NCT00946933

Effects of Chronic Acid-Base Changes on Ventilatory and Perceptual Responses

Effects of Chronic Acid-Base Changes on the Ventilatory and Perceptual Response to Hypercapnia, Hypoxia and Exercise in Healthy Older Adults

• Status: Completed
• Phase: N/A
• Study type: Interventional
• Enrollment: 20 (actual)
• Sponsor: Queen's University · Academic / Other
• Sex: All
• Age: 20 Years – 80 Years
• Healthy volunteers: Accepted

Summary

Approximately 30% of people aged 65 years and older experience breathlessness (perceived respiratory difficulty) during daily activity. The main causes of increased breathlessness in the healthy elderly are poorly understood and are the main focus of the proposed study. Some possible contributing factors include abnormalities in the control and/or mechanics of breathing. To evaluate these possible contributory factors, the investigators will compare ventilatory and perceptual responses to: 1) exercise, 2) increased levels of inspired carbon dioxide, and 3) reduced levels of inspired oxygen under strictly-controlled experimental conditions where the investigators increase or decrease breathing requirements by altering dietary salt intake in healthy 40-80 year old men and women. Exercise and rebreathing tests will be performed at baseline and at the end of each 3 day treatment period. Breathlessness intensity will be measured and compared at a standardized work rate, ventilation or end-tidal PCO2 during these tests.

Conditions

• Healthy

Interventions

Type	Name	Description
DIETARY_SUPPLEMENT	NH4Cl (ammonium chloride)	0.2 g/kg/day of NH4Cl (ammonium chloride)
DIETARY_SUPPLEMENT	placebo	0.025 g/kg/day of NaCl (sodium chloride)

Timeline

• Start date: 2009-11-01
• Primary completion: 2010-09-01
• Completion: 2010-09-01
• First posted: 2009-07-27
• Last updated: 2012-12-17

Locations

1 site across 1 country: Canada