Cold Pressor Test Research Articles

Investigating mortality salience as a potential causal influence and moderator of responses to laboratory pain.

Because pain can have profound ramifications for quality of life and daily functioning, understanding nuances in the interplay of psychosocial experiences with pain perception is vital for effective pain management. In separate lines of research, pain resilience and mortality salience have emerged as potentially important psychological correlates of reduced pain severity and increased tolerance of pain. However, to date, there has been a paucity of research examining potentially interactive effects of these factors on pain perception. To address this gap, the present experiment investigated mortality salience as a causal influence on tolerance of laboratory pain and a moderator of associations between pain resilience and pain tolerance within a Chinese sample. Participants were healthy young Chinese adults (86 women, 84 men) who first completed a brief initial cold pressor test (CPT) followed by measures of demographics and pain resilience. Subsequently, participants randomly assigned to a mortality salience (MS) condition completed two open-ended essay questions in which they wrote about their death as well as a death anxiety scale while those randomly assigned to a control condition completed analogous tasks about watching television. Finally, all participants engaged in a delay task and a second CPT designed to measure post-manipulation pain tolerance and subjective pain intensity levels. MS condition cohorts showed greater pain tolerance than controls on the post-manipulation CPT, though pain intensity levels did not differ between groups. Moderator analyses indicated that the relationship between the behavior perseverance facet of pain resilience and pain tolerance was significantly stronger among MS condition participants than controls. This experiment is the first to document potential causal effects of MS on pain tolerance and Ms as a moderator of the association between self-reported behavior perseverance and behavioral pain tolerance. Findings provide foundations for extensions within clinical pain samples.

351 Can Exogenous Ketones Prevent the Effects of High Salt Intake on Renal Vascular Resistance During Sympathoexcitation?

OBJECTIVES/GOALS: Renal vascular resistance (RVR) is the opposition to blood flow by renal arteries. At the population level, dietary salt increases RVR and blood pressure (BP), which are associated with cardiovascular disease. Recent data indicate exogenous ketones may offset adverse cardiorenal effects of salt. METHODS/STUDY POPULATION: Our registered clinical trial (NCT05545501) is a double-blinded, placebo-controlled, crossover study. Participants are being randomized to three 10-day conditions: A) control; B) high salt; C) high salt and ketone supplementation. Ten participants are enrolled (target 30 participants). Renal blood velocity (RBV) in the renal and segmental arteries will be measured in the decubitus position using Doppler ultrasound during a 3-minute baseline and 3-minute cold pressor test. We will measure brachial BP with an automated oscillometric BP monitor. RVR will be calculated as mean BP divided by RBV. Statistical analyses will include ANOVA and correlations with α set at ≤ 0.05. RESULTS/ANTICIPATED RESULTS: We anticipate attenuated RBV and increased BP during the cold pressor test, particularly following high salt loading, leading to greater RVR. We hypothesize ketone supplementation will attenuate the high salt induced increase in RVR during the cold pressor test. In addition to RVR we will examine renal vascular conductance which is the ease with which blood flows through arteries, calculated as RBV divided by mean BP. Additional hemodynamics such as heart rate and systolic and diastolic BP will be reported and correlated with primary outcomes. DISCUSSION/SIGNIFICANCE: Dietary salt plays a role in hypertension, cardiovascular disease, and chronic kidney disease, which are leading causes of death. Ketone supplementation may be a promising approach to counteract the detrimental effects of high dietary salt and improve cardiovascular health in adults.

The Effectiveness of Hypnoanalgesia Using Conventional and Placebo Hypnosis Induction

The effectiveness of hypnosis-based pain management is well-established. However, mechanisms of action and specific effective components are not well understood. The sociocognitive theory of hypnosis proposes that the effectiveness of hypnosis for pain management is determined by the nonspecific features of response expectancy and context. We tested this claim by contrasting the effectiveness of 2 hypnoanalgesia procedures in a within subjects design using the cold pressor task. The 2 procedures were identical, including analgesic suggestions, except for the hypnosis induction used. One condition involved a well-established hypnosis induction, including suggestions for focused attention, relaxation, and deepening. The other condition included a sham induction procedure using only white noise. In our confirmatory analysis (N = 46), we found that pain tolerance increased compared to baseline equivalently in the conventional and sham induction conditions (mean increase 13.7 and 12.4 seconds respectively, average within subject difference −1.27 seconds, 90% confidence interval [CI] = −8.46, 5.90). This finding supports the claim of the sociocognitive theory considering that response expectancy for pain reduction was also equivalent between the conditions (average difference 2.30, 90% CI = −2.23, 6.84). However, self-reported hypnosis depth was greater in the conventional induction condition (average difference −.78, 90% CI: −1.36, −.07), which contradicts sociocognitive predictions. Our findings indicate that conventional procedural elements of hypnosis inductions, such as suggestions for focused attention, relaxation, and deepening, may not be necessary to achieve acute pain reduction in an experimental setting when the hypnosis intervention includes analgesic suggestions. PerspectiveThis study assessed the necessary effective components of hypnosis-based analgesia interventions. Our findings suggest that procedural features such as suggestions for focused attention, relaxation, and deepening may not be necessary for hypnoanalgesia as long as pain relief suggestions are present, and the hypnosis context and response expectancy are established. Trial registrationThis trial was registered on Open Science Framework with the registry number e96xk, available at https://osf.io/e96xk.

359 Low-Intensity Focused Ultrasound to Human Dorsal Anterior Cingulate Cortex and Insula Attenuates Measures of Central Sensitization

INTRODUCTION: Central sensitization is the abnormal amplified response to pain and is associated with chronic pain. Increased insula and dorsal anterior cingulate cortex (dACC) activity is associated with central sensitization. Low-intensity focused ultrasound (LIFU) is a novel form of non-invasive neuromodulation that can precisely target the anterior insula (AI), posterior insula (PI) and dACC. METHODS: N = 18 healthy participants underwent conditioned pain modulation (CPM) and temporal summation of pain (TSP) tasks before and after 10 minutes of LIFU or sham stimulations. For CPM, the conditioning stimulus (CS) was a cold pressor test to the left hand and the test stimulus (TS) was a brief transient heat stimulus to the dorsum of the right hand. For TSP, 10 transient heat stimuli (>0.33 Hz) were administered to the dorsum of the right hand. The primary outcome measure for both tasks was perceived pain ratings (0-9). Electrodermal response and electrocardiogram was collected to evaluate the effect of LIFU on autonomic reactivity. RESULTS: LIFU to PI increased CPM 0.5 ± 0.181 compared to sham (p = 0.024). LIFU to PI also significantly reduced perceived pain during the TSP task compared to sham (p < 0.001). We also found a significant difference between dACC and sham conditions during TSP by -0.55 ± 0.05 (p < 0.001). LIFU to the AI increases frequency domain measures of heart-rate variability. CONCLUSIONS: LIFU to the insula and dACC affects pain processing in measures of central sensitization. This demonstrates the neuromodulation abilities of LIFU and is a promising tool to develop noninvasive clinical therapies for chronic pain conditions.

Consistently increased dorsolateral prefrontal cortex activity during the exposure to acute stressors.

Stress has a major impact on our mental health. Nonetheless, it is still not fully understood how the human brain responds to ongoing stressful events. Here, we aimed to determine the cortical dynamics during the exposure to ecologically valid, standardized stressors. To this end, we conducted 3 experiments in which healthy participants underwent the Trier Social Stress Test (experiments 1 and 2) and the Socially Evaluated Cold Pressor Test (experiment 3) or a respective control manipulation, while we measured their cortical activity using functional near-infrared spectroscopy. Increases in salivary cortisol and subjective stress levels confirmed the successful stress induction in all experiments. Results of experiment 1 showed significantly increased cortical activity, in particular in the dorsolateral prefrontal cortex, during the exposure to the Trier Social Stress Test. Experiment 2 replicated this finding and showed further that this stress-related increase in dorsolateral prefrontal cortex activity was transient and limited to the period of the Trier Social Stress Test. Experiment 3 demonstrated the increased dorsolateral prefrontal cortex activity during the Socially Evaluated Cold Pressor Test, suggesting that this increase is generalizable and not specific to the Trier Social Stress Test. Together, these data show consistently that dorsolateral prefrontal cortex activity is not reduced, as commonly assumed, but increased under stress, which may promote coping with the ongoing stressor.

Renal vascular control during normothermia and passive heat stress does not differ between healthy younger men and women.

Men are likely at greater risk for heat-induced acute kidney injury compared with women, possibly due to differences in vascular control. We tested the hypothesis that the renal vasoconstrictor and vasodilator responses will be greater in younger women compared with men during passive heat stress. Twenty-five healthy adults [12 women (early follicular phase) and 13 men] completed two experimental visits, heat stress or normothermic time-control, assigned in a block-randomized crossover design. During heat stress, participants wore a water-perfused suit perfused with 50°C water. Core temperature was increased by ∼0.8°C in the first hour before commencing a 2-min cold pressor test (CPT). Core temperature remained clamped and at 1-h post-CPT, subjects ingested a whey protein shake (1.2 g of protein/kg body wt), and measurements were taken pre-, 75 min, and 150 min post-protein. Beat-to-beat blood pressure (Penaz method) was measured and segmental artery vascular resistance (VR, Doppler ultrasound) was calculated as segmental artery blood velocity ÷ mean arterial pressure. CPT-induced increases in segmental artery VR did not differ between trials (trial effect: P = 0.142) nor between men (heat stress: 1.5 ± 1.0 mmHg/cm/s, normothermia: 1.4 ± 1.0 mmHg/cm/s) and women (heat stress: 1.4 ± 1.2 mmHg/cm/s, normothermia: 2.1 ± 1.1 mmHg/cm/s) (group effect: P = 0.429). Reductions in segmental artery VR following oral protein loading did not differ between trials (trial effect: P = 0.080) nor between men (heat stress: -0.6 ± 0.8 mmHg/cm/s, normothermia: -0.6 ± 0.6 mmHg/cm/s) and women (heat stress: -0.5 ± 0.5 mmHg/cm/s, normothermia: -1.1 ± 0.6 mmHg/cm/s) (group effect: P = 0.204). Renal vasoconstrictor responses to the cold pressor test and vasodilator responses following an oral protein load during heat stress or normothermia do not differ between younger men and younger women in the early follicular phase of the menstrual cycle.NEW & NOTEWORTHY The mechanisms underlying greater heat-induced acute kidney injury risk in men versus women remain unknown. This study examined renal vascular control, including both vasodilatory (oral protein load) and vasoconstrictor (cold presser test) responses, during normothermia and heat stress and compared these responses between men and women. The results indicated that in both conditions neither renal vasodilatory nor vasoconstrictor responses differ between younger men and younger women.

Wearables Cardiovascular Monitoring: Effects of Cold Pressor Test on Heart Rates Estimated From ECG, PPG and IPG Signals

Wearables Cardiovascular Monitoring: Effects of Cold Pressor Test on Heart Rates Estimated From ECG, PPG and IPG Signals

Acute stress does not modulate selective attention in a composite letter task

Acute stress has been demonstrated to affect a diverse array of attentional processes, one of which is selective attention. Selective attention refers to the cognitive process of deliberately allocating attentional resources to a specific stimulus, while ignoring other, distracting stimuli. While catecholamines have been shown to narrow attention, investigations on the influence of the stress hormone cortisol have yielded ambiguous results. We conducted two separate studies utilizing different laboratory stress induction paradigms to examine if cortisol influences the ability to selectively attend to local or global elements of a visual stimulus. In Study 1, 72 healthy young men took part either in the stressful Socially Evaluated Cold Pressor Test (SECPT) or a non-stressful (warm water) control, before being exposed to a composite letter task (CLT). Study 2 comprised a sample of 72 healthy young men and women and made use of a modified version of the Trier Social Stress Test (TSST) as well as a non-stressful control version, the friendly-TSST (f-TSST). Via endocrine, physiological, and subjective markers, we confirmed a successful stress induction. As verified with Bayesian statistics, stress did not affect selective attention in neither of the two studies. Furthermore, we were able to replicate the previously demonstrated absence of global precedence for composite figures composed of letters. Our results offer novel insights into the temporal dynamics of the effects of acute stress on attentional processes. Future studies should manipulate the timing of stress induction and investigate the effects of stress on letter vs. non-letter composite figures to shed further light on the underlying mechanisms.

Triggered by your heart: Effects of cardioafferent traffic and stress on automatic responses in a Simon task.

Variations in cardioafferent traffic are relayed to the brain via arterial baroreceptors and have been shown to modulate perceptual processing. However, less is known about the cognitive-behavioral consequences of these effects and their role during stress. Here, we investigated in how far automatic responses during the Simon task were modulated by exposure to a laboratory stressor and the different phases of the cardiac cycle. In this study, 30 participants performed three blocks of a combined horizontal and vertical Simon task, which is characterized by either sensorimotor or cognitive response conflicts, respectively. Before each block, subjects were exposed to both the cold pressor test (CPT) and a control condition according to a within-subjects design. Target stimuli were presented during either systole or diastole. Behavioral and EEG-correlates of task processing were assessed along with subjective, cardiovascular, and endocrine measures of stress. The stress induction was successful yielding significant increases in all these measures compared to control. Moreover, we found the expected Simon effects: in incompatible compared to compatible trials performance was decreased and LRP latency as well as anterior N2 area increased. Importantly, accuracy was improved in compatible but reduced in incompatible trials during systole vs. diastole but only in the horizontal Simon condition. Stress dampened N2 area, however, no interactions with cardiac cycle were evident. These results indicate a faciliatory effect of cardioafferent traffic on automated sensorimotor processes.

Concurrent validity of dynamic bedside quantitative sensory testing paradigms in breast cancer survivors with persistent pain.

Studies on the concurrent validity of clinically applicable testing protocols for conditioned pain modulation (CPM) and temporal summation of pain (TSP) in breast cancer survivors (BCS) with persistent pain are lacking. This study investigated the concurrent validity of two bedside protocols for CPM and TSP in comparison to a respective reference protocol. The participants' preferences for bedside CPM and TSP protocols were assessed. Thirty BCS experiencing persistent pain were included in this study. Each participant underwent a reference test along with two bedside alternatives for assessing both TSP and CPM. For CPM, a cold pressor test (CPT) and blood pressure cuff (BPC) were used as conditioning stimulus. The test stimulus was elicited in parallel by pressure pain threshold after 45 and 90 s of conditioning at the lower limb. The CPM reference test consisted of parallel heat stimuli at the forearms using a two-thermode system. TSP was elicited using a von Frey monofilament (256 mN) and an algometer (98 kPa) at the affected site and opposite lower limb. The TSP reference test consisted of heat stimuli at the affected site and opposite lower limb. Participants' testing preference was examined using a purpose-designed questionnaire. Spearman's rank test examined the correlation between protocols. The two bedside CPM protocols were strongly correlated (r = 0.787-0.939, p < 0.005). A strong correlation was found between the BPC protocol and reference test using the relative effect magnitude (r = 0.541-0.555, p < 0.005). The bedside TSP protocols were moderately correlated with each other only at the lower limb using absolute change scores (r = 0.455, p = 0.012). No significant correlation was found between the bedside and reference TSP protocols. The significantly moderate to very strong correlations between the bedside protocols validate their interchangeability. Researchers and clinicians should be able to choose which bedside protocol they utilize; however, participants favored the use of a BPC and algometer for the evaluation of CPM and TSP, respectively.

Systemic and ocular pressure changes following sympathetic activation in yoga practitioners - A comparative study

Introduction and Aim: Blood Pressure (BP), Intraocular Pressure (IOP) and Ocular Perfusion Pressure (OPP) are precursor parameters that lead to development of glaucoma. Under conditions of stress, either physical or psychological origin, there is disturbance of autonomic regulation. This causes increased activation of the sympathetic nervous system which might influence BP and ocular pressures. An altered autonomic balance towards lower sympathetic drive is observed in subjects practicing yoga, but it is not clear whether this adaptation also influences ocular pressures. Our study attempted to analyze variations in BP, IOP and OPP following sympathetic activation in yogic practitioners and non-practitioners of yoga. Materials and Methods: One hundred and ten subjects aged 18 - 25 years were recruited and categorised into yoga and non-yoga group. Basal BP was recorded using a sphygmomanometer and IOP was recorded using a rebound tonometer. Isometric hand grip (IHG) and Cold pressor test (CPT) were administered one at a time. IOP and BP were recorded immediately following these sympathetic activation tests. Mean arterial pressure and OPP was calculated using standard formula. Results: Significant increase in the values of pulse, BP, IOP and OPP following sympathetic activation were observed in the non-yoga group which was not noted in the yoga group. Elevation in systemic and ocular pressures following sympathetic activation was less in yoga practitioners. This adrenergic response was greater in the non-yoga group. Conclusion: Regular yoga practice maintains adequate perfusion of ocular tissues by autoregulation. Hence yoga can be recommended as a complementary health approach for the autonomic nervous system imbalance.

Trauma film viewing and intrusive memories: Relationship between salivary alpha amylase, endocannabinoids, and cortisol

The endogenous cannabinoid (ECB) system is a small molecule lipid signalling system that is involved in stress response activation and is associated with PTSD, but it is unclear whether salivary ECBs are part of the sympathetic nervous system response to stress. We conducted an adapted trauma film paradigm, where participants completed a cold pressor test (or control) while watching a 10-minute trauma film. We also collected saliva and hair samples and tested them for ECBs, cortisol, and salivary alpha amylase (sAA). As hypothesised, there were significant positive correlations between sAA activity and salivary ECB levels, particularly 2-arachidonoyl glycerol (2-AG), though ECBs were not correlated with sAA stress reactivity. Participants who had a significant cortisol response to the trauma film/stressor reported less intrusive memories, which were also less distressing and less vivid. This effect was moderated by arachidonoyl ethanolamide (AEA), where decreases in AEA post-stress were associated with more intrusive memories in cortisol non-responders only. This study provides new evidence for the role of ECBs in the sympathetic nervous system.

The relationship of pain intensity and opioid craving with delayed methadone dose: A preliminary study of individuals with opioid use disorder.

Despite a strong theoretical link between opioid craving and pain, little is known about the temporal relationship between pain and craving and the acute experience of pain in the context of methadone treatment. Using a cross-over design, the current study evaluated the time course of pain and craving and objective experience of pain as a function of the last methadone dose. Participants (n = 20) presented for the study in the morning and either received methadone dose as scheduled or delayed dose until the afternoon. During the 4-h study visit, participants completed a series of tasks, including repeated assessment of pain and craving at 0, +40, +70, +130, +160 and +240 min and a cold pressor test (CPT) at +15 and +220 min. Separate mixed model results demonstrated no effect of dosing condition on craving; however, there was a significant dosing condition by time interaction (F(5,209) = 3.38, P = .006) such that pain increased over time in the delayed methadone condition but decreased in time in the scheduled methadone condition. A mixed model predicting self-reported pain revealed a three-way interaction between dosing condition, craving and time (F(5,197) = 2.39, P = .039) explained by a positive association between craving and pain at each time point (except 240 min) in delayed condition (P-range = .004-.0001). A separate mixed model on CPT data indicated a significant condition by time interaction such that pain threshold decreased in the delayed, but not scheduled, condition (F(1,57) = 4.01, P = .050). These preliminary findings highlight the potential for increased risks after even a short delay in receiving a methadone dose.

Nociceptive Flexion Reflex Threshold is No Suitable Marker for Diagnosing Opioid-Induced Hyperalgesia.

Opioid induced hyperalgesia (OIH) describes a state of altered pain sensation due to opioid exposure. It often occurs among persons with opioid use disorder receiving substitution therapy. The purpose of this study was to find out, whether OIH diagnosis could be facilitated by an objective pain indicating marker: the Nociceptive Flexion Reflex (NFR). Forty persons with opioid use disorder, 20 of them maintained on methadone and 20 treated with buprenorphine, as well as a control group of 20 opioid-free subjects, were examined. It was aimed to find out whether and in which way these opioid agonists alter reflex threshold (NFR-T). A cold-pressor test was performed to investigate the prevalence of OIH. Furthermore, electrical stimulation and electromyography analyzation were used for NFR-T measurement. Subjective pain ratings were evaluated with a numeric rating scale. Significantly increased sensitivity to cold pressor pain was found in both maintenance groups when compared to their opioid-free counterparts (p < 0.001). Neither methadone nor buprenorphine showed any effect on NFR-T. This might be explained by the reflex approaching at the wrong location in the central nervous system. Consequently, NFR-T is not a suitable marker for diagnosing OIH. Although methadone and buprenorphine have been proven to cause OIH, no effect on NFR-T was observed. A statistically significant effect could have been observed with a larger number of participants. Further research, with special focus on patients' adjuvant medication, should be conducted in the future, to facilitate diagnosis of OIH and provide appropriate pain management for maintenance patients.

Capillary electrophoresis using triple layer modified capillary facilitating salivary ion analyses: Application to search for potential stress markers induced by cold pressure test

In this study, we introduce a novel approach for the analysis of salivary ions using capillary electrophoresis (CE) with a triple-layer coated capillary. The capillary is sequentially coated with cationic silylating reagents, poly(vinylsulfonate), and polybrene to form a custom designed surface that effectively inhibits adsorption of protein matrix on the capillary inner wall and allows for reproducible ion analysis. For the CE with capacitively coupled contactless conductivity detection, we used suitable background electrolytes (BGEs) for salivary ion analysis. Anions were separated using a mixture of 2-(N-morpholino)ethanesulfonic acid and l-arginine, and cations were separated using that with 18-crown-6. This setup enabled rapid separation, within 4 min, together with sensitive detection. We quantified nine common anions and five cations typically found in saliva samples using this CE method, both before and after a cold pressure test (CPT, a standard stress test). The CE system demonstrated consistent ion separation across 30 consecutive measurements without requiring capillary replacement. Notably, the salivary ion balance remained predominantly anion-rich, regardless of the CPT. Cold water exposure induced greater variation in the total anion concentration than in the total cation concentration. Further analysis using multiple regression analysis revealed strong relationships between nitrate and nitrite, formate and phosphate, and potassium and nitrate, before and after the CPT. Notably, potassium and nitrate ions exhibited variations in response to stress. These results provided a method for assessing salivary ion composition and insights into the potential of salivary ions as biomarkers for stress.

Resilience of navigation strategy and efficiency to the impact of acute stress

ABSTRACT Increased cortisol may differentially impact navigation strategies. Three within-subjects experiments investigated how the Trier Social Stress Test (TSST), the Cold Pressor Test (CPT), and a prolonged bout of physical exercise (PE), all known to increase cortisol, affect navigation strategy and efficiency. Participants learned an environment, were stressed, and then navigated. Cortisol was higher in all stress sessions relative to a no-stress control session. TSST and CPT did not affect strategy or efficiency, while PE increased shortcut use. Results suggest navigation strategies are resilient to cortisol-based stress however questions remain as to how strategy shifts occur.

Cerebral sympatholysis: experiments on in vivo cerebrovascular regulation and ex vivo cerebral vasomotor control.

Whether cerebral sympathetic-mediated vasomotor control can be modulated by local brain activity remains unknown. This study tested the hypothesis that the application or removal of a cognitive task during a cold pressor test (CPT) would attenuate and restore decreases in cerebrovascular conductance (CVC), respectively. Middle cerebral artery blood velocity (transcranial Doppler) and mean arterial pressure (finger photoplethysmography) were examined in healthy adults (n = 16; 8 females and 8 males) who completed a control CPT, followed by a CPT coupled with a cognitive task administered either 1) 30 s after the onset of the CPT and for the duration of the CPT or 2) at the onset of the CPT and terminated 30 s before the end of the CPT (condition order was counterbalanced). The major finding was that the CPT decreased the index of CVC, and such decreases were abolished when a cognitive task was completed concurrently and restored when the cognitive task was removed. As a secondary experiment, vasomotor interactions between sympathetic transduction pathways (α1-adrenergic and Y1-peptidergic) and compounds implicated in cerebral blood flow control [adenosine, and adenosine triphosphate (ATP)] were explored in isolated porcine cerebral arteries (wire myography). The data reveal α1-receptor agonism potentiated vasorelaxation modestly in response to adenosine, and preexposure to ATP attenuated contractile responses to α1-agonism. Overall, the data suggest a cognitive task attenuates decreases in CVC during sympathoexcitation, possibly related to an interaction between purinergic and α1-adrenergic signaling pathways.NEW & NOTEWORTHY The present study demonstrates that the cerebrovascular conductance index decreases during sympathoexcitation and this response can be positively and negatively modulated by the application or withdrawal of a nonexercise cognitive task. Furthermore, isolated vessel experiments reveal that cerebral α1-adrenergic agonism potentiates adenosine-mediated vasorelaxation and ATP attenuates α1-adrenergic-mediated vasocontraction.

Sympathetic Neural Control at Rest and During the Cold Pressor Test in Patients With Heart Failure With Preserved Ejection Fraction.

We tested the hypothesis that patients with heart failure with preserved ejection fraction (HFpEF) would have greater muscle sympathetic nerve activity (MSNA) at rest and sympathetic reactivity during a cold pressor test compared with non-heart failure controls. Further, given the importance of the baroreflex modulation of MSNA in the control of blood pressure (BP), we hypothesized that patients with HFpEF would exhibit a reduced sympathetic baroreflex sensitivity. Twenty-eight patients with HFpEF and 44 matched controls (mean±SD: 71±8 versus 70±7 years; 9 men/19 women versus 16 men/28 women) were studied. BP, heart rate, and MSNA (microneurography) were measured during 6 to 10 minutes of supine rest and the 2-minute cold pressor test. Spontaneous sympathetic baroreflex sensitivity was assessed during supine rest. Patients with HFpEF had higher resting MSNA burst frequency (39±14 versus 31±12 bursts/min; P=0.020) and lower sympathetic baroreflex sensitivity (-2.83±0.76 versus -3.57±1.19 bursts/100 heartbeats/mm Hg; P=0.019) than controls, but burst incidence was not different between groups (56±19 versus 50±20 bursts/100 heartbeats; P=0.179). During the cold pressor test, increases in MSNA indices did not differ between groups (P=0.135-0.998), but patients had a smaller increase in diastolic BP (Δ4±6 versus Δ14±11 mm Hg; P<0.001) compared with controls. Despite augmented resting MSNA burst frequency, burst incidence was not significantly different between groups, and sympathetic baroreflex sensitivity was reduced in patients with HFpEF. Furthermore, patients had preserved sympathetic reactivity but attenuated diastolic BP responses during the cold pressor test. These data suggest that, during physiological stress, sympathetic reactivity is intact, but the peripheral pathway for sympathetic vasoconstriction may be impaired in HFpEF.

Cardiovascular reactivity to acute psychological stress is associated with generalized self-efficacy and self-efficacy outcomes during adventure challenges.

Outdoor adventure challenges are commonly used to enhance self-efficacy, but the physiological mechanisms involved remain unexplored. Additionally, while studies have documented the influence of self-efficacy on stress management, general self-efficacy has yet to be fully understood in the context of cardiovascular stress reactivity (CVR). This study investigated the influence of self-efficacy beliefs on CVR during acute psychological stress tasks. Additionally, it explored whether CVR serves as a novel mechanism underlying the outcomes of outdoor adventure challenges. As part of a wider randomized controlled trial, participants (n = 55) were invited to complete a laboratory session to assess CVR to an active (paced auditory serial addition test (PASAT)) and a passive (cold pressor test (CPT)) stress task. Randomized participants (n = 33) to the experimental condition also engaged in a high ropes challenge course after the laboratory session. It was found that greater self-reported self-efficacy was associated with larger CVR during the CPT and positively associated with perceived engagement and performance during the PASAT. Secondly, participants reporting positive change in self-efficacy post-intervention were associated with greater CVR and greater CVR was associated with higher ratings of intervention engagement and perceived challenge. This study provides preliminary evidence suggesting that greater efficacy beliefs may heighten CVR to passive acute psychological stressors. Habitual stress reactivity may represent a novel mechanism involved in outdoor and adventure-based interventions. Future research should continue to explore the impact of psychological variables on stress physiology and examine CVR as a potential mechanism in adventure experiences.

Cardiac Autonomic Reactivity Tests in Type A and Type B Personalities.

A considerable link between personality types and cardiovascular diseases (CVDs) has been seen. Autonomic responses in both type A and type B personality individuals were found to be influenced by their personality traits. The study suggests further research on cardiac autonomic functions in larger sample sizes and the use of non-invasive screening techniques like cardiovascular reflex tests to stratify participants' risk of future illness. This study aimed to assess autonomic stress reactivity tests in type A and type B personalities using cardiovascular reflex tests. This study was conducted at the Department of Physiology, Vardhman Mahavir Medical College and Safdarjung Hospital, New Delhi. The Hunter-Wolf Personality Questionnaire Scale was used to identify 60 adults, 30 of whom were classified to have type A personality and 30 have type B personality, from the psychiatry department. Autonomic function tests, such as the handgrip tests, cold pressor test, deep breathing test (DBT), lying-to-standing test (LST), and Valsalva maneuver, were performed and recorded for each subject. IBM SPSS Statistics for Windows, version 21 (released 2012; IBM Corp., Armonk, New York, United States) was used for the compilation and analysis of data. The E:I (expiration-to-inspiration) ratio and delta heart rate of the type A personality patients both significantly decreased (p = 0.000*) as compared to the type B personality patients (1.18 ± 0.03 versus 1.25 ± 0.77 and 1.18 ± 0.03 versus 1.25 ± 0.77). The Valsalva ratio of the type A personality patients decreased (1.38 ± 0.10) as compared to the type B personality patients (1.48 ± 0.18), which was statistically significant (p = 0.001*). The 30:15 ratio in the type A personality patients was significantly decreased (p = 0.03*) compared to the type B personality patients (1.12 ± 0.05 versus 1.15 ± 0.10). The handgrip test and cold pressor test results were statistically insignificant. Compared to the type B personality patients, which exhibited an increase in both parasympathetic and sympathetic reactivity, the type A personality patients exhibited a reduction in resting cardiovascular parameters and resting autonomic tone. Consequently, in order to stratify the participants' risk of future illness, we recommend employing non-invasive procedures, such as cardiovascular reflex tests, as a screening technique.