The Influence of Cerebral Blood Flow and PETCO2 on Neuromuscular Function During Passive Heat Stress

NCT ID: NCT01848665

Last Updated: 2018-01-29

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: PHASE4
• Total Enrollment: 8 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2013-05-31
• Study Completion Date: 2016-12-31

Brief Summary

Increased core temperature (hyperthermia) has been associated with impaired neuromuscular performance; however, the mechanisms associated with these performance decrements and their potential synergies remain unclear. While the majority of research suggests that the observed fatigue is related to the central nervous system, the influence of changes in cerebral blood flow (CBF) and associated changes in cerebral alkalosis (estimated by end-tidal partial pressure of carbon dioxide; PETCO2) remains unexamined. In response to hyperthermia, humans hyperventilate as means of heat dissipation, resulting in a hypocapnia (reduced PETCO2) mediated decrease in CBF and consequently, cerebral alkalosis (increased cerebral pH). Previous research suggests that hyperventilation induces changes in neural excitability and synaptic transmission; however, it remains unclear if these changes are related to hypocapnia mediated decrease in CBF or decreased PETCO2 or both.

The purpose of the proposed research program is to examine the influence of changes in CBF and cerebral alkalosis on neuromuscular function during passive heat stress. The research project will consist of 3 separate experimental trials: (a) poikilocapnic hyperthermia (increased core temperature; decrease CBF; decrease PETCO2), (b) isocapnic hyperthermia (increased core temperature; no change CBF; no change PETCO2) and (c) isocapnic hyperthermia + indomethacin (increased core temperature; decrease CBF; no change PETCO2). During each manipulation, neuromuscular function will be evaluated and compared to baseline (normothermic) conditions using a repeated measures design.

It is hypothesized that changes in PETCO2 and therefore, changes in cerebral alkalosis will contribute to neuromuscular fatigue independent of changes in CBF or increases in core temperature.

Conditions

Healthy Males; Neuromuscular Function

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: SINGLE_GROUP
• Primary Study Purpose: BASIC_SCIENCE
• Blinding Strategy: SINGLE

Study Groups

Drug

Indomethacin, 1.2 mg kg 1 dose

Group Type: EXPERIMENTAL

Indomethacin

Intervention Type: DRUG

Placebo

generic flour placebo capsule

Group Type: PLACEBO_COMPARATOR

Placebo

Intervention Type: DRUG

Interventions

Indomethacin

Intervention Type: DRUG

Placebo

Intervention Type: DRUG

Eligibility Criteria

Inclusion Criteria

• 18 to 45 yrs old; healthy males

Exclusion Criteria

• diagnosed medical condition; NSAID allergy; smoker; high altitude exposure; implants

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 45 Years
• Eligible Sex: MALE
• Accepts Healthy Volunteers: Yes

Sponsors

Brock University

OTHER

Sponsor Role: lead

Responsible Party

Stephen Cheung

Professor

Responsibility Role: PRINCIPAL_INVESTIGATOR

Locations

Brock University

St. Catharines, Ontario, Canada

Countries

Canada

Other Identifiers

EEL 073.3

Identifier Type: -

Identifier Source: org_study_id