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Obstructive sleep apnea (OSA) is a disorder of nighttime breathing which results in partial or complete obstruction of airflow via the upper airway or throat. Airflow limitation contributes to hypopneas more commonly known as snoring that can progress to complete airway obstruction. Obstruction is caused by the tongue blocking/obstructing the throat, and results in apnea – when airflow is prevented or blocked. Individuals with OSA experience periods of airflow limitation and/or obstruction repeatedly throughout the night. The number of snoring episodes and number of obstructions that occur per hour of sleep is referred to as the Apnea Hypopnea Index or AHI and is the rating scale of OSA severity. 

 

• An AHI < 5 events/hour of sleep is considered healthy

• An AHI between 5-15 events/hour of sleep indicates mild OSA

• An AHI of 15-30 events/hour of sleep indicates moderate OSA

• An AHI of more than 30 events/hour of sleep, is consistent with severe OSA

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Airflow limitation (snoring) and/or obstructions (apneas) are of significance because inadequate airflow contributes to lowered blood oxygen levels. If blood oxygen levels are low, your brain will detect the lowered oxygen, and alert you to wake up and resume breathing to restore oxygenation. Thus, repeated airflow limitation or obstruction result in frequent awakening during the night that in turn results in surges in blood pressure which contribute increase in blood pressure, risk for hypertension and cardiovascular disease.

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Consequences 

Obstructive sleep apnea can underlie a range of conditions that encompass mild to severe. Common side effects of obstructive sleep apnea include, daytime drowsiness, fatigue or lack of energy and difficulty concentrating. These symptoms are a result of disturbed sleep and arousal from sleep due to lowered blood oxygenation. OSA also has been identified as a key contributor to increased risk for developing high blood pressure, risk of heart attack, stroke and cardiac arrhythmias or abnormal heartbeats. Together with these heart-type problems, obstructive sleep apnea can also affect the function of the pancreas contributing to insulin resistance that is the cause of type II diabetes. In severe untreated cases, sleep apnea can lead to death.

 

Who is effected? 

Obstructive sleep apnea affects an estimated 12% of the U.S. population, and nearly 1 billion people worldwide. In general men appear more than 2-3 times more likely to have sleep apnea than women however, the incidence of OSA among women over 50 years is much higher than once thought. Women who are overweight and postmenopausal have an increased likelihood of developing OSA. OSA is also much more common among older adults. Those adults who smoke also are at an increased risk for OSA compared to nonsmokers.

 

Treatments

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Mild OSA

• Simple life style changes: 

  • Weight loss ​

  • Regular exercise 

  • Reduced alcohol consumption 

  • Stop smoking

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Taking these steps will be beneficial for reducing the risk for OSA.

 

Moderate to severe OSA:

• Continuous positive airway pressure (CPAP)

• Bilevel positive airway pressure (BiPAP)

• Auto-titrating positive airway pressure therapy 

• Mandibular device 

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Using continuous positive airway pressure or CPAP device generally is very beneficial. These “pressure” machines deliver air under positive pressure via the mouth or nose during the night which keeps the airway open and limits the likelihood of airflow limitation due to snoring or complete obstruction or apneas. Three types of positive airway pressure machines are commonly available. The most common is continuous positive airway pressure or CPAP which as its name suggests provide a continuous air or constant air pressure enough to keep the upper airway passage open. The second is BiPAP which is similar to CPAP but with this device the pressure is greater on inspiration and drops during expiration to make breathing out easier. The third option is a more recent development and referred to as auto-titrating positive airway pressure therapy. This again operates on the same principle as CPAP but the pressure level stays at a relatively low level until a change in breathing/breathing difficulty is detected and then the pressure increases to keep the airway open. Although CPAP is the most common and the most successful treatment, many people find that the masks are uncomfortable or too bulky and that wearing the mask through the night is uncomfortable. Indeed, many people may discontinue wearing the device during the night – removing it when they are asleep or the mask is dislodged during sleep.

 

Inspiratory Muscle Training 

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In our early studies, we showed that inspiratory muscle training (IMT) can increase respiratory muscle strength while improving sleep and lowering blood pressure. The reduction in blood pressure is greater than that gained from more traditional forms of aerobic exercise and in many cases, exceeds that obtained with blood pressure medication.

For the current clinical trial, we will implement inspiratory muscle training in a larger number of middle age and older, adults with above normal blood pressure and moderate-severe obstructive sleep apnea. Participant will train for a period of 24 weeks with follow ups 4 weeks and 8 weeks after the training program ends.  See the study timeline below. We will continue to recruit participants to the study through 2024 with the study close estimated in early 2025.  

 

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Interested participants will undergo initial screenings of cardiovascular, respiratory and sleep health. If eligible, participants will be randomly assigned to one of two groups as follows: 1) inspiratory muscle high resistance training that emphasizes gains in respiratory strength or 2) inspiratory muscle low resistance training that emphasizes gains in respiratory control. Subjects in both groups will perform their training at home completing 30 breaths per day, 5 days a week, for 24 weeks. All participants will be paid for their time and receive personalized training.

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If interested, click this link to complete our pre-screening questionnaire!