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Completed

NCT Number: NCT00946933

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

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.

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Key information

Conditions

Healthy Behavior Dyspnea Motor Activity Pathological Conditions, Signs and Symptoms Respiration Disorders Respiratory Tract Diseases Signs and Symptoms Signs and Symptoms, Respiratory

Age range

20 year–80 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Respiratory Investigation Unit at Kingston General Hospital

Kingston, Ontario, K7L 2V7, Canada

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

NH4Cl (ammonium chloride)

Dietary Supplement

0.2 g/kg/day of NH4Cl (ammonium chloride)

Placebo

Dietary Supplement

0.025 g/kg/day of NaCl (sodium chloride)

Primary outcomes

  1. Breathlessness intensity (10-point Borg scale)

    Time frame: Measured at the end of each 3 day treatment period

Secondary outcomes

  1. Exercise capacity (peak VO2)

    Time frame: Measured at the end of each 3 day treatment period

Sponsors and collaborators

Lead sponsor

Queen's University

Other

Registry information

Official study title

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

Important dates

Study start
2009
Primary completion
2010
Study completion
2010
First posted
Jul 27, 2009
Registry last updated
Dec 17, 2012

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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