Endurance Performance at Altitude

NCT03710369 | Completed

• 1 other identifier: H14-01736
• Study Type: interventional
• Target: 10
• Locations: 1 country
• Sites: 1

Brief Summary

The degree to which endurance exercise performance is diminished in acute hypoxia is variable and appears to be the result of several different physiological processes, however this research focuses on hypoxic pulmonary vasoconstriction (HPV). Sildenafil, a pulmonary vasodilator, has been used with mixed results to improve athletic performance in hypoxia. Because sildenafil has been shown to reduce HPV in some individuals, we believe that its effectiveness is closely related to the magnitude of the HPV response and the degree that individual exercise performance declines in hypoxia. This research will investigate the relationship between sildenafil, HPV, and exercise performance.

Conditions

Altitude; Hypoxia; Sildenafil; Exercise

Outcome Measures

Primary Outcomes (1)

• Performance in completion of Time Trial task

  Performance is measured as the mean power output achieved during the time trial task.

  20 minutes after test.

Secondary Outcomes (1)

• PAP measured with ultrasound during exercise.

  20 minutes after test.

Study Arms (2)

Normoxia

SHAM COMPARATOR

Exercise in room air (normoxia). Sildenafil

Drug: Sildenafil

Hypoxia

ACTIVE COMPARATOR

Exercise in hypoxic air (reduced O2 concentration) that simulates 2500m elevation for 30-40 minutes with Sildenafil. Placebo

Drug: Placebo; Drug: Sildenafil

Interventions

Placebo DRUG

The placebo pill was compounded by McDonalds Pharmacy.

Also known as: McDonalds Pharmacy

Hypoxia

Sildenafil DRUG

Sildenafil from Pfizer, compounded by McDonalds Pharmacy.

Also known as: Pfizer

Hypoxia; Normoxia

Eligibility Criteria

• Age: 19 Years - 40 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• between age 19 (18 if a University of British Columbia student) and 40
• healthy
• competitive cyclist (hold current racing license of professional, category 1, or 2 or have a measured VO2max greater than 60 ml.min.kg).

You may not qualify if:

• smokers
• anyone unable to complete the exercise protocol
• individuals with a history of cardiovascular or respiratory illness
• those with an atrial or ventricular septal defect (e.g. patent foramen oval)
• anyone currently prescribed sildenafil, tadalafil, vardenafil or any other PDE-5 inhibiting medication
• anyone who has lived more than 15 days at moderate altitude in the last three months

Sponsors & Collaborators

• University of British Columbia: lead

Study Sites (1)

University of British Columbia - Environmental Physiology Laboratory

Vancouver, British Columbia, V6T1z1, Canada

Location

MeSH Terms

Conditions

Hypoxia; Motor Activity

Interventions

Sildenafil Citrate

Condition Hierarchy (Ancestors)

Signs and Symptoms, Respiratory; Signs and Symptoms; Pathological Conditions, Signs and Symptoms; Behavior

Intervention Hierarchy (Ancestors)

Sulfonamides; Amides; Organic Chemicals; Sulfones; Sulfur Compounds; Piperazines; Heterocyclic Compounds, 1-Ring; Heterocyclic Compounds; Purines; Heterocyclic Compounds, 2-Ring; Heterocyclic Compounds, Fused-Ring

Study Officials

• Eric Carter, MSc

  UBC

  STUDY DIRECTOR

• Michael Koehle, MD, PhD

  UBC

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: PARTICIPANT
• Purpose: BASIC SCIENCE
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Dr. Michael Koehle

Study Record Dates

• First Submitted: November 23, 2015
• First Posted: October 18, 2018
• Study Start: November 1, 2015
• Primary Completion: October 1, 2018
• Study Completion: October 2, 2018
• Last Updated: October 18, 2018

Record last verified: 2018-10

Locations

CA (1)