SNORING AND THE STAGES OF SLEEP
To achieve a better understanding on the problem of snoring, it is also crucial to understand the structure of sleep. You may have observed that some people tend to snore differently from others. In some parts of the night's sleep, snoring also becomes louder and more disturbing than others. These differences can be explained with a deeper look into how we sleep. There are two distinct stages of sleep: the rapid eye movement (REM) stage and the non-rapid eye movement (NREM) stage. The stages are named as they are due to the rapid eye movement that is a distinguishing characteristic of one and is not present in the other. However, there are more to these two stages than the presence or absence of the movement of the eye.
The NREM state is further classified into four stages where the response to external stimuli progressively decreases. These four stages create the continuum from heightened wakefulness to deep slumber. The first stage connects the disparity between definitive wakefulness and definitive sleep. The second stage is considered a light sleep since a person can easily awaken to any external stimulus. The transition between the second stage's light sleep and the upcoming deep sleep in stage four is observed in the third stage. The deepest slumber takes place in the fourth stage. During the fourth stage, it would be very much difficult to wake up a person. If a person awakens from the fourth stage, he or she is most likely to end up disoriented for a few seconds or minutes. The patterns of electrical activity in the brain encounter changes during these stages.
For the REM state, the brain works similarly to wakefulness. This state is characterized by shallow, mixed, and high frequency waves in the brain. Compared to stage 2, it takes more time to awaken to environmental cues but lesser time compared to the third and fourth stages. We usually awaken from this state, knowing that we dreamt of something while sleeping. Since sleeping occurs during this state, it is also referred to as the 'dreaming state'.
Other physiological differences between the two states also include the muscle tone. In REM sleep, there is no muscle tone due to the effective paralysis of skeletal muscles. Aside from that, changes in respiration will also be observed because of the airway's resistance to the air coming in.
Snoring associated with apnea is more likely to take place in the deep sleep stages (third and fourth stages) and in the REM state of sleep. Conventional snores, or simple snoring by almost everyone, are most likely to occur in any of the four stages, but not in REM sleep. Certainly, external factors that may cause snoring may also lead to problems in respiration, sleep structure and the interaction of the two.