REM Sleep Apnea: REM vs. Non-REM Breathing

When you fall asleep, your body embarks on a fascinating journey called the sleep cycle, repeating 4 to 6 times in 90 to 110-minute intervals. This cycle includes rapid eye movement (REM) sleep and non-REM (NREM) sleep stages.

There are 3 NREM sleep stages. The cycle begins with the light N1 stage, which lasts 1-7 minutes, with slower heartbeat and relaxed muscles. Deeper N2 lasts 10-25 minutes, lengthening later, marked by reduced body temperature, heart rate, and breathing. 

This is followed by restorative N3 deep sleep, which is approximately 20-40 minutes, characterized by minimal muscle activity and slow delta brain waves. Finally, REM sleep occurs, increasing in duration toward morning.

About 75% of your night is spent in NREM sleep – and the remainder in REM, during which breathing irregularities related to sleep apnea are more common. 

The transitions between lighter and deeper stages prepare your body and brain for the vivid dreams and unique challenges of REM sleep, especially for people who suffer from sleep apnea.

Normal Breathing in Sleep

During sleep, your breathing slows to 12-20 breaths per minute and becomes more regular and shallow. In NREM's deep N3 stage, breathing reaches its slowest and most stable pace, supporting bodily repair, and this is maintained in N2. 

REM sleep introduces irregular breathing patterns, with faster, shallower breaths and occasional pauses. For individuals with sleep apnea, these variations can be stark, as oxygen levels during REM sleep apnea tend to drop significantly, amplifying disturbances. This causes loud snoring, gasping for breath, and choking during sleep.

Sleep Apnea’s Effects on Breathing During Sleep

During REM sleep, the upper airway is prone to a temporary loss of muscle tone, leading to unstable breathing. It is a normal part of REM; however, in people with sleep apnea, the airway obstruction becomes more frequent and prolonged. 

During NREM sleep, airway obstruction is less likely in those with obstructive sleep apnea (OSA), as muscle activity is relatively stable. However, the severity of sleep apnea during NREM can still increase due to other factors, including a drop in respiratory pattern. 

Oxygen Saturation and Carbon Dioxide Levels

Oxygen levels drop more significantly during REM sleep apnea compared to NREM. Oxygen saturation levels often fall below 90% and even more as AHI increases. This becomes more pronounced in REM-related OSA, where low muscle tone reduces oxygen levels further, causing greater sleep disturbances and health complications. 

NREM AHI events result in milder carbon dioxide (CO2) rises and quicker recoveries. However, in severe cases, oxygen levels still fall significantly. This causes next day sleep apnea symptoms, such as heightened daytime sleepiness and fatigue.

Effects on Sleep Apnea Management

CPAP Therapy

Continuous positive airway pressure (CPAP) therapy is the most common treatment option for OSA. It is designed to prevent airway collapse, improve oxygen levels and promote better sleep in patients with sleep apnea. 

The effects of CPAP therapy can vary significantly during different sleep stages. CPAP increases deep N3 sleep, reduces arousals, and shortens the time it takes to reach REM stage. 

CPAP devices must frequently adjust pressures during these stages. 

Lifestyle and Medication 

Managing REM sleep apnea and obstructive sleep apnea requires a tailored approach. Positional therapy, weight loss, and better sleep habits can produce varying results depending on the sleep stage. 

REM-predominant sleep apnea often worsens when sleeping on your back. In this case, positional devices that minimize back-sleeping may help reduce apneas and promote better quality sleep. However, this treatment is less effective during REM sleep due to muscle changes in the airway. 

If left untreated, REM-related sleep apnea can lead to daytime dysfunction as well as other health complications. Therefore, it is essential to make additional adjustments in lifestyle.

Avoiding alcohol and sedatives is important, as these can impair upper airway muscle tone, further complicating REM sleep disturbances related to sleep apnea. 

Treatments for nasal obstruction and oral appliances may be suitable for people with REM OSA who struggle with CPAP therapy. However, evidence supporting these alternatives remains mixed. 

Talk to Your Healthcare Provider

Understanding the differences between REM sleep apnea and non-REM sleep breathing is essential for your health and successful treatment. REM-related sleep apnea presents unique challenges due to muscle atonia and reduced blood oxygen levels, the severity of which varies significantly across sleep stages.

Your healthcare provider will develop an individually tailored treatment and management strategy. This will consist of CPAP therapy and lifestyle changes, which address obstructive sleep apnea comprehensively. 

Early intervention helps achieve better treatment outcomes and reduces the risk of health complications such as cardiovascular disease and cognitive impairment. If you are suffering from sleep apnea or notice symptoms of sleep apnea, seek professional evaluation today. 

Your healthcare provider can identify your sleep apnea type and stage-specific severity, enabling personalized care that restores restorative sleep and safeguards your long-term health and wellbeing.