Pulmonary Disease, Chronic Obstructive
Conditions
Keywords
Pulmonary Disease, Chronic Obstructive, Muscle fatigue, Energy metabolism, Muscle oxygenation
Brief summary
The purpose of this study is to investigate whether a localized exercise, in which cardiorespiratory demand is reduced, will result in greater limb muscle fatigue in patients with COPD as a consequence of muscle oxygenation and muscle metabolism disturbances.
Interventions
OTHERFatiguing exercise
All participants (patients and healthy subjects) will perform the exercise both under normoxic (FiO2 = 0.21) and hyperoxic conditions (FiO2 = 100%)
Sponsors
Canadian Lung Association
Laval University
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
BASIC_SCIENCE
Masking
SINGLE (Subject)
Eligibility
Sex/Gender
ALL
Age
50 Years to 75 Years
Healthy volunteers
Yes
Inclusion criteria
* COPD (FEV1/FVC \< 0.70 and FEV1 \< 0.80 predicted * Healthy subjects: no evidence of airways obstruction (FEV1/FVC \> 0.70 and FEV1 \> 0.80 predicted) * Smoking history \> 15 pack-years
Exclusion criteria
* Chronic hypoxemia and/or hypercapnia (PaO2 \< 60 mmHg or SpO2 \< 88% at rest and/or PaCO2 \> 45 mmHg) * Recent exacerbation (\< 3 months) * Recent cancer (\< 3 years) * Diabetes * Myopathy, neuromuscular or articular disease * Unstable cardiac disease * Absolute contraindications to exercise testing * Regular physical activity or exercise training program in the last 2 months * Physical activity score \> 9 in the Voorips questionnaire * Thigh skinfold thickness \> 15 mm * BMI \> 30
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Muscle deoxygenation | 45 seconds post-exercise (knee-extension repetitions) | Changes of deoxyhemoglobin/myoglobin concentrations measured by near-infrared spectroscopy of vastus lateralis muscle. |
| Muscle metabolism | 45 seconds post-exercise (knee extension repetitions) | Changes in glycolytic and oxidative metabolism pathway markers, energy substrates (glycogen and glucose), end-products of glycolysis (pyruvate, and lactate), intermediate markers of glycolysis and high-energy phosphate compounds obtained from muscle biopsies |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Ventilatory response | Baseline, beginning and end of each serie of knee extensions (fatiguing exercise) | Minute ventilation will be monitored during the fatigue-inducing exercise and it will be compared between subjects and conditions (FiO2 = 21% vs. FiO2 = 100%) |
| Quadriceps muscle fatigue | baseline, 15 min and 40 min after the fatigue-inducing exercise | Quadriceps muscle fatigue will be determined by loss of quadriceps strength measured by magnetic stimulation after the fatigue-inducing exercise. Surface electromyography will also be measured to characterize muscle fatigue. |
| total muscle work | end of fatiguing exercise | Total muscle work performed during fatigue-inducing exercise that will be composed by subsequent isokinetic knee-extensions repetitions at 40% of maximal peak torque |
Countries
Canada
Contacts
Primary ContactFernanda Ribeiro, PhD candidate
Outcome results
None listed