Exercise as a treatment for sleep apnea

Citation:

Lee-Iannotti JK, Parish JM. Exercise as a treatment for sleep apnea. J Clin Sleep Med. 2020;16(7):1005–1006.

Obstructive sleep apnea (OSA) is associated with significant adverse consequences for those who experience it, but sleep specialists still struggle with identifying the optimal treatment for each patient. Although positive airway pressure (PAP) therapy is almost always effective when it is used, some patients do not use it or use it for only a small portion of the night.¹ Although oral appliances can be effective in some patients, they are not always effective and may have significant adverse effects, including temporomandibular discomfort.² Surgical options can be helpful in well-selected patients but also have many limitations. While there has been enthusiasm for the implantation of hypoglossal nerve–stimulation devices, these devices are not always effective, are costly and invasive, and require frequent follow-up visits.³ Other suggested alternatives include myofunctional therapy, which involves training oropharyngeal muscles, but the benefit in individuals even with mild OSA is uncertain.⁴ Weight reduction improves OSA most likely by the mechanism of reducing airway fat deposition in the tongue and the oropharynx, which increases cross-sectional airway diameter. However, significant sustained weight loss is difficult for most individuals.

Recent studies have shown that not all cases of OSA have the same probability of adverse consequences. For example, mild OSA (apnea-hypopnea index [AHI] 5–15 events/h) does not seem to be associated with excessive daytime sleepiness, hypertension, and other cardiovascular consequences as frequently as more severe OSA.^5,6 And OSA without a complaint of sleepiness does not seem to be associated with the same adverse consequences as cases of OSA that are associated with sleepiness.^7,8 Several phenotypes of OSA have been identified that have different clinical profiles.^9,10 Treating individuals with mild OSA with no or minimal symptoms with PAP presents both clinician and patient with difficult choices. PAP therapy seems to work best at improving symptoms of sleepiness and quality of life in individuals with more symptoms but may provide little to no benefit to those with minimal symptoms. It has been challenging to demonstrate improved cardiovascular outcomes in individuals with OSA.^11–13 Optimal treatment of asymptomatic individuals with mild or moderate OSA remains a difficult clinical quandary.

Each of the current treatments of OSA are aimed at directly improving upper airway dynamics in some way, by preventing airway collapse by positive airway pressure, mandibular advancement, or advancing the genioglossus muscle during sleep. In contrast, several recent investigators have made the interesting observation that aerobic exercise even in the absence of weight reduction decreases the AHI to a significant degree. Several randomized controlled studies on the relationship of OSA and aerobic exercise^14–17 have demonstrated physical exercise improves AHI without necessarily a change in body mass index. A recent meta-analysis of 8 studies showed improvement in aerobic exercise in quality of life, daytime sleepiness, and sleep quality, in addition to reducing the AHI.¹⁸

In the current issue of the Journal of Clinical Sleep Medicine, Hall et al¹⁹ have reported data showing the impact of aerobic exercise on sleep-disordered breathing on 155,448 individuals as part of the extensive Ontario Health Study. This large population–based study examined a variety of health-related behavior, medical history, demographic factors, and health service utilization. In this investigation, exercise behavior and physician-diagnosed OSA were examined. These investigators found that physical exercise was associated with a decreased prevalence of OSA independent of generally known risk factors for OSA including body mass index. Increased total physical activity, vigorous-intensity activity, and walking were all associated with a decreased prevalence of OSA. The limitations of the study were that the diagnosis of OSA was based on patient recall rather than on any objective testing, and therefore the control group may contain cases of undiagnosed OSA. The study does not include information on severity of OSA or on treatment. In addition, the amount of exercise and intensity were also based on patient recall, leading to potential recall bias. Nevertheless, despite these limitations, the methodology is very strong and the amount of data is large, providing robust findings that are very credible. This is the largest study so far reporting primary data on this topic. Individuals with OSA were also more sedentary than those without OSA.

The mechanism of this association is also unclear since it does not involve a direct physiological relationship of the upper airway. It is possible that aerobic exercise has an effect on genioglossus or pharyngeal dilator muscle tone, but this remains an area for future investigation. Exercise may affect fluid volume in the neck area.²⁰ Nevertheless, from a clinical basis, this relationship provides another option in the toolbox of recommendations for patients with mild OSA or mild to moderate OSA without symptoms since it does not require a prescription for an expensive and potentially uncomfortable device and is totally under the control of the patient. This observation also provides an avenue for future research into the relationship of exercise to upper airway anatomy and dynamics. Future investigations could also identify which patients are most likely to benefit from an exercise recommendation, how much and what type of exercise is optimal to achieve a reduction in the AHI, and the interaction of exercise and weight loss at improving symptoms of OSA. The study by Hall et al is a valuable addition to the literature on this interesting aspect of OSA.

DISCLOSURE STATEMENT

The authors report no conflicts of interest.