When at rest, your body passes through five separate stages of sleep; the last one is known as REM (Rapid Eye Movement) sleep. This amounts to almost 25 percent of total sleep time, and it tends to dominate the hours before you wake up.
Unfortunately, people with sleep apnoea can be more likely to miss out on REM sleep. If you wake up during the night, the sleep cycle will be disturbed and you'll impair your ability to reach the final REM stage. Additionally, frequent waking can cut down on your sleeping time, meaning that you never quite reach that all important final part of your sleep cycle, during which REM sleep dominates.
This can be a real problem since a lack of REM sleep is associated with a number of serious mental and physical health issues.
Sleep apnoea often makes people more irritable, but a lack of REM sleep can also cause deeper emotional problems. One study compared two groups during sleep. They found that participants who had their REM sleep cycles interrupted were more likely to experience difficulties working through emotional distress.
Research has concluded that the body burns more calories during REM sleep than during any other stage, but it wasn't always known whether a lack of REM sleep actually had any impact on weight gain. However, one recent piece of research looked at the sleeping habits of normal-weight children compared to overweight children. They found a strong correlation between carrying excess weight and missing out on the final hour of sleep typically associated with the REM stage.
REM sleep has long been thought of as important for the formation of memories, and emerging research has made this seem even more likely. Studies have found that REM sleep is vital for the consolidation of memories; missing out on REM sleep is thought to inhibit your ability to retain memories. Even more significantly, problems associated with a lack of proper REM sleep have been implicated as one of the earliest indicators of dementia.
Though you might feel like you are sleeping enough each night, even with sleep apnoea, your constant waking could be preventing you from entering the crucial REM stage. If you think you have sleep apnoea, make sure you speak to your doctor as soon as possible to arrange sleep studies so you can get the help, and rest, you need.