, weight, and fitness level and randomly assigned to arm-training, leg-training or control groups. The conditioning groups exercised on cycle ergometers for 6 weeks while the control group refrained from exercise. Analyses of variance conducted on three subcales of the TSCS and on the BCS revealed groups X trials interactions that were significant for the physical self and self-satisfaction subscales and nearly significant for the BCS. Changcs in the pcrsonal self subscale wcre nonsignificant. A significant correlation was found between physical self and body-cathexis but not between changcs in mean heart rate or maximum workload tolerated and changcs in physical self. The study substantiates the hypothesis that psychological gains are most apparent in people who are physically unfit, and suggests that participation in an aerobic conditioning program has psychological benefits for sedentary individuals.