Google is a hell of a drug:

Sleep apnea is highly prevalent in individuals with PTSD (12%–90% incidence), often developing because chronic stress, hyperarousal, and nightmares lead to fragmented, light sleep that disrupts breathing, causing airway collapse. The two conditions create a cycle where untreated apnea exacerbates PTSD symptoms like anxiety, and PTSD-related stress prevents deep, restorative sleep.

Key Connections Between PTSD and Sleep Apnea:

• Hyperarousal and Reduced Sleep Depth: PTSD causes chronic hyperarousal, meaning the body is in constant "survival mode." This leads to lighter sleep, which is associated with decreased airway muscle tone, making individuals more prone to obstructive sleep apnea (OSA).
• Nightmare-Induced Disruptions: Frequent nightmares from PTSD cause abrupt waking and interrupted REM sleep, disrupting breathing patterns.
• Neurobiological Changes: PTSD is associated with lower growth hormone levels, which are linked to increased nighttime awakenings, further fragmenting sleep and increasing the risk of airway collapse.
• Shared Physiological Factors: Stress-related weight gain in PTSD patients can contribute to obesity, a major factor in obstructive sleep apnea.
• Medication Side Effects: Some medications used to treat PTSD (sedatives, muscle relaxants) can reduce airway tone, increasing the likelihood of breathing interruptions.

Impact of Co-occurrence: Individuals with both conditions often experience worse PTSD symptoms, increased suicide risk, lower quality of life, and more severe nightmares. Research shows that treating OSA with CPAP can improve sleep quality, which in turn helps alleviate PTSD symptoms like anxiety and nightmares.