The cold pressor test: vascular and myocardial response patterns and their stability

Validity of mental and physical stress models

Different stress models are employed to enhance our understanding of the underlying mechanisms and explore potential interventions. However, the utility of these models remains a critical concern, as their validities may be limited by the complexity of stress processes. Literature review revealed that both mental and physical stress models possess reasonable construct and criterion validities, respectively reflected in psychometrically assessed stress ratings and in activation of the sympathoadrenal system and the hypothalamic-pituitary-adrenal axis. The findings are less robust, though, in the pharmacological perturbations' domain, including such agents as adenosine or dobutamine. Likewise, stress models' convergent- and discriminant validity vary depending on the stressors' nature. Stress models share similarities, but also have important differences regarding their validities. Specific traits defined by the nature of the stressor stimulus should be taken into consideration when selecting stress models. Doing so can personalize prevention and treatment of stress-related antecedents, its acute processing, and chronic sequelae. Further work is warranted to refine stress models' validity and customize them so they commensurate diverse populations and circumstances.

Interindividual variability in cold-pressor pain sensitivity is not explained by peripheral vascular responding and generalizes to a C-nociceptor-specific pain phenotype

ABSTRACT

Pain sensitivity of healthy subjects in the cold-pressor (CP) test was proposed to be dichotomously distributed and to represent a pain sensitivity trait. Still, it has not been systematically explored which factors influence this pain sensitivity readout. The aim of this study was to distinguish potential contributions of local tissue-related factors such as perfusion and thermoregulation or gain settings in nociceptive systems. Cold-pressor-sensitive and CP-insensitive students screened from a medical student laboratory course were recruited for a CP retest with additional cardiovascular and bilateral local vascular monitoring. In addition, comprehensive quantitative sensory testing according to Deutscher Forschungsverbund Neuropathischer Schmerz standards and a sustained pinch test were performed. Cold pressor was reproducible across sessions (Cohen kappa 0.61 ± 0.14, P < 0.005). At 30 seconds in ice water, CP-sensitive subjects exhibited not only more pain (78.6 ± 26.3 vs 29.5 ± 17.5, P < 0.0001) but also significantly stronger increases in mean arterial blood pressure (12.6 ± 9.3 vs 5.6 ± 8.1 mm Hg, P < 0.05) and heart rate (15.0 ± 8.2 vs 7.1 ± 6.2 bpm, P < 0.005), and lower baroreflex sensitivity, but not local or vasoconstrictor reflex-mediated microcirculatory responses. Cold-pressor-sensitive subjects exhibited significantly lower pain thresholds also for cold, heat, and blunt pressure, and enhanced pain summation, but no significant differences in Aδ-nociceptor-mediated punctate mechanical pain. In conclusion, differences in nociceptive signal processing drove systemic cardiovascular responses. Baroreceptor activation suppressed pain and cardiovascular responses more efficiently in CP-insensitive subjects. Cold-pressor sensitivity generalized to a pain trait of C-fiber-mediated nociceptive channels, which was independent of local thermal and vascular changes in the ice-water-exposed hand. Thus, the C-fiber pain trait reflects gain setting of the nociceptive system.

Auricular Acupressure Effect on Autonomic Responses Evoked by a Cold Pressor Test in Healthy Volunteers: A Pilot Study

Objective

This pilot study was conducted to investigate changes in the pulse rate and blood pressure in healthy volunteers after applying auricular acupressure at the "heart acupoint."

Methods

A total of 120 healthy volunteers with hemodynamic indexes within normal limits were randomly allocated into 4 groups to receive auricular acupressure treatment either at the heart acupoint of the left or the right, or in both ears, and one control group without applying auricular acupressure.

Results

Before the application of auricular acupressure, there were no statistical differences in pulse rate and blood pressure increments among the four groups during the first cold pressor test. In groups in which auricular pressure was applied, the pulse rate was significantly reduced after the application of auricular acupressure in three groups; however, no statistically significant difference was detected among the groups. Changes in blood pressure were not statistically significant in or among the different groups after applying auricular acupressure. The average recorded pulse rate values during the second cold pressor test (after auricular acupressure) were significantly lower compared to the corresponding values taken during the first cold pressor test (before auricular acupressure) (p < 0.05); however, pulse rate increments during the two cold pressor tests (with and without auricular acupressure) were similar (p > 0.05).

Conclusions

These findings suggest that auricular acupressure could be used as an adjunctive nonpharmacological method for reducing the pulse rate.

Effect of oral hormonal contraceptive pill use on the hemodynamic response to the cold pressor test

Acute increases in sympathetic nervous system activity (SNA) often elicit peripheral vasoconstriction and increases in blood pressure (BP). Given sympathetic support of BP is modulated by ovarian sex hormones (e.g., estradiol), we sought to examine the effect of menstrual cycle and oral hormonal contraceptive pill (OC) phase on the hemodynamic response to acute increases in SNA. We hypothesized sympathoexcitation via cold pressor test (CPT) would elicit greater peripheral vasoconstriction and increases BP in females with natural menstrual cycles (NC) compared with females taking OC. We further hypothesized that SNA-mediated vasoconstriction would be attenuated during the high estradiol (HE) phase versus the low estradiol (LE) phase of the menstrual/pill cycle. Female NC (n = 11, 25 ± 1 yr) and OC (n = 10, 24 ± 1 yr) participants were studied during the LE (early follicular, placebo pill) and HE (late follicular, active pill) phase of the menstrual/pill cycle. BP (finger photoplethysmography), heart rate (HR, ECG), and forearm blood flow (FBF, venous occlusion plethysmography) were measured during a 5-min baseline and a 2-min CPT. CPT elicited an increase in BP in both groups (time, P < 0.01). During CPT, OC participants exhibited greater and sustained increases in HR compared with NC participants (group × time, P < 0.01). Higher HRs were met with increases in FBF in OC participants during the CPT, which was not observed in NC participants (group × time, P < 0.01). OC participants exhibit greater increases in HR, and paradoxical vasodilation during acute sympathetic activation compared with NC participants. Group differences are unaffected by menstrual/pill phase.NEW & NOTEWORTHY Acute increases in sympathetic nervous system activity often elicit peripheral vasoconstriction and increases in blood pressure (BP). Given sympathetic support of BP is modulated by ovarian sex hormones (e.g., estradiol), we sought to examine the effect of menstrual cycle and oral hormonal contraceptive pill (OC) phase on the hemodynamic response to acute increases in sympathetic nervous system activity via the cold pressor test. We show OC participants exhibit paradoxical vasodilation during acute sympathetic activation compared with participants with natural menstrual cycles; notably, group differences were unaffected by menstrual/pill phase.

Functional assessment of bidirectional cortical and peripheral neural control on heartbeat dynamics: a brain-heart study on thermal stress

The study of functional brain-heart interplay (BHI) from non-invasive recordings has gained much interest in recent years. Previous endeavors aimed at understanding how the two dynamical systems exchange information, providing novel holistic biomarkers and important insights on essential cognitive aspects and neural system functioning. However, the interplay between cardiac sympathovagal and cortical oscillations still has much room for further investigation. In this study, we introduce a new computational framework for a functional BHI assessment, namely the Sympatho-Vagal Synthetic Data Generation Model, combining cortical (electroencephalography, EEG) and peripheral (cardiac sympathovagal) neural dynamics. The causal, bidirectional neural control on heartbeat dynamics was quantified on data gathered from 26 human volunteers undergoing a cold-pressor test. Results show that thermal stress induces heart-to-brain functional interplay sustained by EEG oscillations in the delta and gamma bands, primarily originating from sympathetic activity, whereas brain-to-heart interplay originates over central brain regions through sympathovagal control. The proposed methodology provides a viable computational tool for the functional assessment of the causal interplay between cortical and cardiac neural control.

Gaming Instead of Training? Exergaming Induces High-Intensity Exercise Stimulus and Reduces Cardiovascular Reactivity to Cold Pressor Test

Introduction

The present study assessed if an exercise session in an innovative exergame can modulate hemodynamic reactivity to a cold pressor test (CPT) to a similar extent as a typical moderate endurance training (ET). Furthermore, cardiorespiratory, and affective responses of an exergame session and an ET were compared.

Methods

Twenty-seven healthy participants aged 25 ± 4 years (48% female; BMI 23.0 ± 2.1 kg/m2) participated in this cross-sectional study. All participants completed both an ET on a treadmill and training in the ExerCube (ECT). HR and oxygen consumption were recorded during both training sessions. Before and after both exercise sessions, the hemodynamic reactivity to a CPT was determined.

Results

During ECT, HR, oxygen consumption, energy expenditure, and the metabolic equivalent of the task were significantly higher than those obtained during ET (p &lt; 0.001). With regard to the CPT, the participants showed significantly lower responses in peripheral systolic (p = 0.004) and diastolic blood pressure (p = 0.009) as well as central systolic (p = 0.002) and diastolic BP (P = 0.01) after ECT compared to ET. The same was true for pulse wave velocity (p = 0.039).

Conclusion

The ECT induced a significantly higher exercise stimulus compared to the ET. At the same time, it attenuated hemodynamic stress reactivity. The ECT presents a relevant training stimulus that modulates cardiovascular reactivity to stress, which has been proven as a predictor for the development of hypertension.

Trial Registration

ISRCTN registry, ISRCTN43067716, 14 April 2020, Trial number: 38154.

Validation and Cross-Cultural Adaptation of the Spanish Version of the Pain Sensitivity Questionnaire (PSQ-S)

Experimental pain testing requires specific equipment and may be uncomfortable for patients. The Pain Sensitivity Questionnaire (PSQ) was developed to assess pain sensitivity, based on the pain intensity ratings (range: 0–10) of painful situations that occur in daily life. The main objective of this study was to carry out a cross-cultural adaptation and validation of the Spanish version of the PSQ (PSQ-S). A total of 354 subjects (296 healthy and 58 chronic pain patients) filled in the PSQ-S. A subgroup of 116 subjects performed experimental pain testing, including two modalities (cold and pressure), with different measures: pain intensity rating, pressure pain threshold, and tolerance. The validation results showed two factors: PSQ-S-moderate and PSQ-S-minor and, for the total scale and the two factors, an excellent internal consistency (Cronbach’s alpha coefficient > 0.9) and a substantial reliability (Intraclass Correlation Coefficient > 0.8). We obtained strong correlations with all the experimental pain rating parameters, catastrophizing, and depression variables, as well as moderate correlations with anxiety, central sensibilization, and impact on the quality of life. Chronic pain patients received elevated PSQ-S scores compared to healthy controls, and three cut-off values (PSQ-S-total = 7.00, PSQ-S-moderate = 7.57, and PSQ-S-minor = 6.29) based on ROC curve analyses were shown to be able to discriminate between healthy adults and adults with chronic pain. Therefore, PSQ-S may be a simple alternative to experimental pain procedures for clinical and experimental pain research.

Effects of Music and Relaxation Suggestions on Experimental Pain

Pain is a significant public healthcare challenge. There is growing support for the use of music and suggestive techniques as adjuvant pain treatments. The purpose of this study was to (1) examine the effects of music listening combined with relaxation suggestions compared to music alone and silence on experimental pain, and (2) to explore the potential mechanisms of music-induced analgesia. Sixty-six healthy females were randomized to receive either (1) music plus relaxation suggestions, (2) music alone, or (3) silence. Pain and psychological constructs were assessed following two cold-pressor trials. Between-group comparisons indicated that music and suggestions for relaxation are not superior to music alone for pain. More research is needed to explore the effect of analgesic suggestions in combination with music to further investigate music's potential in clinical pain management.

Establishing the validity of a novel passive stress task

Laboratory tasks used to elicit a cardiovascular stress response in the laboratory can involve either active or passive coping. However, in previous work, passive stress tasks often incorporate a distinct physical stress element, such as the handgrip or cold pressor task, meaning observed changes in cardiovascular parameters may be the result of the physical element of the stressor rather than truly reflecting psychological stress. The present study aimed to establish the validity of a psychological passive stressor; one more analogous to active tasks than those previously employed in laboratory studies. Twenty-six young, healthy adults completed a speech task in the laboratory following a resting baseline period. Twelve months later, they were invited back to the laboratory and watched the video recording of their speech. Analyses confirmed that while both tasks elicited significant SBP and DBP change (all ps < .001), only the active task was associated with HR and CO reactivity (both ps < .001), while only the passive task was associated with TPR reactivity (p = .028). Furthermore, the passive stressor was associated with a mixed hemodynamic profile, whereas the active stressor was associated with a clear myocardial profile. This study confirms that watching a video recording of oneself complete a speech task is associated with a more vascular response profile, a response associated with passive coping contexts.

The Potential of Wearable Limb Ballistocardiogram in Blood Pressure Monitoring via Pulse Transit Time

The goal of this study was to investigate the potential of wearable limb ballistocardiography (BCG) to enable cuff-less blood pressure (BP) monitoring, by investigating the association between wearable limb BCG-based pulse transit time (PTT) and BP. A wearable BCG-based PTT was calculated using the BCG and photoplethysmogram (PPG) signals acquired by a wristband as proximal and distal timing reference (called the wrist PTT). Its efficacy as surrogate of BP was examined in comparison with PTT calculated using the whole-body BCG acquired by a customized weighing scale (scale PTT) as well as pulse arrival time (PAT) using the experimental data collected from 22 young healthy participants under multiple BP-perturbing interventions. The wrist PTT exhibited close association with both diastolic (group average r = 0.79; mean absolute error (MAE) = 5.1 mmHg) and systolic (group average r = 0.81; MAE = 7.6 mmHg) BP. The efficacy of the wrist PTT was superior to scale PTT and PAT for both diastolic and systolic BP. The association was consistent and robust against diverse BP-perturbing interventions. The wrist PTT showed superior association with BP when calculated with green PPG rather than infrared PPG. In sum, wearable limb BCG has the potential to realize convenient cuff-less BP monitoring via PTT.

Data mining investigation of the association between a limb ballistocardiogram and blood pressure

OBJECTIVE

To investigate the association between a limb ballistocardiogram (BCG) and blood pressure (BP) based on data mining.

APPROACH

During four BP-perturbing interventions, the BCG and reference BP were measured from 23 young, healthy volunteers using a custom-manufactured wristband equipped with a MEMS accelerometer and a commercial continuous BP measurement device. Both timing and amplitude features in the wrist BCG waveform were extracted, and significant features predictive of diastolic (DP) and systolic (SP) BP were selected using stepwise linear regression analysis. The selected features were further compressed using principal component analysis to yield a small set of DP and SP predictors. The association between the predictors thus obtained and BP was investigated by multivariate linear regression analysis.

MAIN RESULTS

The predictors exhibited a meaningful association with BP. When three most significant predictors were used for DP and SP, a correlation coefficient of r  =  0.75  ±  0.03 (DP) and r  =  0.75  ±  0.03 (SP), a root-mean-squared error (RMSE) of 7.4  ±  0.6 mmHg (DP) and 10.3  ±  0.8 mmHg (SP), and a mean absolute error (MAE) of 6.0  ±  0.5 mmHg (DP) and 8.3  ±  0.7 mmHg (SP) were obtained across all interventions (mean  ±  SE). The association was consistent in all the individual interventions (r  ⩾  0.68, RMSE  ⩽  5.7 mmHg, and MAE  ⩽  4.5 mmHg for DP as well as r  ⩾  0.61, RMSE  ⩽  7.9 mmHg, and MAE  ⩽  6.4 mmHg for SP on the average). The minimum number of requisite predictors for robust yet practically realistic BP monitoring appeared to be three. The association between predictors and BP was maintained even under regularized calibration (r  =  0.63  ±  0.05, RMSE  =  9.3  ±  0.8 mmHg, and MAE  =  7.6  ±  0.7 mmHg for DP as well as r  =  0.60  ±  0.05, RMSE  =  14.7  ±  1.4 mmHg, and MAE  =  11.9  ±  1.1 mmHg for SP (mean  ±  SE)). The requisite predictors for DP and SP were distinct from each other.

SIGNIFICANCE

The results of this study may provide a viable basis for ultra-convenient BP monitoring based on a limb BCG alone.

Prediction of autonomic neuropathy in chronic kidney disease (stage 5) Iraqi patients (case control study)

BACKGROUND

The presence of autonomic neuropathy in association with end stage chronic kidney disease have not yet been established. An extending studies need to evaluate the presence of autonomic neuropathy in different stages of chronic kidney disease.

OBJECTIVES

To estimate the prevalence rate of autonomic neuropathy in stage 5 chronic kidney disease.

METHODS

35 patients with end stage CKD were selected (patient group), compared with 100 person had CKD of different stages other than stage 5 CKD (control group). A sequence of questionnaires (6 questions) were applied to both groups, followed by testing for postural hypotension using as a complementary test for ANP with the cold immersion test. Any subject failed to show an increment in BP was labeled as having test positive and hence having ANP.

RESULTS

The distribution of ANP according to the questionnaire was higher in the patient's group than the controls (p<0.0001). Postural hypotension was more in patients versus the control (p 0.026). The Cold immersion test was positive in 23 subject in patients (65.7%) than the control only 11 subject (11%), (p<0.0001).

Acetylcholine versus cold pressor testing for evaluation of coronary endothelial function

Background

Assessment of coronary endothelial function with intracoronary acetylcholine (IC-Ach) provides diagnostic and prognostic data in patients with suspected coronary microvascular dysfunction (CMD), but is often not feasible due in part to the time and expertise needed for pharmacologic mixing. Cold pressor testing (CPT) is a simple and safe stimulus useful for either invasive or non-invasive endothelial function testing and myocardial perfusion imaging but has not been specifically evaluated among symptomatic women with signs of ischemic heart disease (IHD) who have no obstructive coronary artery disease (CAD).

Methods

163 women with signs and symptoms of IHD and no obstructive CAD from the NHLBI- Women’s Ischemia Syndrome Evaluation-Coronary Vascular Dysfunction (WISE-CVD) study underwent coronary reactivity testing with a Doppler flow wire (FloWire^® Volcano, San Diego, CA) in the proximal left anterior descending artery. Coronary artery diameter and coronary blood flow (CBF) assessed by core lab using QCA before and after IC-Ach (18.2 μg/ml infused over 3 minutes) and during CPT.

Results

Mean age was 55 ± 12 years. Rate pressure product (RPP) in response to IC-Ach did not change (baseline to peak, P = 0.26), but increased during CPT (363±1457; P = 0.0028). CBF in response to CPT was poorly correlated to IC-Ach CBF. Change in coronary artery diameter after IC-Ach correlated with change after CPT (r = 0.59, P<0.001). The correlation coefficient was stronger in subjects with coronary dilation to IC-Ach (r = 0.628, P<0.001) versus those without dilation (r = 0.353, P = 0.002), suggesting that other factors may be important to this relationship when endothelium is abnormal.

Conclusions

In women with no obstructive CAD and suspected CMD, coronary diameter changes with IC-Ach and CPT are moderately-well correlated suggesting that CPT testing may be of some use, particularly among patients with normal endothelial function, however, not an alternative to IC-Ach for diagnosis of coronary endothelial dysfunction.

Symptoms of anxiety and depression are related to cardiovascular responses to active, but not passive, coping tasks

Objective:

Anxiety and depression have been linked to blunted blood pressure (BP) and heart rate (HR) reactions to mental stress tests; however, most studies have not included indices of underlying hemodynamics nor multiple stress tasks. This study sought to examine the relationships of anxiety and depression with hemodynamic responses to acute active and passive coping tasks.

Methods:

A total of 104 participants completed the Hospital Anxiety and Depression Scales and mental arithmetic, speech, and cold pressor tasks while BP, HR, total peripheral resistance, and cardiac output (CO) were assessed.

Results:

After adjustment for traditional risk factors and baseline cardiovascular activity, depression scores were negatively associated with systolic BP, HR, and CO responses to the mental arithmetic task, while anxiety scores were inversely related to the systolic BP response to mental arithmetic.

Conclusion:

High anxiety or depression scores appear to be associated with blunted cardiac reactions to mental arithmetic (an active coping task), but not to the cold pressor test or speech tasks. Future research should further examine potential mechanisms and longitudinal pathways relating depression and anxiety to cardiovascular reactivity.

Clinical trial registration number:

TCTR20160208004

Reliable Digit Span is Unaffected by Laboratory-Induced Pain

Reliable Digit Span (RDS) is an indicator used to assess the validity of cognitive test performance. Scores of 7 or lower suggest poor effort or negative response bias. The possibility that RDS scores are also affected by pain has not been addressed thus potentially threatening RDS specificity. The current study used cold pressor-induced pain to investigate the effect of pain on RDS scores. Sixty undergraduate volunteers randomly assigned to one of three conditions (control, simulator, pain) completed the Digit Span subtest from the Wechsler Adult Intelligence Scale-III from which the RDS is derived. No differences in RDS scores were found between the control and pain groups, and neither group scored below 8. Sixty-five percent of the simulator group scored 7 or below. These results suggest that RDS is not affected by pain, and scores of 7 or less in persons with pain can be more confidently attributed to negative response bias.

Blood pressure variability and baroreflex sensitivity of a healthy male during cold pressor test that induced development of neurocardiogenic syncope

BACKGROUND

The cold pressor test (CPT) is a recognized physiological technique to evaluate autonomic cardiovascular function. The present case study assessed the cardiovascular response of a healthy adult male during 3 min of CPT.

METHODS

Heart rate (HR) by single-lead electrocardiography and blood pressure (BP) by an arterial tonometer of the participant on a beat-to-beat basis were recorded before and during CPT.

RESULTS

HR during CPT showed a biphasic pattern with an initial increase from baseline (86 bpm) to the first 30 s of CPT (93 bpm) followed by a decrease. It dropped to 51 bpm during the last 30 s of CPT. Systolic blood pressure (SBP) increased from baseline (110 mmHg) to 1 min (122 mmHg) followed by a decrease. SBP immediately after CPT reduced to 57 mmHg. Diastolic blood pressure (DBP) from baseline (71 mmHg) slightly increased to 75 mmHg up to 90 s of the test, thereafter it registered a fall, and during the last 30 s of CPT, DBP fell to 30 mmHg. Stroke volume increased from baseline (75 mL/min) to the first 30 s (99 mL/min), followed by a slight reduction which was maintained till last of the test (70 mL/min). Cardiac output after an initial increase from baseline (6.4 L/min) to the first 30 s (9.2 L/min) decreased to 4.1 L/min during the last 30 s of the test. Baroreflex sensitivity (BRS) from baseline (9.32 ms/mmHg) plummeted to 6.67 ms/mmHg during the first 30 s of CPT followed by an increase, and after CPT, BRS was increased to 15.23 ms/mmHg. Other cardiovascular parameters such as myocardial contractility (dp/dt), total peripheral resistance, and mean arterial pressure were reduced in the individual at the time of loss of consciousness that occurred at the end of the last 30 s of CPT.

CONCLUSIONS

The present case study described the modulation of cardiovascular functions of a healthy male during CPT, which finally led to the development of neurocardiogenic syncope characterized by hypotension and bradycardia.

Cardiovascular responses during cold pressor test are different in Parkinson disease and multiple system atrophy with parkinsonism

OBJECTIVE

Orthostatic hypotension (OH) is common in Parkinson disease (PD) and multiple system atrophy of parkinsonian type (MSA-P), but the pathophysiology of OH is different in the two. We hypothesised that the baroreflex-independent sympathetic reactivity may also be different in them. To evaluate this we assessed the sympathetic vascular reactivity and the heart rate response to the standard cold pressor test (CPT) in these patients.

METHODS

The study was conducted in ten patients with PD with OH, 5 PD without OH, 13 MSA-P with OH, and 7 MSA-P without OH. Lead II ECG and finger PPG (photoplethysmography) were simultaneously acquired during a baseline period of 1 min followed by a 10 °C cold exposure (1 min) of the contralateral hand (CPT). The vascular response was then evaluated by computing the pulse transit time (PTT).

RESULTS

The percentage decrease in PTT during the CPT was significantly higher in patients with PD as compared to MSA-P, irrespective of the presence or absence of OH (-2.74 ± 0.96 vs -0.05 ± 0.75 %, p = 0.03; PD vs MSA-P with OH and -3.04 ± 0.85 vs 0.48 ± 1.13 %, p = 0.04; PD vs MSA-P without OH). The rise in heart rate during CPT was similar in patients with PD and MSA-P with or without OH (4.95 ± 1.6 vs 5.99 ± 1.04, p = 0.28; PD vs MSA-P with OH and 5.62 ± 1.31 vs 13.15 ± 2.89, p = 0.06; PD vs MSA-P without OH).

INTERPRETATION

Vasoconstrictor response to CPT is compromised in MSA-P as compared to PD, but the baroreflex-independent heart rate response is similar in the two.

Autonomic nervous system and hypothalamic-pituitary-adrenal axis response to experimentally induced cold pain in adolescent non-suicidal self-injury--study protocol

BACKGROUND

Adolescent non-suicidal self-injury (NSSI) is associated with altered sensitivity to experimentally induced pain. Adolescents engaging in NSSI report greater pain threshold and pain tolerance, as well as lower pain intensity and pain unpleasantness compared to healthy controls. The experience of pain is associated with reactivity of both the autonomic nervous system (ANS) and the hypothalamic-pituitary-adrenal (HPA) axis. However, previous research has not yet systematically addressed differences in the physiological response to experimentally induced pain comparing adolescents with NSSI and age- and sex-matched healthy controls.

METHODS/DESIGN

Adolescents with NSSI and healthy controls undergo repeated painful stimulation with the cold pressor task. ANS activity is continuously recorded throughout the procedure to assess changes in heart rate and heart rate variability. Blood pressure is monitored and saliva is collected prior to and after nociceptive stimulation to assess levels of saliva cortisol.

DISCUSSION

The study will provide evidence whether lower pain sensitivity in adolescents with NSSI is associated with blunted physiological and endocrinological responses to experimentally induced pain compared to healthy controls. Extending on the existing evidence on altered pain sensitivity in NSSI, measured by self-reports and behavioural assessments, this is the first study to take a systematic approach in evaluating the physiological response to experimentally induced pain in adolescent NSSI.

TRIAL REGISTRATION

Deutsche Register Klinischer Studien, Study ID: DRKS00007807; Trial Registration Date: 13.02.2015.

Enhanced stress response by a bilateral feet compared to a unilateral hand Cold Pressor Test

The Cold Pressor Test (CPT) is a frequently employed laboratory stress protocol. However, with many experimental designs the application in its classic form (immersion of the dominant hand into ice-water) is problematic as unilateral stimulation may need to be avoided and/or hands are required for further measurements. Here, we describe a simple modification of the classic CPT in which both feet are immersed into ice-water and compare the evoked neuroendocrine stress response to the classic CPT in a within-subjects design. Twenty-four healthy participants were exposed to each of both CPT versions on two subsequent days in randomized order. Heart rate, blood pressure, salivary alpha-amylase and cortisol were measured at baseline and during or after CPT exposition, respectively, along with subjective ratings of pain and stress. The bilateral feet CPT induced marked increases in all measured stress parameters. Moreover, with the exception of blood pressure, autonomic and endocrine responses were enhanced compared to the classic CPT. The bilateral feet CPT thus is a valid and simple modification and may be useful when the application of the classic CPT is unfeasible or a stronger neuroendocrine stress response is of interest.

Autonomic responses to lateralized cold pressor and facial cooling tasks

Asymmetry in central nervous system (CNS) control of autonomic nervous system (ANS) activity, a widely debated topic, was investigated via lateralized presentation of two ANS challenges: cold pressor, which elicits primarily sympathetic activation, and facial cooling, a predominantly vagal task. Seventy-three university students (37 female) engaged in these tasks while cardiovascular and electrodermal measures were acquired. Compared to right-side cold pressor, left cold pressor elicited generally larger cardiac, blood pressure, and skin conductance responses, but did not evoke asymmetric changes in heart rate variability. Facial cooling elicited significant increases in vagally mediated heart rate variability, but they were also not lateralized. These findings are consistent with reports of right hemisphere dominance in sympathetic regulation, but indicate that CNS vagal control is relatively symmetric. These results are framed in terms of polyvagal theory and neurovisceral integration two influential models of CNS-ANS integration in the service of adaptive environmental engagement.

Hyper-arousal decreases human visual thresholds

Arousal has long been known to influence behavior and serves as an underlying component of cognition and consciousness. However, the consequences of hyper-arousal for visual perception remain unclear. The present study evaluates the impact of hyper-arousal on two aspects of visual sensitivity: visual stereoacuity and contrast thresholds. Sixty-eight participants participated in two experiments. Thirty-four participants were randomly divided into two groups in each experiment: Arousal Stimulation or Sham Control. The Arousal Stimulation group underwent a 50-second cold pressor stimulation (immersing the foot in 0-2° C water), a technique known to increase arousal. In contrast, the Sham Control group immersed their foot in room temperature water. Stereoacuity thresholds (Experiment 1) and contrast thresholds (Experiment 2) were measured before and after stimulation. The Arousal Stimulation groups demonstrated significantly lower stereoacuity and contrast thresholds following cold pressor stimulation, whereas the Sham Control groups showed no difference in thresholds. These results provide the first evidence that hyper-arousal from sensory stimulation can lower visual thresholds. Hyper-arousal's ability to decrease visual thresholds has important implications for survival, sports, and everyday life.

Effects of cold pressor stress on the human startle response

Both emotion and attention are known to influence the startle response. Stress influences emotion and attention, but the impact of stress on the human startle response remains unclear. We used an established physiological stressor, the Cold Pressor Test (CPT), to induce stress in a non-clinical human sample (24 student participants) in a within-subjects design. Autonomic (heart rate and skin conductance) and somatic (eye blink) responses to acoustic startle probes were measured during a pre-stress baseline, during a three minutes stress intervention, and during the subsequent recovery period. Startle skin conductance and heart rate responses were facilitated during stress. Compared to baseline, startle eye blink responses were not affected during the intervention but were diminished afterwards. These data describe a new and unique startle response pattern during stress: facilitation of autonomic stress responses but no such facilitation of somatic startle eye blink responses. The absence of an effect of stress on startle eye blink responsiveness may illustrate the importance of guaranteeing uninterrupted visual input during periods of stress.

Reproducibility of blood pressure response to the cold pressor test: the GenSalt Study

An elevated blood pressure (BP) response to the cold pressor test (CPT) is associated with increased risk of hypertension and cardiovascular disease. However, it is still unclear whether BP response to the CPT is a stable and reproducible trait over time. Using the same study protocol, the authors repeated the CPT 4.5 years after initial administration among 568 Han Chinese in rural northern China (2003-2005 and 2008-2009). BP was measured using a standard mercury sphygmomanometer prior to and 0, 1, 2, and 4 minutes after the participants immersed their hand in ice water (3°C-5°C) for 1 minute. Absolute BP levels and BP responses during the CPT in the initial and repeated administrations were highly correlated. For example, the correlation coefficients were 0.67, 0.73, 0.71, and 0.72 for absolute systolic BP levels at 0, 1, 2, and 4 minutes after ice-water immersion (all P 's < 0.0001). The correlation coefficients for systolic BP response were 0.41 at 0 minutes, 0.37 at 1 minute, 0.42 for maximum response, and 0.39 for the area under the curve during CPT (all P 's < 0.0001). These data indicate that BP response to the CPT is a long-term reproducible and stable characteristic in the general population.

Improvement in arousal, visual neglect, and perception of stimulus intensity following cold pressor stimulation

The relationship between arousal, perception, and visual neglect was examined in this case study. Cold pressor stimulation (CPS: immersing the foot in iced water) was used to manipulate arousal and to determine its effects on contralesional neglect, perception of stimulus intensity (magnitude estimation), reaction time, and an electrophysiological correlate of ascending reticular activating system activity (i.e., the P50 potential). Measures that normalized from baseline following CPS included contralesional neglect on a clock drawing test, perception of stimulus magnitude, and P50 amplitude. The P50 amplitude returned to its abnormally low baseline level 20 min after CPS ended, indicating that CPS increased arousal.

Depressive symptoms and attenuated physiological reactivity to laboratory stressors

There is evidence that depressive symptoms are associated with attenuated physiological reactivity to active stressors. However, it is not known whether blunted reactivity in depressed individuals is stressor-specific. We examined cardiovascular and electrodermal reactivity in non-clinical participants with varying levels of depressive symptoms to different active and passive stressors. Depressive symptoms were inversely related to both blood pressure and skin conductance reactivity during a public speaking task and the viewing of the speech video. However, no effects were found during a cold pressor task. Together these findings suggest that depressive symptoms are related to attenuated sympathetic nervous system reactivity in response to self-relevant stressors.

Acute exercise improves endothelial function despite increasing vascular resistance during stress in smokers and nonsmokers

The present study examined the effect of acute exercise on flow mediated dilation (FMD) and reactivity to neurovascular challenges among female smokers and nonsmokers. FMD was determined by arterial diameter, velocity, and blood flow measured by Doppler ultrasonography after forearm occlusion. Those measures and blood pressure and heart rate were also assessed in response to forehead cold and the Stroop Color-Word Conflict Test (CWT) before and after 30 min of rest or an acute bout of cycling exercise (∼50% VO₂ peak). Baseline FMD and stress responses were not different between smokers and nonsmokers. Compared to passive rest, exercise increased FMD and decreased arterial velocity and blood flow responses during the Stroop CWT and forehead cold in both groups. Overall, acute exercise improved endothelial function among smokers and nonsmokers despite increasing vascular resistance and reducing limb blood flow during neurovascular stress.

The Effects of Nature Images on Pain in a Simulated Hospital Patient Room

Background:

Views of nature have been reported to relieve stress and pain, making nature an ideal medium for use in healthcare settings. In hospitals whose design does not allow for a view of nature, virtual and surrogate views of nature may be viable therapeutic options.

Objective:

This study tests the effects of specific nature images, as defined by Appleton's prospect refuge theory of landscape preference, on participants experiencing pain. The hypotheses were: (1) Nature views are variable in their impact on specific psychological and physiological health status indicators; and (2) Prospect and refuge nature scenes are more therapeutic than hazard nature scenes. The research question was (1) Which nature image categories are most therapeutic as evidenced by reduced pain and positive mood?

Methods:

An experiment using mixed methods assessed the effects of four different nature scenes on physiological (blood pressure, heart rate) and psychological (mood) responses when a person was subjected to a pain stressor. Four groups were subjected to a specific nature image category of prospect, refuge, hazard, or mixed prospect and refuge; the fifth group viewed no image. The Short-Form McGill Pain Questionnaire and the Profile of Mood States survey instruments were used to assess pain and mood, respectively. Continuous physiological readings of heart rate and blood pressure were collected. Pain was induced through a cold pressor task, which required participants to immerse their nondominant hand in ice water for up to 120 seconds.

Results:

The mixed prospect and refuge image treatment showed significantly lower sensory pain responses, and the no-image treatment indicated significantly higher affective pain perception responses. The hazard image treatment had significantly lower diastolic blood pressure readings during the pain treatment, but it also had significantly high total mood disturbance.

Conclusions:

Although there was no clear “most” therapeutic image, the mixed prospect and refuge image showed significant potential to reduce sensory pain. The hazard image was the most effective at distracting participants from pain, but it should not be considered a positive distraction because it also received the highest mood disturbance scores of all groups.

The Relationship of Low Birth Weight to Blood Pressure, Cortisol Levels, and Reactivity in African American Adolescents: A Pilot Study

Epidemiological studies show a relationship between low birth weight (LBW) and adult cardiovascular disease. Blood pressure and cortisol hyper-responsiveness during physiologic stress may function as biological markers for hypertension. The purpose of this study was to explore the relationship of blood pressure and cortisol levels with induced physiologic stress to LBW. Forty-eight adolescents, 14 to 16 years old, were tested for blood pressure and cortisol levels at rest and in response to a physiological stressor. A history of LBW was obtained. Multivariate repeated measures analysis and chi-square analyses were used to determine the changes in blood pressure and cortisol.Forty-eight African American adolescents, mean age 14.98 years (SD = 0.33), completed the study. Thirteen adolescents (27%) reported LBW. Although not statistically significant, systolic and diastolic pressures were 6 mmHg and 2 mmHg, respectively, higher in the LBW group when compared with the normal birth weight (NBW) group (p = 0.33 and p = 0.21, and 6 (46%) had elevated blood pressures (p = 0.005)). Blood pressure changes, cardiovascular reactivity, elevated blood, or all of these were significantly higher in LBW African American adolescents (p = 0.006). Cardiovascular reactivity was not significant (p = 0.208)). The mean average cortisol levels were (18.8 nmol/dL (SD = 11.0) but comparable (p = 0.72)). The number of LBW adolescents with cortisol reactivity was significantly higher that in the NBW group (p = 0.041). This study adds support to the association of LBW to biological markers of hypertension in childhood.

Circadian Variation in Cortisol Reactivity to an Acute Stressor

To investigate the role of the circadian pacemaker in cortisol reactivity to a cold pressor challenge, 26 diurnally subjects participated in a constant-routine protocol and were divided into two groups. Group 1 started immediately after a monitored sleep period at 09:00 h, while group 2 started 12 h later. After 2 h of adaptation, a cold pressor test was presented every 3 h. The cortisol response was assessed by means of saliva samples that were taken before and after the test. The pretest samples were considered to be base-rate measures and base-rate values as subtracted from post-test values were considered as reactivity measures. Both measures showed distinct Time-of-Day variations (respectively: F(7,168) = 16.92, p < 0.001, epsilon = 0.383; and F(7,175) = 8.01, p < 0.001, epsilon = 0.523). These findings are interpreted as evidence for the existence of an endogenous circadian periodicity underlying the sensitivity of the hypothalamus-pituitary-adrenal (HPA)-axis to acute stress.

Effects of low ambient temperature on heart rate variability during sleep in humans

The effects of cold exposure on heart rate variability (HRV) during sleep were examined. Eight male subjects slept under three different conditions: 3 degrees C, 50-80% relative humidity (RH) [3]; 10 degrees C, 50% RH [10]; and 17 degrees C 50% RH [17]. No significant differences were observed in HRV during rapid eye movement sleep (REM) and wakefulness. The ratio of the low frequency (LF) to high frequency component (HF) of HRV (LF/HF) significantly differed among the conditions during stage 2 and slow wave sleep (SWS) that decreased as the ambient temperature decreased. The normalized LF [LF/(LF + HF)] significantly decreased in 3 and 10 than in 17 during SWS. In low ambient temperature, predominant cardiac parasympathetic activity during stage 2 with no significant difference during REM and wakefulness may cause variations in HRV at transition from stage 2 to REM and wakefulness. These results may partly explain the peak in adverse cardiac events during winter.

Stress and health: psychological, behavioral, and biological determinants

Stressors have a major influence upon mood, our sense of well-being, behavior, and health. Acute stress responses in young, healthy individuals may be adaptive and typically do not impose a health burden. However, if the threat is unremitting, particularly in older or unhealthy individuals, the long-term effects of stressors can damage health. The relationship between psychosocial stressors and disease is affected by the nature, number, and persistence of the stressors as well as by the individual's biological vulnerability (i.e., genetics, constitutional factors), psychosocial resources, and learned patterns of coping. Psychosocial interventions have proven useful for treating stress-related disorders and may influence the course of chronic diseases.

Autonomic characteristics of defensive hostility: reactivity and recovery to active and passive stressors

The autonomic characteristics of hostility and defensiveness were assessed in 55 male undergraduates based on composite Cook Medley Hostility (Chost) and Marlowe Crowne Social Desirability (MC) scores to create 4 groups: Defensive Hostile (DH; high MC, high Chost), High Hostile (HH; low MC, high Chost), Defensive (Def; high MC, low Chost) and Low Hostile (LH; low MC, low Chost). All subjects engaged in a video game (VG) and hand cold pressor (CP) task. Cardiovascular responses in DH subjects were predicted to show enhanced sympathetic alpha and beta-adrenergic activity and the least vagal control compared to others across tasks. DH and LH men showed significant heart rate reactivity to the CP task compared to HH men. LH men showed significant reductions in high frequency power (vagal assessment) to the tasks compared to HH men. Future studies may employ harassment techniques and include the factors of gender and ethnicity in their assessments.

Pain, Malingering, and Performance on the WAIS-III Processing Speed Index

Pain patients often report cognitive symptoms and many will include them in their claims of disability. The Processing Speed Index (PSI) of the WAIS-III was investigated as one aspect of cognitive functioning in six groups. Slight impairment was found for PSI and Digit Symbol subtest performance, but not for Symbol Search, in a Laboratory-induced Pain group and a Clinical Pain group. The lowest scores were found in a Simulator group instructed to fake cognitive impairment and a Clinical Pain group diagnosed as Malingering. Results suggest that PSI scores are only slightly reduced by laboratory-induced pain or chronic pain, and that unexpectedly low scores in the absence of significant/documented brain dysfunction suggest poor effort or deliberate misrepresentation.

The relationship of blood pressure and cortisol reactivity to family history of hypertension of African American adolescents

Ethnicity and family history of hypertension (FHH) have been associated with the development of hypertension. Blood pressure and cortisol reactivity during physiologic stress are hypothesized to function as biologic markers for hypertension. The purpose of this study was to explore the relationship of blood pressure and cortisol reactivity physiologic to FHH in a selected sample of African American adolescents.

METHODS

Demographic data and physiologic measurements were obtained from 48 African American adolescents (14-17 years). Reactivity was induced by a cold pressor test of hand immersion in cold water. chi, t tests, and multivariate repeated-measures analysis were used to determine relationships.

RESULTS

Thirty-one (65%) subjects reported an FHH. Thirty (63%) subjects demonstrated cardiovascular reactivity. Although the mean systolic blood pressure was 4 mm Hg higher, t tests indicated no significance between group in systolic blood pressure (P = .32), diastolic pressure (P = .73), and cortisol (P =.81). Blood pressure reactivity of the FHH group was significantly different than the no family history group (P = .0338). Cortisol levels for the total group were markedly elevated (19 nmol/dL) and there was no significant difference in reactivity.

CONCLUSION

African American adolescents with FHH demonstrate increased blood pressure reactivity. Cortisol levels were elevated for all participants. This study adds support to the association of blood pressure reactivity, a biologic marker of HTN and FHH.

Hostility and sex differences in the magnitude, duration, and determinants of heart rate response to forehead cold pressor: Parasympathetic aspects of risk

Recent models hypothesize that hostility confers increased risk of CHD through weaker parasympathetic dampening of cardiovascular reactivity (CVR). We tested this possibility using the forehead cold pressor task, a common maneuver which elicits the "dive reflex" characterized by a reflexive decrease in HR presumably through cardiac-parasympathetic stimulation. Participants were initially chosen from the outer quartiles of a sample of 670 undergraduates screened using the hostility subscale of the Aggression Questionnaire ([Buss, A.H., Perry, M., 1992. The Aggression Questionnaire. Journal of Personality and Social Psychology, 63, 452-459.]). The final sample of 80 participants was evenly divided between men and women and high and low hostility. Following a 10-min baseline, participants underwent a 3-min forehead cold pressor task. The task evoked a significant HR deceleration that was mediated by PNS activation, as assessed by respiratory sinus arrhythmia (RSA). Replicating prior research, men displayed greater decrease in HR. More important, low hostiles maintained larger HR deceleration over time compared to high hostiles although the autonomic basis for this effect was unclear. The findings broaden understanding of hostility and sex-related cardiovascular functioning and support the task as a method for evoking PNS-cardiac stimulation.

Pain related recall predicts future pain report

It is frequently necessary for patients to undergo multiple painful medical interventions as part of their diagnosis and care. Predictors of future pain report have yet to be established although initial pain level, affect, and memory of the procedure are often implicated. The purpose of this research was to establish a predictive model of future pain reporting using a standardized experimental pain stimulus. Forty-three healthy subjects completed an initial forehead cold pressor task (Session 1) and an identical task nine months later (Session 2). Subjects also provided retrospective pain evaluations six months after Session 1. Hierarchical regression was used to identify predictors of Session 2 maximum pain intensity. Fifty-six percent of the total variance (p < .01) was accounted when Session 1 maximum pain intensity, Session 1 negative affect, and remembered maximum pain intensity were loaded together in the model. Only 1% of the variance was uniquely accounted by Session 1 maximum pain intensity (p = .38) while remembered maximum pain intensity uniquely accounted for 25% of the variance (p < or = .01) and Session 1 negative affect uniquely accounted for 17% of the variance (p < or = .01). An additional 13% of the variance was shared between Session 1 maximum pain intensity and remembered maximum pain intensity. The level of remembered Session 1 pain was significantly exaggerated from the initial pain report (p < or = .05) but not significantly different from the level of pain reported at Session 2. These findings provide strong evidence for a post-pain modulation phenomenon in which cognitive processes influence both pain recall and future pain reporting.

Cardiovascular reactivity in cardiovascular disease: "once more unto the breach"

Discussed here are conceptual and methodologic issues that bear on the role of behaviorally evoked cardiovascular reactivity in cardiovascular disease. It is argued that recent criticisms concerning the validity of cardiovascular reactivity as a stable dimension of individual differences arise from inadequacies of measurement prevalent in prior literature. With standardization of test stimuli and application of psychometric principles lo protocol development, assessment of reactivity are found to be highly reliable and, in turn, to demonstrate the dispositional nature of this construct. Recent studies also document an underlying heterogeneity of hemodynamic reactions to stress, with distinct cardiac and vascular components. Because hemodynamic adjustments show some plasticity under differing task conditions, responses seen in particular contexts reflect influences of both an individual-specific response potential and response-eliciting properties of the stimulus. On the question of disease relevance, it is concluded that cardiovascular reactivity cannot yet be considered an established risk factor for either coronary heart disease or hypertension. However, the preponderance of existing clinical, experimental. and epidemiologic evidence is consistent with such an association and warrants further study in the context or population-based, prospective investigation.

Pain, malingering and the WAIS-III Working Memory Index

BACKGROUND CONTEXT

Pain patients often report cognitive symptoms, and many will include them in their claims of disability. There is empirical evidence that patients with pain do experience problems on attention-demanding cognitive tasks, but the results are mixed and the potential impact of exaggeration in the context of pain-related litigation has not been addressed.

PURPOSE

1) Examine the impact of pain and malingering on attention; 2) determine if the Working Memory Index (WMI) of the Wechsler Adult Intelligence Scale-3 (WAIS-III) can reliably detect malingering.

STUDY DESIGN/SETTING

Study 1: simulator design; Study 2: clinical known-groups design.

PATIENT SAMPLE

Study 1 used healthy college students; Study 2 used chronic pain patients and neurological patients.

OUTCOME MEASURES

The WMI and its constituent subtests.

METHODS

Study 1: College students were administered the WMI under three conditions: standard administration, with cold-pressor induced pain, or with instructions to simulate impairment due to pain. Study 2: Known-groups design in which the WMI was examined in non-malingering and definite malingering chronic pain patients, non-malingering moderate-severe traumatic brain injury, and memory disorder patients seen for routine psychological evaluation. Malingering was operationalized using published criteria.

RESULTS

There were no group differences in WMI or its subtests among non-malingering groups, but some individual clinical patients with pain did score at a level suggestive of attentional impairment. The lowest scores were found in the simulated malingering college students and definite malingering clinical pain groups, in which about half scored worse than 95% of the non-malingering clinical patients.

CONCLUSIONS

This study demonstrated that even when controlling for exaggeration some pain patients do exhibit problems with attentional function. However, significant impairment in WMI performance (eg, index score<or=70), particularly in the absence of brain dysfunction, cannot reasonably be attributed to the effects of either acute or chronic pain, even at moderate to severe levels, and likely reflects intentional exaggeration.

Idiodynamic profiles of cardiovascular activity: A P-technique approach

A study was conducted to expand the conventional view of cardiovascular (CV) reactivity by using the idiodynamic paradigm for investigation of individuals. Patterns of autonomic CV regulation were assessed in six subjects across diverse laboratory tasks on three separate occasions. Individual CV profiles were derived from these data with P-technique factor analysis, and then group aggregated with chain P-technique. The composite pattern suggested a three-component solution consisting of cardiac rate, cardiac contractility, and peripheral resistance factors. Individual profiles were compared to the composite pattern; these profiles differed in the number of components derived, percentage variance explained by these components, and relative dominance of specific CV components. A hypothesis that emerged is that the subjects differed in the complexity of CV control. It appears that the idiodynamic framework, combined with novel research designs and statistical methods, may help expand the view of CV reactivity beyond the traditional unitary view as response magnitude.

Prostaglandin modulation of venoconstriction to physiological stress in normals and heart failure patients

Prostaglandins released from blood vessels modulate vascular tone, and inhibition of their production during exogenous infusions of catecholamines causes increased venoconstriction. To determine the influence of prostaglandin production on venoconstriction during physiological stimuli known to cause sympathetic activation, and to assess its importance in chronic heart failure (CHF), we studied 11 normal subjects (62 +/- 4 yr) and 14 patients with CHF (64 +/- 2 yr, left ventricular ejection fraction 23 +/- 1%, New York Heart Association classes II and III) (means +/- SE). Dorsal hand vein distension was measured during mental arithmetic (MA), cold pressor test (CPT), and lower body negative pressure (LBNP; -10 and -40 mmHg), with saline infusion in one hand and local indomethacin (cyclooxygenase inhibitor) infusion (3 microg/min) in the other. Acetylcholine (0.01-1 nmol/min) dilated veins preconstricted with PGF(2alpha) in normals but, consistent with endothelial dysfunction, barely did so in CHF patients (P = 0.001). Nonendothelial venodilation to sodium nitroprusside (0.3-10 nmol/min) was not different between normals and CHF patients. Resting venous norepinephrine levels were higher in CHF patients (2,812 +/- 420 pmol/l) than normals (1,418 +/- 145 pmol/l, P = 0.007). In normals, indomethacin caused increased venoconstriction to MA (from 4.9 +/- 1.5 to 19.2 +/- 4.5%, P = 0.022) and CPT (from 2.9 +/- 3.8 to 17.6 +/- 4.2%, P = 0.007). In CHF, indomethacin caused increased venoconstriction to MA (from 6.6 +/- 3.9% to 19.0 +/- 4.5%, P = 0.014), CPT (from 9.6 +/- 2.1% to 20.1 +/- 3.7%, P = 0.001), and -40 mmHg LBNP (from 10.7 +/- 3.0% to 23.2 +/- 3.8%, P = 0.041). Control responses for all tests were not different between normals and CHF patients. The effects of indomethacin on venoconstriction to MA and CPT were not different between normals and CHF patients, but venoconstriction to -40 mmHg LBNP was accentuated in CHF patients (P = 0.036). Inhibition of prostaglandins by indomethacin significantly enhances hand vein constriction to physiological stimuli in both normals and CHF patients, although a differential effect exists for LBNP.