A fan blowing cool air to the face has been shown to alleviate breathlessness in malignant and non-malignant disease at rest and during exercise, however the underlying physiological mechanisms remain unknown. This random order, three-condition design study will explore physiological mechanisms of breathlessness relief with fan-to-face therapy during constant-rate exercise in people with cardiorespiratory disease.
Constant work rate tests are viewed as the most suitable and sensitive method to assess exertional breathlessness. The 4-minute constant rate treadmill test (4-min CRTT) is a validated test wherein participants exercise at an intensity determined by an incremental test. For the purpose of this study, participants will perform three 4-min CRTT under three random-order experimental conditions: (i) fan to the face; (ii) fan to the leg; (iii) no fan. The intensity of the 4-min CRTTs will be determined based on an exercise endurance test completed in a prior visit: (i) if participants have an endurance time of \<3 minutes, they will do each 4-minute CRTT at 50% of peak power output (PPO) achieved on the incremental exercise test, with a fixed grade incline of 40-50% with the speed adjusted to reach 50% PPO; (ii) if participants have an exercise endurance time of 3-8 minutes, they will do each 4-minute CRTT at 75% of peak power output (PPO) achieved on the incremental exercise test, with a fixed grade incline of 60% with the speed adjusted to reach 75% PPO; (iii) if participants have an endurance time of \>8 minutes, they will do each 4-minute CRTT at 90% of peak power output (PPO) achieved on the incremental exercise test, with a fixed grade incline of 70-80% with the speed adjusted to reach 90% PPO. This model is based on a recent study on selection of exercise endurance intensities in COPD.Cardiac and dynamic respiratory parameters will be collected breath-by-breath at rest and during exercise using the Hexokin Smart Shirt. In order to target the intranasal pathway located on the trigeminal nerve that is hypothesized to modulate the mechanisms governing the potential effectiveness of a fan to the face, a metabolic cart will be omitted due to the use of the facemask or mouthpiece and nasal clip that would block this pathway. Using the Borg 0-10 scale, rating of perceived exertion, perceptions of breathlessness intensity, unpleasantness and leg fatigue will be assessed at rest, within the last 15-seconds of each minute of exercise, and at end exercise or the symptom limited peak of exercise. Two areas of facial skin temperature, one at the forehead to target the ophthalmic branch of the trigeminal nerve and the other at the cheek to target the maxillary branch of the trigeminal nerve, will be measured prior to exercise, within the last 15-seconds of each minute of exercise, at end exercise, and following exercise using a medical grade non-contact infrared forehead thermometer. The model number of the forehead thermometer that will be used is THERMOPROPCV2 and is licensed by Health Canada and approved by the U.S. Food and Drug Administration (FDA), CE approved with European health, safety, and environmental protection standards, and approved by the Restriction of Hazardous Substances Directive (RoHS).
This is a basic, portable, household fan with a single cost of CDN$21.99.
Centre of Innovative Medicine of the McGill University Health Centre
Montreal, Quebec, Canada
RECRUITINGBorg modified 0-10 category ratio scale for breathlessness intensity
Borg modified 0-10 category ratio scale will be used to assess breathlessness intensity at end-exercise of each 4-minute constant rate treadmill test under three conditions: (i) fan to the face; (ii) fan to the leg (sham) and; (iii) no fan (control). A higher score is indicative of greater breathlessness, while a lower score is indicative of lesser breathlessness.
Time frame: End-exercise of the 4-minute constant rate treadmill test
Cardiopulmonary exercise test (4-minute constant rate) physiological response (ventilatory)
Mean ventilation (Liters/minute) will be compared across the 4-minute constant rate treadmill tests under the three different conditions: (i) fan to the face; (ii) fan to the leg (sham) and; (iii) no fan (control). A greater mean ventilation is indicative of a less efficient respiratory system, whereas a lower mean ventilation is indicative of a more efficient respiratory system.
Time frame: Averaged across the 4-minute constant rate treadmill test
Cardiopulmonary exercise test (4-minute constant rate) physiological response (operating lung volumes)
Mean operating lung volumes (i.e., inspiratory capacity in liters) will be compared across the 4-minute constant rate treadmill tests under the three different conditions: (i) fan to the face; (ii) fan to the leg (sham) and; (iii) no fan (control). A greater operating lung volume (i.e., greater inspiratory capacity) is indicative of a better and more efficient breathing pattern, while a lower operating lung volume (i.e., smaller inspiratory capacity) is indicative of a worse and less efficient breathing pattern.
Time frame: 4 serial dynamic inspiratory capacity maneuvers for each minute of the 4-minute constant rate treadmill test.
Cardiopulmonary exercise test (4-minute constant rate) physiological response (heart rate)
Mean heart rate (beats per minute) will be compared across the 4-minute constant rate treadmill tests under the three different conditions: (i) fan to the face; (ii) fan to the leg (sham) and; (iii) no fan (control). A lower heart rate is indicative of better cardiovascular fitness, while a higher heart rate is indicative of worse cardiovascular fitness.
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Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
21
Time frame: Averaged across the 4-minute constant rate treadmill test
Cardiopulmonary exercise test (3-minute constant rate) physiological response (oxygen saturation)
Mean oxygen saturation (in percentage) will be compared across the 4-minute constant rate treadmill tests under the three different conditions: (i) fan to the face; (ii) fan to the leg (sham) and; (iii) no fan (control). A lower oxygen saturation is indicative of worse health status, while a higher oxygen saturation is indicative of better health status.
Time frame: Averaged across the 4-minute constant rate treadmill test