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

This study has been completed.
Sponsor:
ClinicalTrials.gov Identifier:
NCT00946933
First Posted: July 27, 2009
Last Update Posted: December 17, 2012
The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details.
Information provided by (Responsible Party):
Dr. Denis O'Donnell, Queen's University
July 23, 2009
July 27, 2009
December 17, 2012
November 2009
September 2010   (Final data collection date for primary outcome measure)
Breathlessness intensity (10-point Borg scale) [ Time Frame: Measured at the end of each 3 day treatment period ]
Breathlessness intensity (10-point Borg scale) [ Time Frame: Baseline and measured at the end of each 5 day treatment period ]
Complete list of historical versions of study NCT00946933 on ClinicalTrials.gov Archive Site
Exercise capacity (peak VO2) [ Time Frame: Measured at the end of each 3 day treatment period ]
Exercise capacity (peak VO2) [ Time Frame: Baseline and measured at the end of each 5 day treatment period ]
Not Provided
Not Provided
 
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

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.

Not Provided
Interventional
Not Provided
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Triple (Participant, Investigator, Outcomes Assessor)
Primary Purpose: Basic Science
Healthy
  • 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)
  • Placebo Comparator: Placebo
    0.025 g/kg/day of NaCl (sodium chloride)
    Intervention: Dietary Supplement: placebo
  • Active Comparator: High salt diet
    0.2 g/kg/day of NH4Cl (ammonium chloride)
    Intervention: Dietary Supplement: NH4Cl (ammonium chloride)
Not Provided

*   Includes publications given by the data provider as well as publications identified by ClinicalTrials.gov Identifier (NCT Number) in Medline.
 
Completed
20
September 2010
September 2010   (Final data collection date for primary outcome measure)

Inclusion Criteria:

  • healthy, regularly active adults
  • non-smoking
  • BMI 18-30 kg/m2

Exclusion Criteria:

  • history of lung and/or heart disease (including cardiac arrhythmias) or other comorbidity which could interfere with proper conduct of the intervention or tests
  • hypotension or hypertension
  • hypercholesterolemia
  • sleep disordered breathing
  • inability to perform cycle exercise or comply with other testing procedures
Sexes Eligible for Study: All
20 Years to 80 Years   (Adult, Senior)
Yes
Contact information is only displayed when the study is recruiting subjects
Canada
 
 
NCT00946933
DSS-16198
No
Not Provided
Not Provided
Dr. Denis O'Donnell, Queen's University
Queen's University
Not Provided
Principal Investigator: Denis E O'Donnell, MD, FRCPC Queen's University and Kingston General Hospital
Queen's University
December 2012

ICMJE     Data element required by the International Committee of Medical Journal Editors and the World Health Organization ICTRP