The aim of this randomized controlled trial is to: Phase I: To explore, in a first pilot phase, the adequate combination of hypoxia severity and exercise intensity in patients with symptomatic lower extremity artery disease (LEAD). Acute walking performances and physiological responses (vascular and muscular) to a normobaric hypoxic exercise performed will be assessed at two different altitudes (1500 m and 2500 m).
The results of this first phase will then be used to determine the optimal hypoxic level for the exercise training program which will be assessed during the Phase II.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
SINGLE
Enrollment
20
Subjects will perform a 6-min treadmill exercise wearing an oronasal mask connected (through a hose) with a three-way valve to an altitude simulation device (Altitrainer; SMTech, Nyon, Switzerland). The ambient air will be mixed with nitrogen and inspired oxygen fraction will be reduced to 16%. The first 3 min will be performed at 70% of the mean speed calculated during a previous visit, and the last 3 min at an intensity between 12-14 on the Borg's scale.
Subjects will perform a 6-min treadmill exercise wearing an oronasal mask connected (through a hose) with a three-way valve to an altitude simulation device (Altitrainer; SMTech, Nyon, Switzerland). The ambient air will be mixed with nitrogen and inspired oxygen fraction will be reduced to 14%. The first 3 min will be performed at 70% of the mean speed calculated during a previous visit, and the last 3 min at an intensity between 12-14 on the Borg's scale.
CHUV
Lausanne, Canton of Vaud, Switzerland
RECRUITINGWalking performance
Total walking distance (in meters) during the 6 min treadmill test
Time frame: After each 6 min treadmill test performed under hypoxic condition (1500 and 2500 m) and under normoxic condition (i.e., average of 3 weeks; one condition per week)
Pain free walking time
Pain free walking time during the 6 min treadmill test
Time frame: After each 6 min treadmill test performed under hypoxic condition (1500 and 2500 m) and under normoxic condition (i.e., average of 3 weeks; one condition per week)
Muscle oxygenation during exercise
Muscle oxygenation during the 6 min treadmill test (assessed by near-infrared spectroscopy)
Time frame: After each 6 min treadmill test performed under hypoxic condition (1500 and 2500 m) and under normoxic condition (i.e., average of 3 weeks; one condition per week)
Pulse wave velocity
Pulse wave velocity before and after the 6 min treadmill test
Time frame: Before and after each 6 min treadmill test performed under hypoxic condition (1500 and 2500 m) and under normoxic condition (i.e., average of 3 weeks; one condition per week)
Flow-mediated dilation
Flow-mediated dilation before and after the 6 min treadmill test
Time frame: Before and after each 6 min treadmill test performed under hypoxic condition (1500 and 2500 m) and under normoxic condition (i.e., average of 3 weeks; one condition per week)
Pulse oxygen saturation
Pulse oxygen saturation during the 6 min treadmill test
Time frame: After each 6 min treadmill test performed under hypoxic condition (1500 and 2500 m) and under normoxic condition (i.e., average of 3 weeks; one condition per week)
This platform is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional.
Subjects will perform a 6-min treadmill exercise wearing an oronasal mask connected (through a hose) with a three-way valve to an altitude simulation device (Altitrainer; SMTech, Nyon, Switzerland). For the exercise performed in normoxia conditions, subjects will breathe room air. The first 3 min will be performed at 70% of the mean speed calculated during a previous visit, and the last 3 min at an intensity between 12-14 on the Borg's scale.
Ankle-brachial index
Ankle-brachial index before and after the 6 min treadmill test
Time frame: Before and after each 6 min treadmill test performed under hypoxic condition (1500 and 2500 m) and under normoxic condition (i.e., average of 3 weeks; one condition per week)
Toe-brachial index
Toe-brachial index before and after the 6 min treadmill test
Time frame: Before and after each 6 min treadmill test performed under hypoxic condition (1500 and 2500 m) and under normoxic condition (i.e., average of 3 weeks; one condition per week)
Rate of perceived exertion
Rate of perceived exertion (RPE) will be assessed using Borg's scale. RPE is a widely used and reliable indicator to monitor and guide exercise intensity. The scale allows individuals to subjectively rate their level of exertion during 6 min treadmill test. Patients will classify their RPE between 6 (light) and 20 (maximal).
Time frame: After each 6 min treadmill test performed under hypoxic condition (1500 and 2500 m) and under normoxic condition (i.e., average of 3 weeks; one condition per week)
Leg pain
Leg pain during exercise will be measured with a 10-points (0: "no pain" and 10: "worst imaginable pain") visual analogic scale (VAS).
Time frame: After each 6 min treadmill test performed under hypoxic condition (1500 and 2500 m) and under normoxic condition (i.e., average of 3 weeks; one condition per week)