Biofeedback-aided relaxation and meditation in the management of hypertension

Based on clinical, epidemiological, and experimental work, a possible pathogenesis of essential hypertension is outlined. In the light of this possible pathogenesis, a behavioral treatment program is suggested which centers on the regular use of systematic relaxation training. Several controlled studies are described in which experimental patients given such training show clinically significant and lasting reductions in systolic and diastolic pressure. Following training, experimental patients also show quicker recovery of blood pressures to baseline levels after exposure to standardized laboratory stressors. Probable long-term benefits of relaxation training are suggested. Such benefits, however, can only be maintained if the patient regularly practices relaxation and integrates this into his everyday activities. How to motivate symptomless hypertensives to accept this requirement is discussed in the light of the writer's personal experience.     

Effectiveness of multiple muscle-site EMG biofeedback and relaxation training in reducing the aversiveness of cancer chemotherapy

A 44-year-old female cancer patient was given progressive muscle relaxation training and multiple muscle-site EMG biofeedback to reduce the conditioned negative responses she had apparently developed to her chemotherapy treatments. Following three baseline chemotherapy sessions, the patient was given relaxation training and biofeedback during four consecutive chemotherapy treatments and was asked to practice her relaxation skills daily in the hospital or at home. After the patient felt able to relax on her own, relaxation training and biofeedback were terminated and three follow-up sessions were held. Results indicated that during the chemotherapy sessions in which the patient received relaxation training and biofeedback, she showed reductions in physiological arousal (EMG, pulse rate, systolic blood pressure, and diastolic blood pressure) and reported feeling less anxious and nauseated. Moreover, these changes were maintained during the follow-up sessions. These results suggest that relaxation training plus multiple muscle-site biofeedback may be an effective adjunctive procedure for reducing some of the adverse side effects of cancer chemotherapy.     

Racial and gender effects on the relaxation response: Implications for the development of hypertension

This study was designed to explore the effect of race and gender on the forehead muscle tension and finger temperature response to biofeedback-assisted relaxation training in individuals with normal blood pressure. Forty-five subjects—18 Black and 27 White, 25 males and 20 females—participated in eight sessions of autogenic relaxation training and thermal biofeedback. Multivariate analysis of variance of the variables measured at baseline (systolic BP, diastolic BP, sodium excretion, anxiety) was significant for gender. Univariate analysis showed males different from females in DBP, Na⁺ excretion, and trait anxiety. Pretest values of muscle tension were similar by gender, but pretest temperatures were lower in males than females. Repeated measures ANOVA for muscle tension showed a significant effect of period. For temperature, a significant effect of period, gender, and gender × period was observed. Males increased temperature more than females. There was no effect of history of hypertension on the relaxation response. Multiple regression performed on change in muscle tension and change in temperature showed that pretest muscle tension predicted change in muscle tension. Four variables contributed to the variance in change in temperature: pretest temperature, sodium excretion, and state and trait anxiety.     

Reduction of blood pressure by indirect biofeedback

Forty-five randomly assigned subjects served in either a relaxation control, an EMG plus thermal, or a thermal biofeedback group. All groups received the same relaxation manipulation. Experimental results demonstrated a significant drop in both diastolic and systolic blood pressure for the feedback treatment. Diastolic measures showed a somewhat greater decrease for the EMG plus thermal treatment condition. A learning effect was demonstrated both within and across the three experimental sessions. Given that the sample was normotensive, the 20% reduction in blood pressure was notable. The results support the idea that blood pressure biofeedback is not a necessary condition for reduction of arterial blood pressure.     

Influence of rest interval lengths on hypotensive response after strength training sessions performed by older men

The purpose of this study was to compare the postexercise hypotensive response after different rest intervals between sets (1 and 2 minutes) in normotense older men. Seventeen older men (67.6 ± 2.2 years) with at least 1 year of strength training experience participated. After determination of 10 repetition maximum (10RM) loads for exercises, subjects performed 2 different strength training sessions. On the first day, volunteers performed 3 sets of 10 repetitions per exercise at 70% 10RM, with 1 or 2 minutes' rest interval between sets depending on random assignment. On the second day, the procedures were similar but with the other rest interval. There was no difference in systolic and diastolic blood pressure between rest intervals at any time point measure. Before 1- and 2-minute sessions, the systolic blood pressure values were 122.7 ± 6.0 and 123.2 ± 3.7 mm Hg, and diastolic blood pressure values were 80.5 ± 5.6 and 82.0 ± 3.7 mm Hg, respectively. Both 1 and 2 minute sessions still presented reduced values for systolic blood pressure after 60 minutes (102.9 ± 6.9 and 106.7 ± 5.4 mm Hg, respectively), while the diastolic blood pressure presented significant reductions for 50 minutes after a 1 minute session (12.1 to 5.6 mm Hg) and for 60 minutes after the 2 minute session (13.3 to 6.5 mm Hg). Additionally, the systolic and diastolic blood pressure effect size data demonstrated higher magnitudes at all time point measures after the 2-minute rest sessions. These results suggest a poststrength training hypotensive response for both training sessions in normotense older men, with higher magnitudes for the 2-minute rest session. Our findings suggest a potentially positive health benefit of strength training.     

Sympathetic adrenergic blockade effects upon operantly conditioned blood pressure elevations in baboons

Sympathetic adrenergic nervous activity during operantly conditioned hypertension was evaluated by assessing the effects of specific alpha-(phentolamine or phenoxybenzamine) and beta- (propranolol) adrenergic blockers in baboons reinforced for increasing diastolic pressure in daily, 12-h sessions. In the first 10 min of control (no blockade) sessions, mean heart rate increased 24 bpm (21%) above the value for the 10 min immediately prior to the beginning of the sessions; systolic pressure increased 27 mm Hg (22%) and diastolic pressure increased 24 mm Hg (31%). Betablockade eliminated the tachycardia but did not attenuate the increased blood pressure. Alpha-blockade did not attenuate the increased blood pressure significantly either. Combined alpha- and beta-blockade did significantly attenuate the increase in diastolic pressure, but consistent, significant increases in systolic pressure (17 mm Hg, 17%) and diastolic pressure (16 mm Hg, 26%) still occurred. The results support the participation of the sympathetic adrenergic nervous system in producing operantly conditioned blood pressure changes, but the results are also consistent with the additional participation of nonadrenergic factors in operantly conditioned hypertension.     

Physiological responses during meditation and rest

Forty nonmeditators and 12 experienced transcendental meditators were randomly assigned to four experimental cells devised to control for order and expectation effects. All 52 (female) subjects were continuously monitored on seven physiological measures during both meditation and rest. Each subject was her own control in an abab experimental paradigm comparing meditation to rest. Analyses of variance on change scores calculated from both initial and running (intertrial) baselines revealed small but significant conditions effects for all variables except diastolic BP. The same subjects (both experienced meditators and those meditating for the first time) showed lower psychophysiological arousal during the meditation than during the rest condition for systolic BP, HR, SCL, digital BV, digital ST, and frontalis EMG. The experienced meditators showed only marginally more conditions effects than the novices practicing "noncultic" meditation. For the nonmeditators, deliberately fostering positive expectations of meditations was associated with lower physiological arousal in terms of diastolic BP, HR, and SCL. These findings suggest that both cultic and noncultic meditation are associated with lower physiological activation than eyes-closed rest. The meditators, however, tended to become more relaxed over meditation trials, whereas the nonmeditators showed the opposite trend.     

Low-density lipoprotein receptor-related protein 5 variant A1330V is a determinant of blood pressure in Japanese males

We examined the influence of the A1330V variant in the low-density lipoprotein receptor-related protein 5 gene on blood pressure in a large cohort of Japanese workers. This study used analysis of covariance in a multivariate general linear model to adjust for other potential factors such as age, body mass index, blood chemistry and lifestyle. The target subjects were 1440 males and 1169 females selected from 3834 male and 2591 female workers in a single company. Hypertension was defined as systolic blood pressure >or=140 mm Hg and/or diastolic blood pressure >or=90 mm Hg or the use of antihypertensive medications. Genotype distributions for A1330V in hypertensive males (AA=139(54.5%), AV=101(39.6%), VV=15(5.9%)) and females (AA=48(63.2%), AV=24(31.6%), VV=4(5.3%)) were not significantly different from normotensive males (AA=594(50.1%), AV=488(41.2%), VV=103(8.7%)) and females (AA=568(52.0%), AV=441(40.3%), VV=84(7.7%)). Allele distributions were not significantly different in either sex. In males, analysis of covariance showed that the VV genotype was associated with a 2.5 mm Hg lower diastolic blood pressure and a 2.3 mm Hg lower mean blood pressure than the AA genotype. This study indicates that the 1330V allele is an independent factor for lower diastolic and mean blood pressure in Japanese males.     

The relative effectiveness of three techniques to induce the trophotropic response.

The purpose of this study was to examine the relative effectiveness of electromyographic biofeedback training (EMG BFT), meditation, and progressive muscle relaxation (PMR) in eliciting a relaxation or trophotropic response as measured by frontalis muscle tension, heart rate, electrodermal response, respiration rate, and skin temperature. Fifty-four college students were randomly assigned to one of five groups: (1) control, (2) placebo control, (3) EMG BFT, (4) meditation, (5) PMR. After baseline measures were obtained subjects were trained in 10 30-minute training sessions and posttested. Comparisons by ANOVAs indicated there was a significant decrease in muscle tension in the EMG BFT and meditation groups and significant decreases in respiration rate in the meditation and PMR groups. No other changes were attributed to treatment.     

Biofeedback of R-wave-to-pulse interval normalizes blood pressure

We investigated whether biofeedback of the R-wave-to-pulse interval, a measure related to the pulse wave velocity, enables participants with either high or low arterial blood pressure to modify their blood pressure. Twelve participants with high blood pressure (mean systolic blood pressure = 142.6 ± 13.5 mmHg; mean diastolic blood pressure = 99.9 ± 12.3 mmHg) and 10 participants with low blood pressure (mean systolic blood pressure = 104.8 ± 6.6 mmHg; mean diastolic blood pressure = 73.2 ± 4.2 mmHg) received 3 individual sessions of RPI biofeedback within a 2-week period. Participants with high blood pressure were rewarded for decreasing and participants with low blood pressure for increasing their blood pressure. Standard arm-cuff blood pressure measurements across the sessions served as dependent variables. Participants with high blood pressure achieved significant reductions of systolic (15.3 mmHg) and diastolic (17.8 mmHg) blood pressure levels from the beginning of the first to the end of the last training session. In contrast, participants with low blood pressure achieved significant increases in systolic (12.3 mmHg) and diastolic (8.4 mmHg) blood pressure levels. The degree of blood pressure changes in this study might be of clinical relevance. With prolonged and refined training regimens, even larger effects seem to be likely.     

Physiological responses during meditation and rest

Forty nonmeditators and 12 experienced transcendental meditators were randomly assigned to four experimental cells devised to control for order and expectation effects. All 52 (female) subjects were continuously monitored on seven physiological measures during both meditation and rest. Each subject was her own control in an abab experimental paradigm comparing meditation to rest. Analyses of variance on change scores calculated from both initial and running (intertrial) baselines revealed small but significant conditions effects for all variables except diastolic BP. The same subjects (both experienced meditators and those meditating for the first time) showed lower psychophysiological arousal during the meditation than during the rest condition for systolic BP, HR, SCL, digital BV, digital ST, and frontalis EMG. The experienced meditators showed only marginally more conditions effects than the novices practicing noncultic meditation. For the nonmeditators, deliberately fostering positive expectations of meditations was associated with lower physiological arousal in terms of diastolic BP, HR, and SCL. These findings suggest that both cultic and noncultic meditation are associated with lower physiological activation than eyes-closed rest. The meditators, however, tended to become more relaxed over meditation trials, whereas the nonmeditators showed the opposite trend.     

Overweight female rats selectively breed for low aerobic capacity exhibit increased myocardial fibrosis and diastolic dysfunction

The statistical association between endurance exercise capacity and cardiovascular disease suggests that impaired aerobic metabolism underlies the cardiovascular disease risk in men and women. To explore this connection, we applied divergent artificial selection in rats to develop low-capacity runner (LCR) and high-capacity runner (HCR) rats and found that disease risks segregated strongly with low running capacity. Here, we tested if inborn low aerobic capacity promotes differential sex-related cardiovascular effects. Compared with HCR males (HCR-M), LCR males (LCR-M) were overweight by 34% and had heavier retroperitoneal, epididymal, and omental fat pads; LCR females (LCR-F) were 20% heavier than HCR females (HCR-F), and their retroperitoneal, but not perireproductive or omental, fat pads were heavier as well. Unlike HCR-M, blood pressure was elevated in LCR-M, and this was accompanied by left ventricular (LV) hypertrophy. Like HCR-F, LCR-F exhibited normal blood pressure and LV weight as well as increased spontaneous cage activity compared with males. Despite normal blood pressures, LCR-F exhibited increased myocardial interstitial fibrosis and diastolic dysfunction, as indicated by increased LV stiffness, a decrease in the initial filling rate, and an increase in diastolic relaxation time. Although females exhibited increased arterial stiffness, ejection fraction was normal. Increased interstitial fibrosis and diastolic dysfunction in LCR-F was accompanied by the lowest protein levels of phosphorylated AMP-actived protein kinase [phospho-AMPK (Thr(172))] and silent information regulator 1. Thus, the combination of risk factors, including female sex, intrinsic low aerobic capacity, and overweightness, promote myocardial stiffness/fibrosis sufficient to induce diastolic dysfunction in the absence of hypertension and LV hypertrophy.     

Blood pressure levels of the Suruí and Zoró Indians of the Brazilian Amazon: group- and sex-specific effects resulting from body composition, health status, and age

Two related Tupí-Mondê-speaking tribes of the Aripuan? Indian Park of western Brazil are compared in terms of their recent contact with Western culture, subsistence patterns, general health, and blood pressure levels. Age, weight, height, sex, and tribal affiliation for Suruí and Zoró adults over age 18 are included in an analysis of covariance to test regression models of both diastolic and systolic blood pressure. Because of significant interaction effects between sex and other covariates, sex-specific models were developed. The relationship between body mass and blood pressure level in males conforms with Western data, but the direction and magnitude of effects for the age and body mass covariates in both sexes conflict with data from other modernizing societies. With age, weight/height ratio, and sex differences controlled for, Suruí males show a lower mean systolic blood pressure (SBP) level and diastolic blood pressure (DBP) level than Zoró males. Intertribal differences were smaller among females: Suruí females SBP and DBP differences were similar but did not reach significance. Other sex-specific differences include a greater inverse relationship between age and SBP level among the 104 male subjects than among the 98 female subjects (with similar trends in DBP) and a small but significant effect of the weight/height ratio on both SBP and DBP in males but not in females. Health status data for these groups suggest that hypothesized increases in mean blood pressure levels following the Suruí's acceptance of a Western diet and social stratification may be modified by their health status, particularly prevalent infectious disease.     

Iron deficiency caused by 7 weeks of intensive physical exercise

The present study was designed to evaluate the effect of an intensive physical training program involving both isometric and isotonic activities on the body iron status of 8 females and 11 males (age 20 +/- 1 year). The training was carried out over a 7 week period and included 8 h of varying physical activities each day. Venous blood samples were obtained from the subjects prior to the beginning of the training, on day 2 and in weeks 2, 4, 6 and 7 of the program. Blood samples were analyzed for iron, ferritin and hemoglobin (Hb) concentrations, total iron binding capacity (TIBC) and red blood cell count (RBC). Iron levels of males and females decreased 65% after 2 weeks of training (p less than 0.001). At the end of the training program 5 males and 6 females had lower than normal iron values (less than 13.4 mumol.l-1). TIBC increased 25% in women and 18% in men following 2 and 4 weeks of training (p less than 0.001) and remained at this elevated level throughout the training period. Ferritin levels decreased 50% in both sexes after 4 weeks of exercise (p less than 0.05) and remained at this level until the end of the training. Hb and RBC decreased 8-10% in both sexes during the training period. In two of the women anemia occurred after 4 weeks of training. The development of latent iron deficiency in a substantial number of participants after a relatively short period of training is uncommon and may reflect the high intensity of exercise required in this program.(ABSTRACT TRUNCATED AT 250 WORDS)     

Arousal reduction with biofeedback-supported respiratory meditation

This study investigated the effectiveness of a relaxation procedure that combines a concentration aid, in the form of biofeedback, with elements of approved relaxation procedures. Ten subjects completed two sessions, one with and one without feedback. Half of the subjects started with the feedback session and then completed the session without feedback; the other half had the reverse order. In the experimental procedure, subjects had to concentrate on their exhalation, being supported by respiratory feedback. In the background they heard slow movements of baroque music and relaxation-suggesting sentences. The control procedure contained only background music and relaxation-suggesting sentences. Both procedures elicited a trophotropic response: Finger temperature increased while skin conductance level, number of skin conductance responses, and muscle tension decreased. However, with respiratory feedback and meditation, there was an additional, specific effect, a decrease in respiration and heart rate, to an extent not found in the control procedure. It is suggested that exhalation feedback helps to concentrate on the exhalation process and by this means slows respiration rate, and as a consequence, also heart rate. Therefore, respiratory feedback could be a useful tool for inducing relaxation and slowing of heart rate.The author would like to thank Carlo Thomas for his assistance in the data analysis of the experiment described in the article.     

The relationship between 24-hour ambulatory blood pressures and laboratory measures of cardiovascular reactivity

The relationship between 24-hour ambulatory blood pressures (ABP) and blood pressures (BP) obtained during laboratory stressors was examined. Thirty normotensives (equal males and females) underwent ABP monitoring on three occasions separated by a week. They also underwent a laboratory assessment which included standard stressors (i.e., mental arithmetic, cold pressor, orthostatic response, treadmill exercise). Correlational analyses found laboratory pressures to be significantly correlated with ambulatory pressures, with laboratory baseline BPs showing higher correlations to the ambulatory BPs than the BPs obtained during laboratory stressors. In addition, gender effects were examined. In the correlational analyses between ABPs and laboratory BPs, males and females did not differ significantly in the strength of the correlations. In terms of absolute values, males were found to have significantly higher SBP during ambulatory monitoring, random-zero recordings, calibration readings, and during baselines of the laboratory assessment. There were no gender effects for these measures with respect to diastolic blood pressure or heart rate. There were also no gender effects on reactivity to laboratory stressors as measured by change scores. Exploratory analyses found no significant effect of history of familial hypertension on either the ABPs or the laboratory pressures.     

Psychophysiological investigations on transcendental meditation

Two experiments were conducted to evaluate the psychophysiological changes reported to occur during the practice of transcendental meditation. In Experiment I, 47 volunteers solicited from the community were randomly assigned to transcendental meditation (TM), Benson's relaxation response (BRR), or no treatment (NT) instruction. Respiration rate, heart rate, electromyogram, electroencephalogram, and skin conductance level were recorded during the practice of each technique, approximately 1 week after terminating instruction. The results indicate that while BRR, TM, and NT exhibited different physiological patterns, none of the techniques showed a clear superiority in reducing tonic physiological arousal. In Experiment II, 30 volunteers with previous experience were assigned to one of three groups based on their meditating experience (range 16–96 months). The same physiological signals as in Experiment I were also recorded in this experiment during TM practice. The results suggest that individuals with 1.5 years of meditation experience exhibited physiological arousal levels similar to those seen in persons with over 5 years' experience.This article is based on the author's dissertation submitted to the University of Georgia in partial fulfillment of requirement for the Ph.D. degree. The author would like to thank Dr. L. J. Peacock for his guidance and to acknowledge Student International Meditation Society for their assistance.     

The effect of explicit expectations on initial meditation experiences

Although meditation has been employed successfully as a treatment for various stress-related disorders, there is still little evidence clarifying just which aspects of meditation training are responsible for these therapeutic effects. This experiment sought to test the hypothesis that creating two opposite expectations about an initial meditation experience would result in differing physiological and phenomenological responses, even though the same technique was practiced by all subjects. The results of the experiment failed to support this hypothesis.     

Blood pressure levels of Rellis (India) with special reference to variations with age

The paper presents a survey of arterial blood pressures measured in 193 adult males and females of Relli community, selected at random from Visakhapatnam City, Andhra Pradesh. Age shows more influence on the rise of systolic than diastolic blood pressure. Females show a higher rate of rise in both pressures with advancing age. The incidence of hypertension is also found to be higher in females than in males.     

Alterations in blood pressure due to chronic exposure to natural sour gas leakage containing sulfur compounds

In order to show the alteration of blood pressure in subjects chronically exposed to natural gas containing sulfur compounds, the present study was done. The blood pressure of 94 (43 males, 51 females) of healthy individuals living in the polluted area of Masjid-i-Sulaiman (Khozestan province, southwest of Iran) was measured. The non-parametric Sign test was applied in order to detect differences between the study subjects and the normal mean values according to the sex and age of subjects. Statistical analysis showed that the systolic blood pressure significantly decreased (Z=-2.74; P=0.0031) while the diastolic blood pressure (Z=+2.11; P=0.0174) and heart rate (Z=+3.62; P<0.001) significantly increased in individuals living in the contaminated areas compared with those of normal mean values. The systolic and diastolic blood pressure decreased and increased, respectively, in individuals chronically exposed to natural sour gas containing sulfur compounds.