Robert Edelberg

Heart rate variability biofeedback increases baroreflex gain and peak expiratory flow.

Objective We evaluated heart rate variability biofeedback as a method for increasing vagal baroreflex gain and improving pulmonary function among 54 healthy adults. Methods We compared 10 sessions of biofeedback training with an uninstructed control. Cognitive and physiological effects were measured in four of the sessions. Results We found acute increases in low-frequency and total spectrum heart rate variability, and in vagal baroreflex gain, correlated with slow breathing during biofeedback periods. Increased baseline baroreflex gain also occurred across sessions in the biofeedback group, independent of respiratory changes, and peak expiratory flow increased in this group, independently of cardiovascular changes. Biofeedback was accompanied by fewer adverse relaxation side effects than the control condition. Conclusions Heart rate variability biofeedback had strong long-term influences on resting baroreflex gain and pulmonary function. It should be examined as a method for treating cardiovascular and pulmonary diseases. Also, this study demonstrates neuroplasticity of the baroreflex.

Impact of stress on objectively recorded menopausal hot flushes and on flush report bias.

The hot flush (or flash) is the most widely reported menopausal symptom. Anecdotal reports suggest that women experience more hot flushes when stressed. Although stress may actually trigger hot flushes, another possibility is that women under stress may be more aware of the physiological changes associated with flushes and, therefore, more likely to report them. The goal of this study was to test these hypotheses by investigating the association between stress and both objective (i.e., physiologically recorded) and subjective hot flushes. Twenty-one postmenopausal women who reported having frequent hot flushes each underwent psychophysiological monitoring during stressful and nonstressful laboratory sessions. Significantly more objective flushes were recorded during the stress session than during the nonstress session. The stress manipulation, however, did not affect subjects propensity to report flushes. These results suggest that the observed association between reported hot flushes and stress is not due to changes in report bias. The physiological mechanisms through which stress may stimulate hot flushes are discussed.

Comparison of finger plethysmograph to ECG in the measurement of heart rate variability

Two experiments compared finger plethysmograph (FP) to electrocardiogram (ECG) in providing accurate heart periods for use in heart rate variability (HRV) calculations. In Experiment 1, simultaneous ECG and FP recordings were taken from 16 healthy subjects at rest. In Experiment 2, 10 additional healthy subjects were recorded at rest and during the Stroop Color-Word Test. In both studies, high correlations were found between FP-derived and ECG-derived band variance for high and low frequency HRV at rest. But, during the Stroop task, correlations were strongly diminished. In addition, under both conditions, HRV measures were significantly higher using the FP signal. Thus, FP may be adequate for determining HRV at rest, but, for experimental use, ECG may still be recommended. Nonetheless, further studies that include test-retest reliability assessment of both data collection techniques are warranted before a more certain determination can be made.

Respiratory Sinus Arrhythmia Versus Neck/Trapezius EMG and Incentive Inspirometry Biofeedback for Asthma: A Pilot Study

This pilot study compared biofeedback to increase respiratory sinus arrhythmia (RSA) with EMG and incentive inspirometry biofeedback in asthmatic adults. A three-group design (Waiting List Control n = 5, RSA biofeedback n = 6, and EMG biofeedback n = 6) was used. Six sessions of training were given in each of the biofeedback groups. In each of three testing sessions, five min. of respiratory resistance and EKG were obtained before and after a 20-min biofeedback session. Additional five-min epochs of data were collected at the beginning and end of the biofeedback period (or, in the control group, self-relaxation). Decreases in respiratory impedance occurred only in the RSA biofeedback group. Traub-Hering-Mayer (THM) waves (.03-.12 Hz) in heart period increased significantly in amplitude during RSA biofeedback. Subjects did not report significantly more relaxation during EMG or RSA biofeedback than during the control condition. However, decreases in pulmonary impedance, across groups, were associated with increases in relaxation. The results are consistent with Vaschillos theory that RSA biofeedback exercises homeostatic autonomic reflex mechanisms through increasing the amplitude of cardiac oscillations. However, deep breathing during RSA biofeedback is a possible alternate explanation.

Relationship of resting blood pressure and heart rate to Experienced Anger and Expressed Anger

&NA; Forty‐five nonmedicated subjects rated on analog scales the anger they experienced at home and at work (Experienced Anger). They also rated the extent to which others were aware of their anger (Expressed Anger) and the extent to which anger had been expressed in their families or origin (Family Expressed Anger). They were then physiologically monitored during a 2‐min relaxation period that followed habituation to the laboratory setting. For the group as a whole, Expressed Anger was inversely related to systolic (SBP) and diastolic (DBP) blood pressure while Family Expressed Anger was inversely related to SBP only. When the sample was divided into normotensive and hypertensive subgroups, the normotensives showed significant associations between Experienced Anger and SBP, Expressed Anger and DBP, and Family Expressed Anger and SBP. The hypertensive subgroup showed no significant associations. Both males and females showed a significant association between Expressed Anger and DBP, but only females showed this relationship with SBP. It is concluded that coping with anger by conscious inhibition of its expression is associated with increases in both systolic and diastolic blood pressure.

Cardiac rhythm effects of .125-Hz paced breathing through a resistive load: implications for paced breathing therapy and the polyvagal theory:

This study examined the psychophysiological effects of slow-paced breathing while subjects breathed through external respiratory resistive loads. Twenty-four normal volunteers completed four 5-min trials of paced breathing (.125 Hz) through an inspiratory resistive wire mesh screen (0 to 25 cm H2O/L/s). Each trial was followed by a 5-min rest trial. There was evidence for hyperventilation and/or fatigue during paced breathing. Also, respiratory sinus arrhythmia (RSA) was elevated in the first minute of paced breathing, and then declined toward baseline. Heart period decreased during paced breathing trials, and fell significantly below baseline during rest periods. These data suggest decreased vagus nerve activity and/or sympathetic activation, following an initial increase in parasympathetic activity during paced breathing. They are not consistent with the use of .125-Hz paced breathing as a relaxation technique, particularly during respiratory resistive stress. Finally, although RSA and average heart period changed synchronouslywithin paced breathing and rest conditions, they diverged incomparisons between pacing and rest. This dissociation suggests that different mechanisms mediate these two cardiac parameters. These data are consistent with Porges theory that vagal influences on tonic heart rate are mediated by the combined effect of vagal projections from both the nucleus ambiguus and the dorsal motor nucleus, while RSA is mediated only through the nucleus ambiguus alone.

Relationship of expressed anger to forearm muscle vascular resistance.

The relationship of style of anger expression to physiological reactivity was examined in 45 nonmedicated subjects during their performance of three tasks with contrasting response demands. The primary physiological focus was on forearm muscle vascular resistance (FMVR) with forearm muscle blood flow (FMBF), digital pulse volume (DPV), digital vascular resistance (DVR), heart rate (HR), diastolic blood pressure (DBP), systolic blood pressure (SBP), and electrodermal frequency (EF) monitored. Family Expressed Anger, i.e. the overtness of anger expression in the subjects family of origin, was related to FMVR such that the more anger was expressed in the family of origin, the greater the vasoconstriction during Mental Arithmetic and the less the vasoconstriction during Anger Imagery. Self Expressed Anger, i.e. the degree to which others were aware when the subject was feeling angry, was related to SBP and DBP during Vigilance with a lesser degree of anger expression going with greater blood pressure increases. The meaning of these findings in relation to task appraisal and task demand is discussed.

The paradoxical relation between diastolic blood pressure change under stress and the H factor of the Jenkins activity survey

This study examined the relation of the Type A scale and of the three factors of the Jenkins Activity Survey to the cardiovascular responses of twenty-six subjects during two stressful tasks. The two tasks were reaction time (RT) and paced arithmetic (PA) and the sample was drawn from a general medical practice. While heart rate correlated directly with the subjects score on the Hard Driving and Competitive Factor (H), diastolic blood pressure response to PA was inversely related to the subjects Type A and factor H scores. This paradoxical inverse relation remained highly significant when the diastolic pressure in the rest preceding PA was statistically controlled.

Suppressor effects in the relations of psychological variables to resting blood pressure

The role of suppressor effects in obscuring the relation of psychological variables and blood pressure was studied. Forty-five nonmedicated patients in a family practice rated themselves relative to their peers on a series of characteristics. Two of these, trapped and lonely, exhibited marked suppressor effects in their relationship with each other and resting blood pressure. Self-ratings of lonely exhibited a moderately strong positive association with ratings of trapped (r = .63) while only ratings of lonely showed a significant correlation with resting systolic blood pressure (r = -.31). Yet when the suppressor effects of the ratings on feeling lonely were removed in the regression analyses, the ratings on feeling trapped showed a significant positive association with resting systolic pressure (r =.42). Similarly, while neither ratings on feeling lonely or on feeling trapped showed separately a significant association with resting diastolic pressure, when suppressor effects were removed in the regression analyses, the ratings of trapped were significantly associated with diastolic pressure in a positive direction (r = .34) and ratings of lonely were significantly associated in a negative direction (r = -.33). The significance of this specific suppressor effect and the implications of suppression for psychosomatic research are discussed.