Exercise and Pain in Non-Hispanic Blacks and Whites

December 8, 2018 updated by: Brett Wong, Georgia State University

Effect of Exercise on Pain Responses in Non-Hispanic Blacks and Whites

Non-Hispanic Blacks tend to report higher levels of pain, experience pain more frequently, and be under-treated for pain compared to non-Hispanic Whites. Acute (single session) exercise is known to be effective at reducing pain but it is unknown what effect chronic exercise training has on pain responses. The broad goal of this study is to determine whether regular exercise training is more effective at reducing pain responses in non-Hispanic Blacks compared to non-Hispanic Whites. The investigators are interested in comparing regular aerobic exercise training versus high-intensity interval training.

Study Overview

Status

Withdrawn

Conditions

Intervention / Treatment

Detailed Description

Racial discrepancy in the experience of pain is well documented within the literature. Non-Hispanic Blacks (NHB) report greater amounts and severity of clinical pain compared to non-Hispanic Whites (NHW) in a variety of clinical conditions. NHB also experience greater pain-related symptoms and disability, regardless of descriptive factors such as age, gender, and socioeconomic status or clinical factors such as comorbidities and duration of disease. Further, NHB tend to be medically undertreated for pain, regardless of nearly identical reporting of pain level and severity compared with NHW. Not only is adequate pain treatment infrequent, but many pain treatments are less effective in NHB than in NHW, commonly resulting in less reduction of pain severity in this population.

In comparison to NHW, NHB report greater sensitivity to several types of pain, including heat pain, cold pressor pain, ischemic pain, and electrical stimulation. NHB show increased temporal summation, implying central nervous system hypersensitivity and hyperexcitability to noxious (painful) stimuli. Specifically, regarding experimental heat pain, NHB differ minimally in pain threshold or ratings of pain intensity compared to NHW, but perceive greater unpleasantness of pain and show a lower pain tolerance. The physiological mechanisms underlying this racial discrepancy remain unknown.

Experimental pain assessment is valuable in understanding the experience of pain between individuals. Pain is an individual experience and differs from one to another. However, differences in experimental pain perceived may estimate the clinical pain one would experience. Studies show that greater experimental pain sensitivity is associated with greater experience of day-to-day pain in healthy adults and can predict higher levels of clinical pain in adult patients.

While affective (subjective) pain perception has been the focus of the majority of pain assessment studies, in 2008 Campbell et al. investigated the nociceptive flexion reflex (NFR), an involuntary and objective component of the pain response. The NFR is a spinal-mediated reflex that follows activation of nociceptive A-delta afferents by noxious stimuli. This study shows the NFR threshold in NHB is decreased compared to NHW, implying a physiological difference between these racial groups that may contribute to the discrepancy in pain perception. Skin blood flow via vasodilation, another physiological measure, has been shown to increase in response to noxious thermal stimuli in order to distribute heat away from a singular point in the cutaneous environment and prevent damage. Assessing changes in skin blood flow in response to noxious thermal stimuli may further elucidate physiological differences between races that affect pain perception.

It is important to investigate more effective prevention or treatment methods for pain in NHB. Exercise-induced hypoalgesia (EIH) is characterized by decreased pain sensation following physical exercise. Specifically, EIH leads to decreased sensitivity to noxious (painful) stimuli, increased pain thresholds, increased pain tolerance, and decreased pain ratings. EIH has been shown to occur following several types of exercise, such as acute bouts of submaximal, continuous aerobic exercise and acute bouts of isometric hand-grip exercise. Lending to the knowledge of racial discrepancy in pain perception, a study by Umeda et al. in 2016 showed NHB had a smaller magnitude of EIH compared to NHW following isometric hand-grip exercise, but racial differences in EIH remain incompletely understood.

It is suggested that hypoalgesia following exercise may be due to an overlapping of pain perception and cardiovascular mechanisms. For example, pain regulation and blood pressure control are associated with the same brain stem nuclei. Further, hypertensive individuals have shown reduced sensitivity to noxious (painful) stimuli compared to normotensives, and acute pharmacological elevations in blood pressure have been shown to alter pain perception. Therefore, it is important to investigate alterations in pain perception following both acute (which should elicit elevations in blood pressure) and chronic (which should elicit overall declines in blood pressure) exercise.

Several studies have investigated the effects of submaximal exercise on various types of pain and it is typical to see moderate-intensity continuous (MIC) exercise incorporated into pain management programs (generally 30 minutes of 70% VO2max exercise). However, two studies in particular display data indicating that as workload increases, pain thresholds increase in a stepwise manner. Other studies show EIH occurs more consistently following exercise at higher intensities (> 70% VO2max), indicating that high intensity interval training (HIIT) may produce more beneficial results in affective and/or objective responses to pain than MIC exercise. Several studies have looked at affective pain perception following acute submaximal bouts of aerobic and isometric exercise. Those that have investigated acute HIIT have only examined affective responses. The investigators do not know of any studies that have looked at the acute and chronic effect of MIC exercise and HIIT on affective and objective pain perception in NHB and NH There are three main purposes of this study, and they are as follows: 1) to assess objective and subjective responses to pain in NHB and NHW, 2) to assess the use of acute versus chronic exercise in pain management for NHW and NHB, and 3) to assess the use of MIC exercise versus HITT in pain management for NHW and NHB. The investigators hypothesize that 1) NHB will show decreased skin blood flow response to noxious stimuli compared to NHW prior to exercise training, 2) NHB will report greater pain ratings than NHW prior to exercise training, and 3) chronic HIIT will mitigate the differences in skin blood flow and pain ratings between NHB and NHW.

Study Type

Interventional

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • Georgia
      • Atlanta, Georgia, United States, 30303
        • Georgia State University

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years to 40 years (ADULT)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • Healthy
  • Normotensive
  • Identify as non-Hispanic Black or non-Hispanic White
  • Healthy enough to participate in regular exercise
  • Not taking any medications other than birth control

Exclusion Criteria:

  • Heart disease (high blood pressure, previous stroke or heart attack)
  • Type 1 or 2 diabetes
  • History of cancer treated with chemotherapy
  • History of nerve damage
  • History of chronic pain
  • Current smoker/tobacco user or quit less than 1 year ago
  • Skin disorders (psoriasis, etc.)
  • Pregnant
  • Taking any medications other than birth control

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: BASIC_SCIENCE
  • Allocation: RANDOMIZED
  • Interventional Model: FACTORIAL
  • Masking: NONE

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
EXPERIMENTAL: Aerobic Exercise Training
Moderate intensity (75% heart rate reserve) cycling exercise for 32 minutes, 3 days per week for 5 weeks
Other: Aerobic Exercise Training
Traditional, continuous aerobic exercise (cycling) at a moderate intensity
EXPERIMENTAL: Interval Training
High intensity (95% heart rate reserve) cycling exercise for 20 minutes, 3 days per week for 5 weeks
Other: Interval Training
High-intensity interval exercise consisting of short bursts of exercise interspersed with rest periods
NO_INTERVENTION: Control
Control (no exercise intervention) group

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in skin blood flow response to local heating
Time Frame: Baseline (prior to intervention or control) and at the conclusion of the 5-week intervention or control. The post-intervention assessment will be performed no later than 3-5 days after completion of the 5-week intervention or control.
Vasodilation in response to painful and non-painful heating of the skin
Baseline (prior to intervention or control) and at the conclusion of the 5-week intervention or control. The post-intervention assessment will be performed no later than 3-5 days after completion of the 5-week intervention or control.

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Georgia State University

Investigators

  • Principal Investigator: Brett J Wong, Ph.D., Georgia State University

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (ANTICIPATED)

February 1, 2019

Primary Completion (ANTICIPATED)

December 1, 2019

Study Completion (ANTICIPATED)

December 1, 2019

Study Registration Dates

First Submitted

July 11, 2018

First Submitted That Met QC Criteria

July 25, 2018

First Posted (ACTUAL)

August 1, 2018

Study Record Updates

Last Update Posted (ACTUAL)

December 11, 2018

Last Update Submitted That Met QC Criteria

December 8, 2018

Last Verified

December 1, 2018

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • R01HL141205 (NIH)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

The current approved IRB and informed consent state that we will not share participants' data except with applicable oversight bodies (IRB, FDA, OHRP, etc.).

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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