Breath test to measure muscle sensitivity in young and older adults

The Efficacy of a Non-Invasive 13CO2 'Breath Test' to Detect Anabolic Resistance Following Step Reduction in Younger and Older Adults

NA · University of Toronto · NCT05216809

This study is testing a breath test to see how aging and changes in activity levels affect how well young and older adults respond to protein and exercise.

Quick facts

PhaseNA
Study typeInterventional
Enrollment32 (estimated)
Ages18 Years to 80 Years
SexAll
SponsorUniversity of Toronto (other)
Locations1 site (Toronto, Ontario)
Trial IDNCT05216809 on ClinicalTrials.gov

What this trial studies

This study investigates the use of a non-invasive 13CO2 breath test to evaluate differences in anabolic sensitivity between young and older adults after periods of habitual and reduced physical activity. Participants will undergo a series of sessions, including an introductory video call and body composition assessments, to gather data on their physical activity levels and body composition. The focus is on understanding how aging and changes in activity levels affect the body's response to dietary protein and exercise. The study aims to provide insights into anabolic resistance, which is a common issue in older adults.

Who should consider this trial

Good fit: Ideal candidates are healthy young adults aged 18-35 and older adults aged 60-80 who are physically active with a daily step count greater than 7,000.

Not a fit: Patients with chronic illnesses, recent cancer, or those using certain medications may not benefit from this study.

Why it matters

Potential benefit: If successful, this study could lead to improved strategies for enhancing muscle health and preventing sarcopenia in older adults.

How similar studies have performed: While the specific use of a 13CO2 breath test is novel, related studies on anabolic sensitivity and aging have shown promising results.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Healthy young (age: 18-35 years) or older (age: 60-80 years) adults
* Average daily step-count \>7,000/day
* BMI between normal to overweight (18.5-29.9 kg/m2)

Exclusion Criteria:

* Regular use of nonsteroidal anti-inflammatory drugs (with the exception of daily low-dose aspirin)
* Use of anticoagulants
* Use of a walker, cane, or assistive walking device
* Current or recently remised cancer
* Infectious or gastrointestinal disease
* Inability to comply with study protocol (e.g., \>2,000 steps/day during Step-Reduction Phase)
* Regular tobacco use
* Self-reported illicit drug use (e.g. growth hormone, testosterone, etc.)
* Diagnosed chronic illness (e.g. type 2 diabetes, heart disease, thyroid disease)
* Pregnant
* Hormonal Replacement Therapy

Where this trial is running

Toronto, Ontario

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.

View on ClinicalTrials.gov →

Conditions: Sedentary Behavior, Aging, Sarcopenia, Amino Acids, Dietary Protein, Skeletal Muscle, Step-Reduction, Anabolic Resistance

Last reviewed 2026-05-15 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.