|Year : 2021 | Volume
| Issue : 2 | Page : 89-92
Gender differences in pain perception during experimentally induced pain: An observational study
Anoop Joy1, Muhammed Rashid2, Ludhiya Baby1, Jerin Mathew3
1 Department of Physiotherapy, Laxmi College of Physiotherapy, Mangalore, India
2 Department of Rehabilitation Research, JSS College of Physiotherapy, Dunedin, New Zealand
3 Centre for Health, Activity, and Rehabilitation Research (CHARR), University of Otago, Dunedin, New Zealand
|Date of Submission||24-Oct-2021|
|Date of Decision||17-Dec-2021|
|Date of Acceptance||17-Dec-2021|
|Date of Web Publication||15-Feb-2022|
Mr. Muhammed Rashid
JSS College of Physiotherapy, JSS Hospital Campus, MG Road, Agrahara, Mysuru - 570 004, Karnataka
Source of Support: None, Conflict of Interest: None
BACKGROUND: There are multiple biopsychosocial mechanisms which influence the pain responses between genders. Even though there are enough literature that describe the perception of pain, no consensus has made which gender is more sensitive or tolerance to pain. The study evaluates the difference in pain threshold (PThr), pain tolerance (PTol), and intensity of pain between individuals of both genders and to find which gender is more sensitive to pain.
METHODOLOGY: The study was conducted on 106 participants (53 males and 53 females) with age 18–25 years. The participants had undergone cold-induced test (CIT) and tourniquet pressure test (TPT). The PThr, PTol, and pain intensity were recorded and the data were analyzed by Mann–Whitney test.
RESULTS: The results also found a significant difference in PThr between both genders (P = 0.001). However, males have taken longer time to perceive PThr in both TPT and CIT as compared to females. In the case of PTol, females had a less tolerable level of both TP and CIT as compared to males.
CONCLUSION: The differences in the pain perception between genders can vary greatly because of different factors, thus we can say that males have higher PThr and PTol than females.
Keywords: And tourniquet, cold, experimentally induced pain perception, pain intensity, pain threshold, pain tolerance
|How to cite this article:|
Joy A, Rashid M, Baby L, Mathew J. Gender differences in pain perception during experimentally induced pain: An observational study. Physiother - J Indian Assoc Physiother 2021;15:89-92
|How to cite this URL:|
Joy A, Rashid M, Baby L, Mathew J. Gender differences in pain perception during experimentally induced pain: An observational study. Physiother - J Indian Assoc Physiother [serial online] 2021 [cited 2022 May 21];15:89-92. Available from: https://www.pjiap.org/text.asp?2021/15/2/89/337722
| Introduction|| |
Pain is a multifactorial phenomenon influenced by tissue injury and emotional, sociocultural, and environmental aspects and is conceptualized as “an unpleasant sensory and emotional experience that is described in terms of actual or potential tissue injuries.” Sensation of pain is considered as a protective mechanism of the body against tissue damage, acting as a psychological adjunct to a protective reflex that causes the affected tissue to diverge from harmful and/or noxious stimuli. There are multiple bio-psycho-social mechanism including sex hormones, endogenous opioid function, genetic factors, pain coping and catastrophizing, which contribute in the influence pain responses between genders.,
Differences in responses to experimental pain in both genders have been investigated by using a wide variety of stimuli (mechanical, electrical, thermal, ischemic, and chemical). Pain responses such as pain threshold (PThr), pain tolerance (PTol), and pain intensity have been evaluated by different measures including time and intensity. PThr is defined as the level of stimulus at which the participant first recognizes pain or discomfort, whereas PTol is a greater level of stimulus at which the participant requests for the stimulus to stop or be discontinued and pain intensity is the subjective measure of magnitude of the experienced pain. Evidence from literature shows that disparities in gender can influence the perception of pain to different stimuli at different anatomical locations.,
According to the existing literature, disparities in gender can influence in perception of pain to different stimuli at different areas. Even though there are enough literature that describe the perception of pain, no consensus has made which gender is more sensitive or tolerance to pain., Because of the disparities made between genders, no literature says that which gender is more sensitive or tolerance to pain, so this study evaluates the difference in PThr, PTol, and intensity of pain between individuals of both genders and to find which gender is more sensitive to pain. The objective of this study is to evaluate the differences in PThr, PTol, and perception of pain intensity between the genders and also to document which stimuli have more pain perception in both genders.
| Methodology|| |
Methodological descriptions of this observational exploratory study followed the “Strengthening the Reporting of Observational Studies in Epidemiology” checklist. The minimum sample size was obtained as 106 using G* power 3.0.10 software (Gpower, Aichach, Germany) considering a moderate effect size of 0.5, α error = 0.05, and power (1 − β) = 0.8 for two groups and three repetitions.
Fifty-three male and fifty-three female aged 17–25 were recruited for the study by convenience sampling method. Individuals with radiating pain and sensory deficits around upper limb are excluded from the study. Furthermore, individuals with any cardiovascular, neuromuscular, or peripheral vascular disorders or with recent upper-limb trauma, hypertension, and hypotension and individuals under analgesics of any family or medications other than over the drug category are excluded from the study. The study protocol was reviewed and approved by the Institutional Research Committee. Eligible participants were explained about the aims and procedures of the study, and informed consent was obtained. A research administrator not involved in the study performed a concealed randomized allocation of date and time for each participant. Materials for the study were arranged 1 day prior to the test, and the consent form was obtained from the participants prior to the commencement of the test. On the test day, participants were accommodated in a room with comfortable posture to acclimatized for the study and free of any situation that could cause distraction or procedure artifacts.
The test procedure was divided into two sessions as follows:
- Session 1 – Tourniquet pressure test (TPT)
- Session 2 – Cold-induced test (CIT).
The test was performed with five participants daily in the evening, as it was the convenient time for the participants. After each session, a rest period of 8 h was given to subset the painful sensation. A single test was performed on participants a day to avoid the accommodation of pain and associated tissue response.
In CIT [Figure 1], each participant immersed his/her nondominant hand up to the wrist in cold water (0°C–2°C) kept in a beaker (BFC Borosilicate beaker) and the temperature is maintained throughout the procedure, by adding ice to the beaker, monitored using a digital thermometer (LCD portable digital multistem thermometer HT-9263). Participants were instructed not to move their immersed hand during the task until the maximum subjective intensity, forcing them to withdraw their hand when they feel pain. PThr was documented when the participant reported the first sign of painful sensation, and PTol was documented when the participant reported that he/she is not able to tolerate pain furthermore, which forced the participant to withdraw their hand from cold water, and the PThr and PTol are measured by using a digital stopwatch (Casio S023). The Visual Analog Scale (VAS) was administered to record subjective pain intensity at PThr and PTol level.
A modified tourniquet test [Figure 2] procedure was administered next day for Session 2. Participants were instructed to place their nondominant hand on a table with comfortable posture which is elevated above their heart level to reduce blood flow to the hand. Sphygmomanometer cuffs fastened to the participants arm after 30 s of rest and inflated to 200 mmHg. Participants were instructed to discontinue the procedure at any time if they experience dizziness or an abnormal response to the procedure. PThr, PTol, and pain intensity were recorded the same as Stage 1.
Demographic data were summarized descriptively. Comparison between gender and tests were performed using Mann–Whitney U-test using “SPSS software (Statistical Package for the Social Sciences) 22.0 version (IBM Corp., Armonk, Newyork, USA).
| Results|| |
The demographic characteristics of participants are given in [Table 1].
Since the data were nonnormally distributed, nonparametric tests were performed for comparison. The results of the study were generated using Mann–Whitney U-test, and it was found significant differences in both CIT and TPT pain intensities (P = 0.001) between genders [Table 2]. The results also found a significant difference in PThr between both genders (P = 0.001). However, males have taken longer time to perceive PThr in both TPT (median: 4 s) and CIT (median: 2 s) as compared to females (median TPT: 2 s and median CIT: 1 s). In the case of PTol, females had a less tolerable level of both TPT (median: 3 s) and CIT (median: 1 s) as compared to males (median TPT: 7 s and CIT: 2 s). The pain intensity level was more in females (median TPT and CIT: VAS 3) than males (median TPT and CIT: VAS 2). The results of the study are summarized in [Table 2].
| Discussion|| |
This study is designed to find out the gender differences in pain perception during experimentally induced pain for age group between 17 and 25 years using TPT and CIT. The outcome measure for the pain intensity of both tests was obtained using VAS. In this study, data of different parameters were collected and analyzed using Wilcoxon Mann–Whitney t-test (two groups) and results were generated with statistically significance at the level of 0.00. At the initial phase of the TPT, three participants were appeared with red rashes over the tourniquet applied area of the tested arm due to the mild degree of ischemia and subsided after 2 h. To overcome this issue, participants were instructed to wear full sleeve cloths on the test day to resolve the aforementioned ischemic problem. Out of 120 recruited participants, 14 were excluded from the study as they have presented with hypersensitivity to the cold, pressure, or due to the overanxiety which may potentially have an impact on the results of the study.
This study demonstrates a significant difference in pain perception between both genders, and males took longer time to perceive the pain sensation (threshold) as compared to females. It was found that PTol level in female is lesser than their male counter parts. This gender difference could be attributed to physiological, sociocultural, and psychological variables.
The differences in the pain perception between genders can vary greatly because of different factors such as psychological characteristics; different levels of anxiety, depression, or previous painful experiences; and physiologic mechanisms, including hormonal changes in menstrual cycle, baroreceptor activation, and opioid activity.
The physiological mechanisms play a fundamental role in sex-related differences in pain, and it reflects in the endogenous opioid system. Estradiol and progesterone's effects on pain sensitivity are relatively complex in both pro-nociceptive and anti-nociceptive effects on pain. Progesterone increases excitability of spinal neurons by altering the permeability of ion channels, thus it decreases PThr in females. The testosterone appears to be more anti-nociceptive and protective in nature having a masking effect on the perception of pain. Endorphins are the endogenous analgesic substances which causes activation of analgesic system of body. Males release more endorphin than females, thus increase in quantity of endorphin in the males greatly increases their PThr. Males are more motivated to support and repress pain expressions due to sociocultural and psychological influences of the male sexual role, while the female sexual role encourages pain expression and produces lower motivation to support pain. The differences in the sensation of pain between genders can vary greatly because of different factors which influence the results like psychological characteristics of each participant; different levels of anxiety, depression, or previous painful experiences of each participant can alter the reports of pain. The physiologic mechanisms, including baroreceptor activation and opioid activity, may underlie sex differences in pain perception, thus we can say that males have higher PThr and PTol than females.
This study has shown that a significant difference in pain perception between both genders in which males have longer time to perceive pain sensation (threshold) in both TPT and CIT as compared to females, and in the case of PTol, females have a less tolerable level than males in both TPT and CIT which is in line with other authors.,,,
Cold-induced pain was more sensitive in both genders as compared to tourniquet-induced pain; this must be due to the fact that the temperature difference is perceived by thermoreceptors located on the surface of the skin as well as free nerve endings. The cold receptors are linked to medium-diameter myelinated fibers in Group Aδ, although there are some fibers attached to small calibrated nonmyelinated fibers in Group C. Nerve fibers react differently to each stimulus. When the temperature is very low, close to 0°C, only cold-pain fibers are stimulated; it was reported that, when immersing a region in cold water, the first perceived sensation is the cold, replaced in by a deep sense of pain and discomfort, triggering sensations of pricking, stinging, and tingling.
Females exhibited lower PThr and PTol levels, which are less resistant to peripheral nerves injury induced by cold application. This study helps in designing the intensity and frequency of modalities based upon the sensitivity of pain in males and females which may provide an effective treatment response with minimal adverse effects such as peripheral nerve and vascular injuries.
| Conclusion|| |
This study concludes that there is a significant difference in pain perception between genders for both PThr and PTol. Males have taken longer time to perceive pain sensation (threshold) in both TPT and CIT as compared to females, and in the case of PTol, females have a less tolerable level as compared to males in both TPT and CIT. Cold-induced pain is more sensitive in both genders as compared to tourniquet induced pain. According to this study, differences in pain responses between genders should be considered, since the indiscriminate standardization of treatment dosage could lead to tissue injuries.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2]
[Table 1], [Table 2]