Clinical Trial Details
— Status: Terminated
Administrative data
NCT number |
NCT05095311 |
Other study ID # |
10766 |
Secondary ID |
|
Status |
Terminated |
Phase |
Phase 4
|
First received |
|
Last updated |
|
Start date |
May 19, 2021 |
Est. completion date |
April 27, 2022 |
Study information
Verified date |
February 2024 |
Source |
Indiana University |
Contact |
n/a |
Is FDA regulated |
No |
Health authority |
|
Study type |
Interventional
|
Clinical Trial Summary
Exercise-induced arterial hypoxemia (EIAH), a reduced amount of oxygen in the arterial blood
during exercise, has been observed in otherwise healthy, highly-trained endurance athletes
during exercise at sea level. The extent of the arterial deoxygenation may be influenced by a
histamine-mediated inflammatory response at the pulmonary capillary-alveolar membrane
limiting oxygen diffusion. Moreover, while EIAH has been routinely explored in running and
cycling, swimming is understudied despite potential mechanistic avenues which may put
swimmers at further risk for EIAH. The purpose of this study is threefold: 1) to determine
whether highly-trained swimmers experience EIAH during submaximal and maximal exercise, 2) to
determine the extent to which histamine release influences oxyhemoglobin saturation during
swimming exercise, and 3) to determine whether cetirizine HCl (CH), an H1-receptor
competitive inhibitor, can improve oxyhemoglobin saturation during submaximal and maximal
swimming exercise. Twenty-four (12 men, 12 women) highly-trained swimmers will complete an
intense swimming protocol to assess the histamine response to intense exercise. A subset with
the highest histamine responses will participate in three additional sessions (placebo, NS,
and CH conditions) which will include a swimming aerobic capacity test and 5-minutes of
swimming at both 70 and 85% of their maximal oxygen uptake.
Description:
For the first testing session, participants will report to the Indiana University Human
Performance Laboratory to complete a medical screening and, if willing, consent to the
procedures of the study. The medical screening will include measurements of height, weight,
resting heart rate, resting blood pressure, and resting pulmonary function along with a
health history questionnaire.
The second testing session consists of an assessment of risk factors for development of EIAH,
specifically changes in blood biomarkers pre- and post-swimming exercise. Participants will
report to the Counsilman-Billingsley Aquatics Center and complete an exercise protocol
designed to elicit an inflammatory response. Venous blood draws will be performed to assess
participants' pre-exercise complete blood count and pre- and post-intense exercise
concentrations of plasma IL-1β, IL-8, plasma histamine, whole blood histamine, and histamine
release. Measurements of hemoglobin concentration and hematocrit will also be performed pre-
and post-exercise in order to correct biomarker concentrations for fluid loss during
exercise. Swimmers of each sex that exhibit the largest histamine release will be selected
for further study until at least four swimmers of each sex complete all three experimental
trials.
Twelve swimmers (n = 6 men, n = 6 women) will be selected for further trials. Those selected
for further study will visit the Human Performance Laboratory on two occasions separated by
at least 48 hours and no more than 60 days. Apart from receiving a placebo (PL) or drug
treatment (cetirizine HCl, CH) prior to exercise, participants will perform identical
protocols on each visit to the laboratory. Participants will report to the lab and consume
either a placebo or CH pill, followed by a health history update questionnaire and their
resting pulmonary function will be measured. Participants will then complete a self-selected
warm-up that will be standardized across all testing sessions, followed by instrumentation.
The exercise protocol beings with a progressive swimming test to maximum aerobic capacity
(V̇O2max) in a swimming flume, followed by two constant load work bouts at approximately 70
and 85% of the previously recorded HRmax while peripheral capillary oxyhemoglobin saturation
(SpO2) is continuously monitored. Participants will receive a 20-min break between each work
bout. Drug treatments will be assigned in a double-blind, randomized crossover fashion such
that each participant receives each treatment. Concentrations of plasma histamine, whole
blood histamine, and histamine release will be assessed from pre- and post-exercise blood
samples.