Effects of Respiratory Muscle Training on Tongue Muscle Function

Effects of Respiratory Muscle Training on Tongue Muscle Function in Healthy Subjects, a Randomized Controlled Trial.

This study aims to investigate the effects of respiratory muscle training on tongue muscle function in healthy subjects. We hypothesize that respiratory muscle training can improve strength and endurance of the tongue muscles.

In patient with obstructive sleep apnea, studies have shown that respiratory muscle training improved sleep-related outcomes in patients with obstructive sleep apnea (OSA). On the other hand, a recent study showed that expiratory muscle training improved tongue motor strength in patients with OSA. We hypothesize that respiratory muscle training (either Inspiratory Muscle Training (IMT) or Expiratory Muscle Training (EMT)) may elicit sleep-related improvement in patient with OSA through enhancement on tongue muscle function.

To investigate our hypothesis, we will first address this question in a population of healthy subjects. This study will therefore investigate the effects of respiratory muscle training on tongue muscle function in healthy subjects. The primary hypothesis is that the IMT program with lead to an increase in tongue strength compared to the control group. Other hypothesizes are that EMT, but not sham, will also lead to an increase in tongue strength, compared to the control group.

Inclusion Criteria:

Community ambulant adults between 18 to 65 years old as of testing day; able to understand French or Dutch (depending on the study's site of inclusion); BMI ≥ 18 and ≤ 30 kg/m².

Exclusion Criteria:

Any diagnosed neuromuscular or cardiorespiratory disease; diagnosed psychiatric or psychological disorders which could affect adherence to or comprehension of instructions; diagnosed eating disorders; previous or ongoing head and neck cancer; diagnosed OSA; presenting a high-risk of sleep-disordered breathing indicated by a NoSAS score of 8 or higher 32 or a STOP-Bang score of 3 or higher 33,34; resting heart rate (HR) > 100 beats per minute (bpm) or < 50 bpm; resting systolic blood pressure (SBP) > 140 or < 90 mmHg, diastolic blood pressure (DBP) > 90 or < 50 mmHg; oxygen saturation (SpO2) < 94% at rest on room air. Individuals with abnormal lung function, i.e., forced expiratory volume in 1 second (FEV1) ≤ 80%, forced vital capacity (FVC) ≤ 80%, and FEV1/FVC ≤ 70%, will also be excluded.