Histamine Blockers for Exercise-Induced Blood Flow
What You Need to Know Before You Apply
What is the purpose of this trial?
This trial aims to assess how blocking histamines, which are molecules involved in allergy responses, affects blood flow in the lungs after exercise. Participants will take either a placebo or diphenhydramine hydrochloride, a common antihistamine, before exercising. The trial is suitable for healthy, non-smoking individuals without diagnosed heart, lung, or metabolic conditions. Participants must be willing to visit the lab three times during the study. As an unphased trial, it offers participants an opportunity to contribute to scientific understanding of exercise and lung health.
Do I have to stop taking my current medications to join the trial?
Yes, you must stop taking your current medications, including oral contraceptives, to participate in this trial.
Is there any evidence suggesting that this trial's treatments are likely to be safe?
Research shows that diphenhydramine hydrochloride, a common ingredient in allergy medicines, is generally safe for use. Most people tolerate it well, and its side effects, such as drowsiness or dry mouth, are well-known.
However, taking excessive amounts can lead to more serious issues, like restlessness or heart problems. These effects are rare and usually occur only with very high doses, not the amounts typically used in studies.
Since the FDA has approved diphenhydramine for treating allergies, there is extensive experience with its safety in people. This provides reassurance about its use in the study, although researchers are still examining its effects on blood flow in the lungs after exercise.12345Why are researchers excited about this trial?
Researchers are excited about using diphenhydramine hydrochloride, an antihistamine, for exercise-induced blood flow because it targets histamine H1 receptors, which play a role in regulating blood flow during exercise. Unlike current treatments that primarily focus on cardiovascular fitness and hydration, this approach directly modulates the biochemical pathways influencing blood flow. By blocking histamine receptors, this treatment has the potential to improve exercise performance and recovery in ways traditional methods do not address.
What evidence suggests that histamine blockers are effective for exercise-induced blood flow?
Research has shown that blocking histamine, a molecule often linked with allergies, can change blood flow after exercise. Specifically, diphenhydramine hydrochloride, an antihistamine, reduces the usual increase in blood flow that occurs post-exercise. This trial will compare the effects of a placebo with those of diphenhydramine hydrochloride on exercise-induced blood flow. Some studies suggest that antihistamines during endurance training can lead to smaller fitness improvements. However, other research found that diphenhydramine can help reduce breathing problems during exercise for well-trained athletes. Overall, researchers continue to study the effects of diphenhydramine on blood flow and lung function during and after exercise.26789
Are You a Good Fit for This Trial?
This trial is for individuals who are interested in how exercise affects blood flow, especially after working out. It's not clear if you have any specific health conditions that need to be met or avoided to participate.Inclusion Criteria
Exclusion Criteria
Timeline for a Trial Participant
Screening
Participants are screened for eligibility to participate in the trial
Treatment
Participants will ingest either a placebo or histamine H1 receptor blockade before performing an exercise bout
Follow-up
Participants are monitored for changes in pulmonary and systemic hemodynamics post-exercise
What Are the Treatments Tested in This Trial?
Interventions
- Diphenhydramine hydrochloride
Trial Overview
The study is looking at the role of histamines on lung blood vessels after exercise. Participants will do an exercise bout and then receive either a placebo or Diphenhydramine (an antihistamine) to see the effects on their body.
How Is the Trial Designed?
2
Treatment groups
Experimental Treatment
Placebo Group
Participants will ingest histamine H1 receptor blockade before performing an exercise bout.
Participants will ingest a placebo before an exercise bout.
Find a Clinic Near You
Who Is Running the Clinical Trial?
University of British Columbia
Lead Sponsor
Citations
Histamines and Central Hemodynamics
When the actions of histamine, a molecule primarily known for its role in allergies, are blocked, there is an attenuated blood flow response ...
Antihistamine Does Not Affect Exercise Performance - PubMed
The effects of a single oral dose of a sedating and nonsedating H1 receptor antagonist on exercise performance and tolerance were examined in a double-blind,
Histamine is a molecular transducer of adaptation to ...
Blocking histamine's actions during endurance exercise training by taking common over-the-counter antihistamines resulted in diminished gains in fitness. These ...
Do antihistamines affect exercise performance?
When we studied recovery from exercise, we found that blood flow had increased, but if we gave histamine blockers in advance of exercise, that ...
Nedocromil sodium and diphenhydramine HCl ameliorate ...
Our data demonstrate that introduction of a histamine-targeting, anti-inflammatory agent (NS or DH) ameliorates EIAH in these highly trained runners.
Nedocromil sodium and diphenhydramine HCl ameliorate ...
Exercise‐induced arterial hypoxemia (EIAH) has been observed in highly trained endurance athletes during near maximal exercise, ...
Material Safety Data Sheet
Diphenhydramine hydrochloride. Page 5. MATERIAL SAFETY DATA SHEET ... Toxicology and Hazard Communication. Pfizer Global Environment, Health, and Safety.
SAFETY DATA SHEET
Skin and body protection. Wear suitable protective clothing. Respiratory protection. No protective equipment is needed under normal use conditions. If exposure ...
Diphenhydramine - StatPearls - NCBI Bookshelf - NIH
Diphenhydramine overdose can cause significant toxicity and result in various sequelae, including agitation, cardiac arrhythmias, rhabdomyolysis ...
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