Reduction in Pain Sensitivity from Pharmacological Elevation of Blood Pressure in Persons with Chronically Low Blood Pressure

Recent studies have revealed evidence for increased pain sensitivity in individuals with chronically low blood pressure. The present trial explored whether pain sensitivity can be reduced by pharmacological elevation of blood pressure. Effects of the sympathomimetic midodrine on threshold and tolerance to heat pain were examined in 52 hypotensive persons (mean blood pressure 96/61 mmHg) based on a randomized, placebo-controlled, double-blind design. Heat stimuli were applied to the forearm via a contact thermode. Confounding of drug effects on pain perception with changes in skin temperature, temperature sensitivity, and mood were statistically controlled for. Compared to placebo, higher pain threshold and tolerance, increased blood pressure, as well as reduced heart rate were observed under the sympathomimetic condition. Increases in systolic blood pressure between points of measurement correlated positively with increases in pain threshold and tolerance, and decreases in heart rate were associated with increases in pain threshold. The findings underline the causal role of hypotension in the augmented pain sensitivity related to this condition. Pain reduction as a function of heart rate decrease suggests involvement of a baroreceptor-related mechanism in the pain attrition. The increased proneness of persons with chronic hypotension toward clinical pain is discussed.

Download Full-text

Caffeine and Placebo Expectation

Journal of Psychophysiology ◽

10.1027/0269-8803.21.2.91 ◽

2007 ◽

Vol 21 (2) ◽

pp. 91-99 ◽

Cited By ~ 8

Author(s):

Yunfeng Sun ◽

Yinling Zhang ◽

Ning He ◽

Xufeng Liu ◽

Danmin Miao

Keyword(s):

Blood Pressure ◽

Heart Rate ◽

Sleep Deprivation ◽

Cognitive Performance ◽

Cognitive Functions ◽

Cardiovascular Regulation ◽

Double Blind ◽

Positive Effects ◽

Pressure Tests ◽

Healthy Males

Abstract. Caffeine placebo expectation seems to improve vigilance and cognitive performance. This study investigated the effect of caffeine and placebo expectation on vigilance and cognitive performance during 28 h sleep deprivation. Ten healthy males volunteered to take part in the double-blind, cross-over study, which required participants to complete five treatment periods of 28 h separated by 1-week wash-out intervals. The treatments were no substance (Control); caffeine 200 mg at 00:00 (C200); placebo 200 mg at 00:00 (P200); twice caffeine 200 mg at 00:00 and 04:00 (C200-C200); caffeine 200 mg at 00:00 and placebo 200 mg at 04:00 (C200-P200). Participants were told that all capsules were caffeine and given information about the effects of caffeine to increase expectation. Vigilance was assessed by a three-letter cancellation test, cognitive functions by the continuous addition test and Stroop test, and cardiovascular regulation by heart rate and blood pressure. Tests were performed bihourly from 00:00 to 10:00 of the second day. Results indicated that C200-P200 and C200-C200 were more alert (p < .05) than Control and P200. Their cognitive functions were higher (p < .05) than Control and P200. Also, C200-P200 scored higher than C200 in the letter cancellation task (p < .05). No test showed any significant differences between C200-P200 and C200-C200. The results demonstrated that the combination of caffeine 200 mg and placebo 200 mg expectation exerted prolonged positive effects on vigilance and cognitive performance.

Download Full-text

The Effects of a Caffeine Placebo and Experimenter Expectation on Blood Pressure, Heart Rate, Well-Being, and Cognitive Performance

European Psychologist ◽

10.1027//1016-9040.6.1.15 ◽

2001 ◽

Vol 6 (1) ◽

pp. 15-25 ◽

Cited By ~ 18

Author(s):

Harald Walach ◽

Stefan Schmidt ◽

Yvonne-Michelle Bihr ◽

Susanne Wiesch

Keyword(s):

Blood Pressure ◽

Heart Rate ◽

Cognitive Task ◽

Well Being ◽

Control Group ◽

Double Blind ◽

Main Effect ◽

The Difference ◽

Being There ◽

To Receive

We studied the effect of experimenter expectations and different instructions in a balanced placebo design. 157 subjects were randomized into a 2 × 4 factorial design. Two experimenters were led to expect placebos either to produce physiological effects or not (pro- vs. antiplacebo). All subjects except a control group received a caffeine placebo. They were either made to expect coffee, no coffee, or were in a double-blind condition. Dependent measures were blood pressure, heart rate, well-being, and a cognitive task. There was one main effect on the instruction factor (p = 0.03) with the group “told no caffeine” reporting significantly better well-being. There was one main effect on the experimenter factor with subjects instructed by experimenter “proplacebo” having higher systolic blood pressure (p = 0.008). There was one interaction with subjects instructed by experimenter “proplacebo” to receive coffee doing worse in the cognitive task than the rest. Subjects instructed by experimenter “antiplacebo” were significantly less likely to believe the experimental instruction, and that mostly if they had been instructed to receive coffee. Contrary to the literature we could not show an effect of instruction, but there was an effect of experimenters. It is likely, however, that these experimenter effects were not due to experimental manipulations, but to the difference in personalities.

Download Full-text

Can Residential Greenspace Exposure Improve Pain Experience? A Comparison between Physical Visit and Image Viewing

Healthcare ◽

10.3390/healthcare9070918 ◽

2021 ◽

Vol 9 (7) ◽

pp. 918

Author(s):

Hansen Li ◽

Xing Zhang ◽

Shilin Bi ◽

Yang Cao ◽

Guodong Zhang

Keyword(s):

Heart Rate ◽

State Anxiety ◽

Pain Threshold ◽

Pain Perception ◽

The State ◽

Subjective Stress ◽

Pain Experience ◽

Scenic Beauty ◽

Significant Difference ◽

Pain Stimuli

Reducing the burden of pain via greenspace exposure is a rising research topic. However, insufficient evidence has been found in relation to the environmental effect itself. Residential greenspace, as a convenient but limited natural environment for urban dwellers, has benefits and services yet to be discovered. Therefore, the current study recruited 24 young adults to evaluate the effects of physical visit to, or image viewing of, residential greenspace on pain perception and related psychophysiological outcomes, via simulated pain. Pain threshold and tolerance were recorded via the level of pain stimuli, and pain intensity was evaluated using the Visual Analog Scale (VAS). The state scale of the State–Trait Anxiety Inventory (STAI-S) and two adjective pairs were employed to measure the state anxiety and subjective stress, respectively. Meanwhile, heart rate (HR), heart rate variability (HRV), and blood pressure (BP) were measured to investigate physiological responses. Besides, Scenic Beauty Estimation (SBE) was also employed to assess participants’ preference regarding the experimental environments. The results revealed that visiting the greenspace significantly increased the pain threshold and tolerance, while no significant effect was observed for image viewing. On the other hand, no significant difference was observed in pain-related psychophysiological indices between the experimental settings, but significantly negative associations were found between the scores of SBE and subjective stress and state anxiety. In conclusion, the current study brings experimental evidence of improving pain experience via residential greenspace exposure, while the related psychophysiological benefits require further investigation.

Download Full-text

Swearing as a response to pain: Assessing hypoalgesic effects of novel “swear” words

10.31234/osf.io/cdvyf ◽

2019 ◽

Author(s):

Richard Stephens ◽

Olly May Robertson

Keyword(s):

Heart Rate ◽

Repeated Measures ◽

Neutral Word ◽

Pain Threshold ◽

Pain Perception ◽

Cold Pressor ◽

Pain Tolerance ◽

Mediation Effects ◽

Independent Variable ◽

Cold Pressor Pain

Background: This pre-registered study extends previous findings that swearing alleviates pain tolerance by assessing the effects of a conventional swear word (“fuck”) and two new “swear” words, “fouch” and “twizpipe”.Method: A mixed sex group of participants (N = 92) completed a repeated measures experimental design augmented by mediation analysis. The independent variable was Word with the levels, “fuck” v. “fouch” v. “twizpipe” v. a neutral word. The dependent variables were emotion rating, humour rating, distraction rating, cold pressor pain threshold, cold pressor pain tolerance, pain perception score and change from resting heart rate. Possible mediation effects were assessed for emotion, humour and distraction ratings. Results: For conventional swearing (“fuck”), confirmatory analyses found a 32% increase in pain threshold and a 33% increase in pain tolerance, accompanied by increased ratings for emotion, humour and distraction, relative to the neutral word condition. The new “swear” words, “fouch” and “twizpipe” were rated higher than the neutral word for emotion and humour although these words did not affect pain threshold or tolerance. Changes in heart rate, pain perception and were absent, as were mediation effects.Conclusions: Our data replicate previous findings that repeating a swear word at a steady pace and volume benefits pain tolerance, extending this finding to pain threshold. Our data cannot explain how such effects are manifest, although distraction appears to be of little importance, and emotion is worthy of future study. The new “swear” words did not alleviate pain even though participants rated them as emotion evoking and humorous.

Download Full-text

Gender Differences in Response to Experimental Pain among Medical Students from a Western State of India

International Journal of Medical Students ◽

10.5195/ijms.2014.69 ◽

2014 ◽

Vol 2 (1) ◽

pp. 13-17

Author(s):

Pratik Akhani ◽

Samir Mendpara ◽

Bhupendra Palan

Keyword(s):

Blood Pressure ◽

Gender Differences ◽

Medical Students ◽

Pain Sensitivity ◽

Pain Threshold ◽

Experimental Pain ◽

Pain Tolerance ◽

Medical Attention ◽

Pain Rating ◽

Western State

Background: Pain is one of the most common reasons for patients to seek medical attention and it causes considerable human suffering. Pain is a complex perception that differs enormously among individual patients. Gender plays an important role in how pain is experienced, coped with and treated. Even young healthy individuals often differ in how they perceive and cope with pain. This study was done to investigate gender differences in response to experimental pain among medical students from a western state in India. Methods: A total of 150 medical students (86 males and 64 females) participated in this interventional study. The Cold Pressor Test was used to exert experimental pain. To study the response, cardiovascular measures (radial pulse, systolic blood pressure and diastolic blood pressure) and pain sensitivity parameters (pain threshold, pain tolerance and pain rating) were assessed. Results: No significant difference was found in cardiovascular response to experimental pain between both the genders (p>0.05). Pain threshold and pain tolerance were found to be significantly higher in males whereas pain rating was found to be significantly higher in females (p<0.01). Pulse reactivity showed a negative relationship with pain threshold and pain tolerance whereas a positive relationship with pain rating, however no statistically significant relation was found between these measures. Conclusion: Females display greater pain sensitivity than males. Different pain perception might account for gender difference in pulse reactivity.

Download Full-text

Music for pain in healthy neonates

Paediatrica Indonesiana ◽

10.14238/pi61.2.2021.69-73 ◽

2021 ◽

Vol 61 (2) ◽

pp. 69-73

Author(s):

Nessie Amelia Ramli ◽

Afifa Ramadanti ◽

Indrayady Indrayady ◽

Yuli Doris Memy

Keyword(s):

Heart Rate ◽

Pain Perception ◽

Periventricular Leukomalacia ◽

Pain Scale ◽

Injection Pain ◽

Medical Procedure ◽

Music Intervention ◽

Older Children ◽

Double Blind ◽

Infant Pain

Background The neonatal pain threshold is 30-50% lower than in adults and older children because of immature pain inhibition function in nervous centers. Acute pain in neonates results in behavioral, physiological, and cerebral blood flow changes that may lead to intraventricular bleeding and periventricular leukomalacia. Music is believed to reduce pain perception as it distracts, influencing the parasympathetic and sympathetic nervous system by decreasing pulse rate, blood pressure, and breathing, hence, promoting a relaxed state. Objective To evaluate effects of music intervention on physiological parameters and pain perception in healthy newborns undergoing a painful medical procedure (immunization injection). Methods This was a double-blind, randomized control trial study. A recorded instrumental lullaby “Nina Bobo” was given for 5 minutes to the music group and no music for control, prior injection of Hepatitis B 0. The evaluation of heart rate and SpO2 were performed at baseline, 30 seconds, and 5 minutes after injection. Pain perception were measured by Neonatal Infant Pain Scale (NIPS) at 30 seconds and 5 minutes after injection. Results Total of 51 subjects were enrolled. There were no difference of SpO2 and NIPS between both music and control groups. Music improved heart rate after 30 seconds and 5 minutes after injection, median 126 (range 55-149) bpm from median 136 (range 78-154) bpm, and even lower than baseline [mean 128.9 (SD 12.5) bpm; P=0.019]. The control showed no improvement of heart rate mean 124,34 (SD 18,45) from 124,73 (SD 18,39); P=0.875There were no significant differences between the 2 groups. Conclusion Music is not effective in improving oxygen saturation, heart rate, and is not effective in reducing the degree of pain.

Download Full-text

Effects of Preoperative Intravenous Clonidine in Patients Undergoing Cataract Surgery: A Double-Blind, Randomized Trial

Journal of Ophthalmology ◽

10.1155/2014/346549 ◽

2014 ◽

Vol 2014 ◽

pp. 1-5 ◽

Cited By ~ 1

Author(s):

Ana Ellen Queiroz Santiago ◽

Adriana Machado Issy ◽

Rioko Kimiko Sakata

Keyword(s):

Blood Pressure ◽

Heart Rate ◽

Intraocular Pressure ◽

Myocardial Ischemia ◽

Cataract Surgery ◽

The Other ◽

Intraocular Lens Implantation ◽

Double Blind ◽

Lens Implantation ◽

Lidocaine Gel

Objectives. The aim of this study was to assess the effects of clonidine on intraoperative analgesia, sedation, intraocular and blood pressure, arrhythmia, and ischemia.Methods. Forty patients undergoing cataract surgery were allocated into two groups. They were monitored with Holter machine, the pupil was dilated, and 30 minutes later, 20 patients received clonidine (4 µg/kg), while the other 20 patients were given a 0.9% saline intravenously. Twenty minutes later, 2% lidocaine gel was applied. There were assessed intraoperative analgesia, intraocular pressure, blood pressure, heart rate, and the occurrence of arrhythmias and myocardial ischemia.Results. Pain intensity was lower in G1 during the phacoemulsification, irrigation, aspiration, and intraocular lens implantation. The HR and BP were lower with clonidine. The IOP was lower with clonidine after 15 minutes and at the end of the surgery. Sedation was higher with clonidine. The incidence of arrhythmia was lower at the end of surgery with clonidine. The incidence of myocardial ischemia did not differ between the groups.Conclusions. Clonidine (4 µg/kg) before a phacoemulsification reduced the intensity of pain during cataract surgery. It also induced sedation, reduction of BP, HR, and incidence of arrhythmia at the end of the surgery, and did not alter myocardial ischemia. This trial is registered with Clinicaltrials.govNCT01677351.

Download Full-text

A Comparison of Atenolol and Long-Acting Trimazosin in Mild to Moderate Essential Hypertension

Scottish Medical Journal ◽

10.1177/003693308503000207 ◽

1985 ◽

Vol 30 (2) ◽

pp. 106-110 ◽

Cited By ~ 2

Author(s):

D. J. Webb ◽

M. J. Hutcheson ◽

M. P. Robertson ◽

G. D. Murray ◽

A. R. Lorimer ◽

...

Keyword(s):

Blood Pressure ◽

Heart Rate ◽

Moderate Hypertension ◽

Diastolic Pressure ◽

Substantial Reduction ◽

Density Lipoprotein ◽

Double Blind ◽

Randomised Study ◽

Lipoprotein Concentration ◽

Long Acting

In a 12-week double-blind randomised study the efficacy of atenolol and a new longer-acting formulation of trimazosin were compared when given once daily in patients with mild to moderate hypertension. Two parallel groups, each consisting of 18 patients, were studied. At randomisation the two groups were well matched for age and sex distribution. They were also well matched for blood pressure, pulse rate and body weight; these latter measurements were recorded at regular intervals during the 12 weeks of study. Atenolol produced substantial reduction in both systolic and diastolic blood pressure, and in heart rate, during 12 weeks of treatment. This therapeutic effect was maintained until the next dose after 24 hours. Trimazosin, by comparison, failed to reduce either systolic or diastolic pressure, or to alter heart rate. Side effects were minor with both agents and compliance with treatment was good. Atenolol caused significant elevation of plasma concentration of triglyceride, with reduction in high density lipoprotein concentration when compared with trimazosin. In conclusion, atenolol was confirmed as an effective agent for the treatment of mild to moderate hypertension. By comparison trimazosin in the longer-acting formulation was ineffective in this study. However, trimazosin may still find a place in treatment if used at higher dose.

Download Full-text

The effects of propranolol on heart rate variability and quantitative, mechanistic, pain profiling: a randomized placebo-controlled crossover study

Scandinavian Journal of Pain ◽

10.1515/sjpain-2018-0054 ◽

2018 ◽

Vol 18 (3) ◽

pp. 479-489 ◽

Cited By ~ 6

Author(s):

Kristian Kjær Petersen ◽

Hjalte Holm Andersen ◽

Masato Tsukamoto ◽

Lincoln Tracy ◽

Julian Koenig ◽

...

Keyword(s):

Blood Pressure ◽

Heart Rate ◽

Chronic Pain ◽

Pain Sensitivity ◽

Experimental Pain ◽

Central Pain ◽

Healthy Male ◽

Pain Pathways ◽

Β Blocker ◽

Chronic Pain Conditions

AbstractBackground and aimsThe autonomic nervous system (ANS) is capable of modulating pain. Aberrations in heart rate variability (HRV), reflective of ANS activity, are associated with experimental pain sensitivity, chronic pain, and more recently, pain modulatory mechanisms but the underlying mechanisms are still unclear. HRV is lowered during experimental pain as well as in chronic pain conditions and HRV can be increased by propranolol, which is a non-selective β-blocker. Sensitization of central pain pathways have been observed in several chronic pain conditions and human mechanistic pain biomarkers for these central pain pathways include temporal summation of pain (TSP) and conditioned pain modulation (CPM). The current study aimed to investigate the effect of the β-blocker propranolol, and subsequently assessing the response to standardized, quantitative, mechanistic pain biomarkers.MethodsIn this placebo-controlled, double-blinded, randomized crossover study, 25 healthy male volunteers (mean age 25.6 years) were randomized to receive 40 mg propranolol and 40 mg placebo. Heart rate, blood pressure, and HRV were assessed before and during experimental pain tests. Cuff pressure pain stimulation was used for assessment of pain detection (cPDTs) and pain tolerance (cPTTs) thresholds, TSP, and CPM. Offset analgesia (OA) was assessed using heat stimulation.ResultsPropranolol significantly reduced heart rate (p<0.001), blood pressure (p<0.02) and increased HRV (p<0.01) compared with placebo. No significant differences were found comparing cPDT (p>0.70), cPTT (p>0.93), TSP (p>0.70), OA-effect (p>0.87) or CPM (p>0.65) between propranolol and placebo.ConclusionsThe current study demonstrated that propranolol increased HRV, but did not affect pressure pain sensitivity or any pain facilitatory or modulatory outcomes.ImplicationsAnalgesic effects of propranolol have been reported in clinical pain populations and the results from the current study could indicate that increased HRV from propranolol is not associated with peripheral and central pain pathways in healthy male subjects.

Download Full-text

Effects of 12-Week Supplementation of a Polyherbal Formulation in Old Adults with Prehypertension/Hypertension: A Randomized, Double-Blind, Placebo-Controlled Trial

Evidence-based Complementary and Alternative Medicine ◽

10.1155/2019/7056872 ◽

2019 ◽

Vol 2019 ◽

pp. 1-15 ◽

Cited By ~ 2

Author(s):

Tian Shen ◽

Guoqiang Xing ◽

Jingfen Zhu ◽

Yong Cai ◽

Shuxian Zhang ◽

...

Keyword(s):

Blood Pressure ◽

Heart Rate ◽

Placebo Group ◽

Controlled Trial ◽

Adult Population ◽

Chest Tightness ◽

Double Blind ◽

Old Adults ◽

Severity Scores ◽

Rapid Heart Rate

Background. Uncontrolled blood pressure is the leading cause of mortality and disability due to associated cerebral and cardiovascular diseases and kidney failure. More than one-third of the old adult population have hypertension or prehypertension and many of their blood pressure are poorly controlled. Objective. We hypothesized that plant extracts-based antioxidants may benefit those with prehypertension/hypertension. Method. One hundred age- and gender-matched healthy older adults were randomly assigned to receive HyperBalance capsules (n=50) or placebo (n=50) at Tang-Qiao Community Health Service Center, Shanghai. Blood pressure and severity scores of hypertension treatment-related symptoms (dizziness, headache, ringing/buzzing in ears, rapid heart rate, and chest tightness) were evaluated before and after the 12-week intervention. Results. Ninety-eight people completed the study, with 2 dropouts in the placebo group before the end of the study. Forty-one subjects (82%) of the HyperBalance group and 40 subjects (83.3%) of the placebo group had prehypertension (systolic blood pressures (SBP) between 130-139 and diastolic blood pressure (DBP) between 85-89mmHg), and 9 subjects (18%) in the HyperBalance group and 8 subjects (16.7%) in the placebo group had hypertension (≥140/90mmHg) before the intervention. HyperBalance significantly (P<0.01) reduced SBP from 136.18±4.38 to 124.14±3.96 mmHg and reduced DBP from 82.45±2.91 to 80.24±2.41mmHg, respectively, and reversed all 9 hypertension people to normotension or prehypertension state, whereas the placebo moderately reduced SBP from 135.79±4.22 to 132.35±4.656mmHg and reduced DBP from 82.90±3.07 to 82.27±3.01mmHg. All symptom severity scores became significantly lower in the HyperBalance group than in the placebo group after HyperBalance intervention: dizziness (0.82±0.44; vs 2.02±0.64, P<0.01); headache (0.46±0.50; vs 1.81±0.61, P<0.01); ringing/buzzing in ears (0.44±0.50; vs 1.04±0.29, P<0.01); and rapid heart rate and chest tightness (0.30±0.46; vs 0.92±0.28, P<0.01). Conclusion. Polyherbal supplementation such as HyperBalance could benefit old adults with prehypertension/hypertension and improve treatment-related symptoms. Further studies are needed to validate the current findings.

Download Full-text