Sleep Apnea and Normal Sleep
Normal sleep changes with age. Sleep disorders symptoms like sleep apnea can be observed between infants, children and teenagers, and between adults and the elderly. What correspond to “normal changes” in sleep pattern with age?
Sleep Apnea in adults and the elderly
For adults, normal sleep is generally restful. Adults sleep 7-8 hours, with a relatively short sleep onset and seldom awakenings in the night. An adult’s sleep architecture presents all the normal components: preponderance of deep sleep at the beginning of the night and REM sleep in the latter part of the night. However, difficulties can sometimes occur, resulting in non-restful sleep: long sleep latency, with frequent awakenings. Multiple factors can contribute to a “poor sleep” such as lifestyle (shift work), poor sleep habits (going to bed too early) and medical illness (obstructive sleep apnea, arthritis, depression, etc.).
Elderly people often have less nighttime sleep (six hours on average), daytime naps not included. Sleep becomes lighter in favour of reduced deep sleep (non-REM sleep), without much change in the REM sleep. The elderly have more frequent and longer awakenings during the night than younger people. Contrary to teenagers, the elderly go to bed earlier and get up earlier. These differences are attributable to discrepancies between their biological clock (located in the brain) and the sleep-wake cycle.
Infants, Children and Teenagers
On average, infants sleep 16-18 hours a day. Their sleep-wake cycle is approximately 3-4 hours per 24-hour period. An infant’s sleep consists of quiet sleep (precursor to non-REM sleep, Stages 1, 2, 3) and active sleep (precursor to REM sleep). Starting at the age of three months, the infant’s sleep can be subdivided into light, deep and REM sleep, quite similar to the sleep architecture observed in adults. However, the length of a sleep cycle (light, deep and REM sleep) differs between infants and adults: infants 3-9 months old will have an average of a dozen sleep cycles, whereas adults have approximately five or six. Children under age six sleep an average of 10-12 hours, without a nap in the daytime.
Teenagers sleep an average of nine hours per night. Moreover, they will tend to go to bed later at night, and wake up later. Often, teenagers present with delayed sleep phase syndrome (DSPS), which is conditioned by social factors and greatly compromises their physical and psychological health.
At what age would these changes in sleep occur?Is there a critical age at which these changes in sleep would occur? According to one of the most important American longitudinal studies, the Sleep Heart Health Study, sleep would change as early as the age of 30 and not 60, contrary to what was believed before. For example, deep sleep (non-REM sleep, Stage 3) would decrease around the age of 40, particularly for middle aged men and men and women over 70 years old.
And, daytime napping?
Apart from young children, naps are generally recommended for adults who have no trouble falling asleep or staying asleep, or even in some cases of narcolepsy. Daytime napping may interfere with the nighttime sleep. Ideally, daytime naps at home or work (for people doing shift work) should range between 10 and 20 minutes. Accordingly, the naps will be short enough to not interfere with the nighttime sleep or with how alert you are at work. If you feel tired or drowsy during the day, despite a sufficient amount of sleep, consult your doctor.