Effects of Iron on Exercise Capacity During Hypoxia

Phase 1

Completed

• Conditions: Healthy Volunteers
• Interventions: Drug: Normal saline; Drug: Iron sucrose.

• Registration Number: NCT01265108
• Lead Sponsor: University of Oxford

Brief Summary

During alveolar hypoxia, for example at high altitude or in patients with respiratory disease, there is evidence to suggest that hypoxia-induced pulmonary hypertension might limit exercise performance. Intravenous iron supplementation has recently been shown to reverse pulmonary hypertension in healthy humans at high altitude, and to prevent pulmonary hypertension in volunteers exposed to hypoxia at sea level. The investigators hypothesized that intravenous iron supplementation would enhance exercise capacity during alveolar hypoxia.

Detailed Description

Not available

Study Timeline

• Study Start: 2010-11
• Study First Submitted: 2010-12-21
• Study First Submitted QC: 2010-12-21
• Study First Posted: 2010-12-22
• Primary Completion: 2015-01
• Study Completion: 2015-04
• Status Verified: 2015-07
• Last Update Submitted: 2015-07-27
• Last Update Posted: 2015-07-29

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 12

Inclusion Criteria

• Age between 18 and 60 years
• Sea level natives with no recent exposure to high altitude
• Baseline iron indices within the normal range
• Detectable tricuspid regurgitation on echocardiography

Exclusion Criteria

• Significant cardiorespiratory disease
• Known susceptibility to high altitude-related illness
• Taking medications or iron supplementation
• Pregnancy

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: CROSSOVER

Arm && Interventions

Group	Intervention	Description
Intravenous normal saline	Normal saline	Infusion of 100 ml normal (0.9%) saline.
Intravenous iron sucrose	Iron sucrose.	Infusion of 200 mg iron sucrose (Venofer) in 100 ml normal (0.9%) saline.

Primary Outcome Measures

Name	Time	Method
Maximal exercise capacity during hypoxia, assessed by maximal oxygen consumption.	After 8-h exposure to alveolar hypoxia.	Volunteers will receive either intravenous iron or saline placebo, before exposure to 8 hours of alveolar hypoxia. They will then undergo an exercise test while breathing an hypoxic gas mixture. The primary outcome measure will be exercise capacity as determined by maximal oxygen consumption during this test. Volunteers will receive both interventions, via a crossover design. Due to uncertainty about the duration of action of iron at a cellular level, all volunteers will receive saline infusion on the first study day, and iron sucrose infusion on a second study day, at least one week later.

Secondary Outcome Measures

Name	Time	Method
Maximal exercise capacity, assessed by peak power output.	After 8-h exposure to alveolar hypoxia.
Pulmonary artery systolic pressure.	After 8-h exposure to alveolar hypoxia.
Blood levels of oxygen-regulated proteins.	After 8-h exposure to alveolar hypoxia

Trial Locations

Locations (1)

Department of Physiology, Anatomy & Genetics, University of Oxford; 🇬🇧 Oxford, United Kingdom