Sleep Through Her Eyes: Unpacking Gender Differences in Sleep and OSA

by Alison S. Kole, MD, MPH, FCCP, FAASM

 Sleep, a fundamental aspect of health and well-being,¹ exhibits unique characteristics and challenges in women, influenced by biological, hormonal, and life cycle factors. These distinctions not only shape sleep patterns but also affect the presentation and diagnosis of sleep disorders, including Obstructive Sleep Apnea (OSA). This article delves into the unique sleep characteristics in women and how OSA presents differently in females compared to males, shedding light on the necessity for tailored diagnostic and therapeutic approaches.

Hormonal Influence on Sleep

Gender differences in sleep quality correlate with the onset of puberty.² The female reproductive hormones, estrogen and progesterone, play crucial roles in regulating sleep. Their levels fluctuate throughout the menstrual cycle, pregnancy, and menopause, impacting sleep quality and patterns. For instance, during the luteal phase of the menstrual cycle, progesterone levels peak, increasing core body temperature at night, which contributes to more daytime sleepiness and more awakenings during the night.³ Similarly, during pregnancy, especially in the third trimester, sleep can be significantly disrupted due to hormonal changes, physical discomfort, restless legs (RLS), and anxiety.⁴

Sleep Disorders and Menopause

Menopause is a pivotal period in a woman’s life, marked by significant hormonal changes that can profoundly impact sleep. The decline in estrogen and progesterone levels lead to vasomotor symptoms (hot flashes) which can contribute to sleep disturbances, insomnia, increased sleep latency, and decreased sleep efficiency. Women may find an uptick in RLS symptoms, particularly if their transition leaves them with heavier periods and resultant loss of iron.⁵ The protective effect of these hormones on the upper airway muscle tone diminishes, leading to an increased likelihood of airway obstruction during sleep (OSA).⁶

Unique Presentation of OSA in Women

OSA in women often presents with symptoms that differ from the classic signs observed in men, across the lifespan. While loud snoring and prolonged apneas are hallmark symptoms in men, women may exhibit more subtle signs such as fatigue, insomnia, morning headaches, mood disturbances, and unrefreshing sleep. This difference in symptomatology can lead to underdiagnosis or misdiagnosis of OSA in women, as their symptoms might be attributed to stress, anxiety, or depression instead.⁷

Women diagnosed with OSA often present with what appears to be a less severe variant of the condition when evaluated using the Apnea-Hypopnea Index (AHI), a tool for assessing sleep apnea severity. Nonetheless, this perceived mildness does not imply a minimal effect on their overall health and well-being. In fact, women experience brief apneic incidents but face more intense drops in oxygen levels during these moments. They also show a reduced frequency of OSA when lying on their back and a concentration of apneic events during REM sleep phases.^8–10 Women, especially those in the premenopausal or perimenopausal stages, often exhibit a pattern of frequent increases in respiratory effort that end with brief awakenings. Unlike typical OSA, these do not involve as significant collapse of the airway, hypoventilation, or oxygen desaturations, a condition known as “upper airway resistance syndrome” (UARS).¹¹ These less obvious disturbances might not affect the Apnea-Hypopnea Index (AHI) scores, suggesting normal sleep. However, evaluating the Respiratory Disturbance Index (RDI) may offer a more comprehensive assessment of sleep disruption in women.

Diagnostic Challenges

The unique characteristics of sleep and OSA in women pose diagnostic challenges. For example, the Centers for Medicare and Medicaid Services (CMS) policy for local coverage determination (LCD) of  both oral appliances as well as Positive Airway Pressure (PAP) devices for treatment of OSA states: “The respiratory disturbance index (RDI) is defined as the average number of apneas plus hypopneas per hour of recording without the use of a positive airway pressure device. For purposes of this policy, respiratory effort related arousals (RERAs) are not included in the calculation of the RDI.”^12,13 There is an enormous potential to miss the diagnosis of OSA in women who tend to have more RERAs and a lower AHI. Since home sleep apnea testing (HSATs) are both more economical and more convenient, home testing has become the new norm for evaluating OSA. However, particularly with more mild disease, there is the potential to underestimate OSA severity.¹⁴ This is why the clinical presentation is so key in women. Do not stop at HSAT when there is a clinical suspicion. Crossfunctional collaboration between medical sleep specialist and dental sleep specialist is paramount to protecting the sleep health of women.

Gender-Specific Sleep Medicine

Recognizing and addressing the unique aspects of sleep in women are crucial steps towards personalized medicine. Healthcare providers should be aware of the gender differences in sleep disorders and consider these factors when diagnosing and treating female patients. Moreover, women should be encouraged to report sleep-related issues and seek professional help, emphasizing that sleep disturbances are not merely stress-related but could be indicative of a sleep disorder. Ladies, we do not need to be stoic about our sleep!

Conclusion

Sleep in women is influenced by a myriad of factors, including hormonal changes that can lead to unique sleep characteristics and distinct presentations of disorders such as OSA. Understanding these differences is essential for providing appropriate care and improving the overall health and well-being of women. As research continues to evolve, it is hoped that more gender-specific approaches in sleep medicine will emerge, offering more effective diagnosis and treatment options for sleep disorders in women.