The effects of leg crossing and applied tension on blood donor return.

BACKGROUND AND OBJECTIVES: Repeated isometric muscle tension (applied tension) during blood donation reduces vasovagal symptoms in many donors. Experiencing vasovagal symptoms has been found to reduce blood donor return. However, does practicing applied tension improve blood donor return? Follow-up results from a randomized controlled trial are presented. METHODS: Data were collected in mobile clinics held in several colleges and universities. During the baseline donation, participants either (1) practiced 'standard' applied tension consisting of repeated 5 s cycles of whole-body isometric muscle tension in the donation chair (N = 133), (2) practiced tension with legs crossed (N = 131), or (3) gave blood as usual (N = 140). Subsequent blood donations in the following 2 years were determined. RESULTS: Applied tension had no effect on immediate (at the end of the baseline blood donation) rating of intention to give blood or the dichotomous measure of whether or not the participant gave blood again in the following 2 years. However, men asked to practice applied tension with legs crossed gave approximately one unit more during the follow-up period compared with men in the control group (F1,106  = 5·32, P = 0·023). This was associated significantly with adherence - men assigned to the applied tension with legs crossed condition who did not practice as instructed were no more likely to return than controls. CONCLUSION: The results provide modest support for the idea that applied tension may increase subsequent blood donation though the results were limited to men who practiced the technique as instructed.

Applied tension may help retain donors who are ambivalent about needles.

BACKGROUND: Vasovagal symptoms can discourage people who might otherwise give blood on many occasions. However, the effects of symptoms on donor retention as well as the effects of treatments to reduce vasovagal symptoms on donor retention are probably moderated by a person's confidence that they can tolerate the procedure. METHODS: Data from a study on the effects of the muscle tensing technique applied tension (AT) on donor retention were examined to determine if (1) the degree of donor ambivalence about needles influenced the impact of vasovagal symptoms on subsequent return and (2) ambivalence about needles moderated the effect of learning AT on donor return. One-year follow-up data on 614 people who had previously given blood and were randomly assigned to either a no treatment, donation-as-usual condition or one of two conditions involving AT were obtained. Self-reported degree of needle ambivalence and vasovagal symptoms were assessed during the initial blood donation. RESULTS: Among participants in the no treatment group, increases in vasovagal symptoms were associated with decreases in donor return but only among people who expressed some fear of blood draws. Similarly, among people who expressed no fear of needles, learning AT had no effect on post-donation estimate of the likelihood they would give blood again or return rate. However, among people with some fear of blood draws learning AT led to both a higher estimate that they would give blood again as well as actual return rate. CONCLUSIONS: The experience of vasovagal symptoms may not deter people who are generally confident in their ability to tolerate blood donation. However, among people who are ambivalent about needles, symptoms may 'confirm' pre-existing doubts about their suitability for blood donation and lead to drop-out. Targeted interventions that give the uncertain volunteer a sense of confidence that they might be able to realize their goal and become a regular blood donor may be useful.

Expectancies mediate the relationship between perceived injustice and return to work following whiplash injury: A 1-year prospective study.

BACKGROUND: Emerging evidence suggests that perceived injustice is a risk factor for work disability in individuals with whiplash injury. At present, however, little is known about the processes by which perceived injustice impacts on return to work. The purpose of this study was to examine whether expectancies mediated the relationship between perceived injustice and return to work in patients with whiplash injury. METHOD: One hundred and fifty-two individuals (81 men, 71 women) with a primary diagnosis of whiplash injury completed self-report measures of pain intensity, perceived injustice and return-to-work expectancies following admission to a rehabilitation programme. Work status was assessed 1 year after discharge. RESULTS: Consistent with previous research, high scores on a measure of perceived injustice were associated with prolonged work disability. Results indicated that high perceptions of injustice were associated with low return-to-work expectancies. Causal mediation analyses revealed that expectancies fully mediated the relationship between perceived injustice and return to work. CONCLUSION: The findings suggest that intervention techniques designed to target expectancies could improve return-to-work outcomes in patients with whiplash injury. Discussion addresses the processes by which expectancies might impact on return-to-work outcomes and the manner in which negative return-to-work expectancies might be modified through intervention. SIGNIFICANCE: The study confirms that expectancies are the mechanism through which perceived injustice impacts return to work following whiplash injury. The findings suggest that interventions designed to specifically target return-to-work expectancies might improve rehabilitation outcomes in patients with whiplash injury.

The role of ischaemia and pain in the blood pressure response to exercise stress testing in patients with coronary heart disease.

Silent myocardial ischaemia is a common phenomenon in patients with coronary heart disease. However, very little is known about the underlying mechanisms of silent ischaemia. One potential pathway that may contribute to this absence of pain is increased blood pressure. The main aim of the current study was to assess the associations among blood pressure, pain and ischaemia in patients undergoing a standard exercise stress test. We hypothesized that patients who experienced chest pain during exercise would have lower baseline and peak blood pressures compared to those who did not experience chest pain. A total of 1,355 patients (418 women) who underwent a single-photon emission computed tomography treadmill exercise stress test and had not experienced a cardiac event in the past 2 weeks participated in the current study. Myocardial perfusion defects were assessed at rest and during the stress challenge. Systolic blood pressure (SBP), diastolic blood pressure, heart rate (HR) and rate pressure product (RPP) were assessed during rest and at peak exercise. There were no main effects of either pain or ischaemia on the baseline cardiovascular variables. Peak exercise data revealed main effects of pain on SBP, RPP and HR, and main effects of ischaemia on SBP and RPP, controlling for age, sex, baseline level, medication status and cardiac history. These findings suggest that acute rather than chronic increases in blood pressure may be one mechanism to explain the phenomena of silent myocardial ischaemia in cardiac patients, and may potentially provide a target for future treatment strategies.

Forearm blood flow responses of offspring of hypertensives to an extended stress task.

The forearm blood flow and other cardiovascular responses of 10 healthy young men with a parental history of hypertension to an extended laboratory stressor were compared with the responses of 10 age-matched men with normotensive parents. To eliminate the effects of the anticipation of stress on baseline measures, all subjects participated in a separate 1-hour counterbalanced baseline session in which no stress was presented. There were no significant differences between the two groups in resting blood pressure, heart rate, blood volume pulse, forearm blood flow and vascular resistance, and self-report anxiety, although offspring of hypertensive parents exhibited marginally greater (p = 0.08) forearm blood flow at rest. During the stress session, subjects played video games for 1 hour and avoided mild electric shocks depending on performance. Offspring of hypertensive parents exhibited significantly greater heart rate (+19 +/- 6 vs. +3 +/- 2%), forearm blood flow (+52 +/- 14 vs. +9 +/- 4%), and self-report anxiety (+25 +/- 6 vs. +9 +/- 3%) responses to the task. There were no significant group differences in blood pressure response to the task. Significant positive correlations between forearm blood flow and heart rate responses to the task were observed. These findings extend earlier results that suggested healthy young offspring of hypertensive and normotensive parents may exhibit different patterns of hemodynamic response to stress in the absence of differences in resting blood pressure or blood pressure responsiveness to stress.

A controlled evaluation of paraspinal EMG biofeedback in the treatment of chronic low back pain.

Sixty-six chronic low back pain sufferers were randomly divided into three groups. Following individual assessments consisting of psychological questionnaires, pain monitoring, and measurement of paraspinal electromyogram (EMG), one group received paraspinal EMG biofeedback and another a placebo treatment. The third group received no intervention. Two further assessments were carried out on all groups immediately after treatment and at a 3-month follow-up. All groups showed significant reduction in pain, anxiety, depression, and paraspinal EMG following treatment and at follow-up, but there were no differences between groups. A regression analysis failed to identify subjects' characteristics that predicted positive outcome in the biofeedback group. However, high scores on the Evaluative scale of the McGill Pain Questionnaire and high hypnotizability were significant predictors of positive outcome for the placebo group. It is concluded that paraspinal EMG biofeedback is not a specific treatment for chronic low back pain in a nonhospitalized population.

Spouse and parent-offspring similarities in cardiovascular response to mental arithmetic and isometric hand-grip.

Thirty spouse pairs were recruited for a stress protocol consisting of alternating stress and relaxation periods. Repeated measurements of blood pressure, heart rate, and blood volume pulse were obtained. Spouse pairs were parents of young adult sibling pairs who had previously participated in a slightly different version of the protocol. Although spouses exhibited some behavioral similarities, there were no significant similarities in cardiovascular response to stress. However, despite the fact that parents and their offspring were tested on different occasions using somewhat different procedures, some similarities in cardiovascular reactivity were observed. Significant parent-offspring similarities in heart-rate response to mental arithmetic and diastolic blood pressure response to isometric hand-grip were observed, as well as several behavioral similarities. Assortative mating and the nature of one's current home environment seem to be less important in the familial aggregation of cardiovascular reactivity to stress than early environmental and/or genetic factors.

Risk for hypertension and pain sensitivity in adolescent boys.

Reduced pain perception has been observed in many studies of spontaneously hypertensive rats and human hypertensive patients. To determine whether a reduced sensitivity to pain could be observed in a group of clearly normotensive individuals who may be at risk for hypertension, a mild to moderate pain stimulus was administered to 177 14-year-old boys. Boys with a normatively elevated resting systolic blood pressure tolerated mechanical finger pressure significantly longer than boys with lower blood pressure. As well, boys with both normatively elevated resting systolic blood pressure and a parental history of hypertension reported significantly less pain during finger pressure than lower risk participants. These findings could not be explained by personality factors and suggest that hypertension-related hypoalgesia is associated with processes involved in the development of the disorder.

Age differences in the consistency of cardiovascular response patterns in healthy women.

To determine if response consistency is higher in older women, twenty young adult (mean = 20 years) and twenty-two elderly (mean = 82 years) women participated in a 20-min stress protocol including serial subtraction, anxiety and anger imagery tasks. All subjects were healthy and free of diagnosed cardiovascular disease. Heart rate (HR), systolic blood pressure (SBP), and diastolic blood pressure (DBP) responses to the tasks were assessed. To allow comparisons of the effects of stress on different cardiovascular parameters, all baseline-stress change scores were converted to z-scores. Forty-two 3(parameter)X3(stressor) matrices of z-scores, one for each subject, were created. Intraclass correlations computed using these matrices revealed greater consistency of response hierarchies (e.g., DBP greater than SBP greater than HR) among elderly subjects. Possible mechanisms for this effect are discussed.

Cardiopulmonary baroreflex stimulation and blood pressure-related hypoalgesia.

Results from both experimental animals and humans suggest that baroreflex stimulation may be involved in blood pressure-related hypoalgesia. However, most of this research, especially in the area of human experimentation, has focused on sinoaortic baroreceptors. Cardiopulmonary baroreflex stimulation may also be an important moderator of pain. Sixty-six healthy male undergraduates varying in risk for hypertension participated in an experimental protocol in which painful mechanical finger pressure was presented three times in a counterbalanced fashion. One pain stimulus was preceded by 6 min of supine rest, another by a period of rest interspersed with periodic Valsalva manoeuvres, and another by a period in which cardiopulmonary baroreceptors were stimulated by passive leg elevation. Significantly lower pain was reported by men with relatively elevated systolic blood pressure following leg elevation but not the other conditions. Cardiopulmonary baroreflex stimulation was documented by increased forearm blood flow and other data obtained via impedance cardiography. These results suggest that blood pressure related hypoalgesia may be at least partially related to cardiopulmonary baroreflex stimulation.

Baroreflex sensitivity at rest and during stress in individuals with a history of vasovagal syncope.

The baroreflex sensitivity of healthy young adult males who reported some history of vasovagal syncope during emotionally stressful situations (e.g. blood donation) was compared to a control group of individuals who reported no such history. The baroreflex, which induces compensatory bradycardia and vasodilation in response to acute elevations of blood pressure, was examined as a possible mechanism underlying predisposition to vasovagal reactions. Changes in heart rate and vasoconstriction in response to baroreflex stimulation (negative external cervical pressure) at rest and during administration of a mental arithmetic task and a constrictive pain stimulus were assessed. Individuals with a history of vasovagal reactions displayed greater baroreflex sensitivity during the pain stimulus and at rest, but not during mental arithmetic. These findings suggest one mechanism of risk for syncope reactions, particularly in situations involving the experience of pain.

Cardiovascular reactions to blood donation in offspring of hypertensives and normotensives.

Blood pressure and heart rate reactions of 182 confirmed offspring of normotensive (110 female, 72 male) and 112 offspring of hypertensive (66 female, 46 male) individuals to the stressor of blood donation were examined. Subjects were tested at two sites, one in the United States and one in Canada. Although influenced by site, young normotensive offspring of hypertensives generally exhibited significantly greater blood pressure levels in anticipation of donating blood than offspring of normotensives. The higher reactivity of offspring of hypertensives observed in stressful laboratory settings may generalize to more ecologically valid settings, even those which, like blood donation, require passive coping efforts.

Interpersonal behavior and resting blood pressure in college women: a daily monitoring study.

UNLABELLED: Psychological factors have long been implicated in the development of hypertension. Most studies exploring this relationship employed questionnaires administered on only one occasion. OBJECTIVE: to evaluate the relation between blood pressure and social behavior in the natural environment over an extended period of time. METHOD: 40 healthy young adult women at varying risk for hypertension were asked to record their behavior and affect following social interactions, three times a day for 32 days. Behaviors were representative of the interpersonal circumplex: dominance, submissiveness, agreeableness, and quarrelsomeness. RESULTS: Casual blood pressure was significantly correlated with submissive behavior (r=.45, P<.05) and inversely correlated with agreeable behavior (r=-.35, P<.05). ANOVAs confirmed these findings and further revealed that offspring of hypertensives with relatively elevated blood pressure were most quarrelsome. CONCLUSION: These results concur with the literature on the relationship between hostility and blood pressure but also suggest the importance of submissiveness in college women.

The effects of sodium loading on blood pressure and pain responses to the cold pressor test.

Two cold pressor tests were administered to 18 healthy normotensive males on two occasions, after 2 weeks of dietary sodium loading and after 2 weeks of maintaining their normal diet. While the addition of an extra 10 g/day of sodium to the diet had no overall effect on resting cardiovascular activity, it produced significantly greater diastolic blood pressure and smaller heart rate responses to the pain stimuli. As well, consistent with the large animal literature indicating a relationship between high blood pressure and diminished pain sensitivity, pain ratings were found to be significantly lower during the sodium loaded testing session. The ratings were corroborated by evidence of lower skin conductance reactivity to the second cold pressor test in the sodium loaded condition. Information concerning an elevation of risk for hypertension, perhaps provided by baroreceptors, may lead to compensatory reactions with hypoalgesia as one effect.

Prevalence, disclosure and interpretations of sexual activities in a sample of Canadian college-aged blood donors.

This study assessed the prevalence, level of disclosure, and interpretations of sexual activities in a sample of 123 college-aged blood donors in Montreal, Quebec. Within six months of their donation, participants completed an anonymous questionnaire designed to assess sexual definitions, levels of disclosure to sexual partners, as well as prevalence of various blood safety behavioural risks. Responses indicated that (1) there was a lack of consensus regarding what constitutes 'sex', (2) levels of sexual disclosure varied widely, and (3) participants engaged in numerous blood safety behavioural risk activities. These results are discussed with respect to their implications for how people think about sex, particularly in the blood donation context. Suggestions to improve specific blood donor screening questions are also presented.

Psychophysiological effects of interviews about emotional events on offspring of hypertensives and normotensives.

Normotensive individuals with a parental history of hypertension have been found to exhibit greater cardiovascular reactivity to a variety of laboratory stressors than offspring of normotensives. To examine the possible generalization of these differences to real-life stressors, subjects were administered four brief interviews about different emotional events in their lives. Regardless of emotional content, offspring of hypertensives displayed greater systolic blood pressure responses to the non-verbal recollection and verbal description of personal emotional events, but not to the imagination of standardized emotional scenes or reading a non-emotional advertisement. This suggests that group differences in reactivity may generalize to real-world situations. Evidence of significantly greater vasoconstriction during interviews about sad topics was also observed, contributing to the literature on the physiological differentiation of emotional states.

Risk for hypertension and diminished pain sensitivity in women: autonomic and daily correlates.

Research suggests an association between risk for hypertension and decreased pain sensitivity. However, few studies have utilized non-behavioral indices of pain to corroborate subjective reports or sought to generalize these findings to women. Furthermore, it has not been established whether results obtained using well-controlled laboratory pain stimuli extend to naturalistic pain. In Study 1, 80 young adult women with (N = 40) and without (N = 40) a parental history of hypertension and with either normatively low or high resting systolic blood pressure (SBP) were exposed to two experimental pain stimuli, finger pressure and the cold pressor test. In addition to behavioral pain measures, respiratory sinus arrhythmia (RSA) reactions to pain were also assessed. Women with a parental history of hypertension and/or normatively high resting SBP experienced significantly less pain, as assessed by both behavioral and RSA measures. In Study 2, 37 of the participants from Study 1 monitored their behaviors, affect, and physical symptoms, three times a day for 32 days. Laboratory pain sensitivity was significantly correlated with daily reports of pain but not gastrointestinal symptoms. The present results confirm an association between risk for hypertension and hypoalgesia in women and suggest generalizability of this relationship to everyday life.

Familial influences on heart rate, blood pressure, and self-report anxiety responses to stress: results from 100 twin pairs.

Two hundred healthy adolescent to middle-aged individuals (12-44 years, M = 20 years) were tested in a standardized stress protocol. These individuals comprised 20 monozygotic female, 20 monozygotic male, 20 same-sex dizygotic female, 20 same-sex dizygotic male, and 20 opposite-sex dizygotic twin pairs. Familial influences on heart rate, blood pressure, and self-report anxiety responses to four different kinds of stressors (Visual-Verbal Test for Conceptual Thought, mental arithmetic, isometric handgrip, cold pressor) were assessed using biometrical genetic model fitting. Evidence of significant genetic effects on resting heart rate and blood pressure was obtained, providing heritability estimates of .65, .63, and .58 for resting heart rate and systolic and diastolic blood pressure, respectively. Cardiovascular reactivity to the Visual-Verbal Test, mental arithmetic, and the cold pressor test appeared to be primarily influenced by genetic and idiosyncratic (nonfamilial) environmental factors, whereas reactivity to handgrip was more related to effects of the family environment. The results of multivariate model fitting suggested that the genetic effects on reactivity were relatively independent of those affecting resting heart rate and blood pressure and that there was significant overlap of genetic influences on heart rate and blood pressure responses to the two active coping tasks.

Caffeine effects on several indices of cardiovascular activity at rest and during stress.

The effects of caffeine on cardiovascular responses to a mental arithmetic task were assessed using a between-subjects, double-blind design. Thirty-six male undergraduates were randomly assigned to either a placebo group or a group which received 250mg of caffeine. Repeated measurements of systolic and diastolic blood pressure (SBP, DBP), heart rate (HR), digital blood volume pulse (DBVP), and finger pulse transit time (FPTT) were obtained during a predrug baseline, a postdrug resting period, and a mental arithmetic task. Significant Period (i.e., stress) effects were observed on all measures, except DBVP which revealed a marginally significant Period effect. Significant main effects of Drug were observed on DBP and DBVP. There were no significant Drug x Period interactions. These results indicate that the increases in DBP and the decreases in DBVP produced by caffeine were additive with effects produced by stress.