How the Distribution and Importance of Different Types of Sleep Throughout Our Lives Diverges From Birth to Old Age
The Importance and Abundance of REM Sleep For Fetuses and Newborns
The Distribution of the Different Types of Sleep of a Fetus
Throughout our life the amount of time we sleep as well as the ratio between NREM and REM sleep varies significantly. Before they are born, babies in the womb sleep twenty-four-seven. This includes a total of six hours of NREM sleep, six hours of REM sleep and twelve hours in an intermediary sleep state. Only in the final trimester around two to three hours of each day are spent awake in the womb. At this point of the pregnancy the amount of time spent in REM sleep progressively increases.
The Importance of REM Sleep For a Fetus
In the last two weeks of pregnancy the fetus will spend around 9 hours a day in REM sleep. In the last week before birth this increases to a lifetime high of 12 hours of REM sleep a day. This is because REM sleep is vital for promoting brain development. REM sleep infuses the brain of a fetus with a large number of neural connections or synapses. In other words, REM sleep builds the neuro-architecture of the brain of a fetus. It is during the few weeks before and after being born that the brain is undergoing the greatest construction.
Why it is Crucial Not to Disrupt a Developing Fetus or Newborn’s REM Sleep
It is very important not to disturb or impair the REM sleep of a developing infant brain as there can be severe consequences. This can create irreversible damage by hindering brain development, leading to an adult who is socially abnormal. This is likely the cause of several developmental conditions such as autism.
Why Alcohol Should Be Avoided At All Cost While Pregnant or Breastfeeding
One of the most common culprits for disturbing the brain development of a developing fetus or newborn is alcohol. This is because alcohol is one of the most powerful suppressors of REM sleep. More information on the negative effects of alcohol on sleep can be found on the page focused on The External Causes of Insomnia.
Research indicates that drinking alcohol during pregnancy (even only one or two glasses of wine) results into a significant decrease in the amount of time unborn babies spend in REM sleep. Additionally, this reduces the intensity of REM sleep experienced by the fetus. Furthermore, alcohol causes unborn infants to suffer a drastic decline in breathing during REM sleep. Moreover, studies indicate that breathing rates drop from a normal 381 per hour to just 4 per hour. Similarly, while breastfeeding it is highly recommended not to drink any alcohol. This is because alcohol is easily absorbed in the mother’s milk. This leads to more fragmented sleep of the baby and a total of 20 to 30 percent suppression of REM sleep.
The Rapidly Changing Sleep Patterns of Young Children
Up until the first year of a baby’s life their sleep schedule is largely chaotic. This is because of their polyphasic sleep pattern resulting into numerous short snippets of sleep throughout day and night. The reason is because the ‘suprachiasmatic nucleus’ which is the twenty-four-hour clock that controls the circadian rhythm takes considerable time to develop. By the one-year milestone of development the child now spends more of the day awake, with regular naps, and more of the night asleep. At four years of age the child transitions to a biphasic sleep pattern with a long bout of sleep during nighttime and a single daytime nap during the day.
The Importance of Deep NREM Sleep For Teenagers
The older the child becomes the less time will be spent sleeping and the amount of REM sleep will decrease. The balance of NREM/REM sleep will stabilize at around 80/20 by the late teen years and will remain the same throughout early and mid-adulthood.
The Main Reason Why Teenagers Often Act Irrational and Impulsive
During adolescence, teenagers are often considered as irrational and impulsive. This is because the frontal lobe, which is the part of the brain responsible for rational thinking and critical decision making, is the last part of the brain to be fully developed. This development is done through the maturation process of deep NREM sleep.
The Importance of Deep NREM Sleep For the Mental Health of Teenagers
Plenty of deep NREM sleep is especially important for teenagers and children for a healthy development of their brain. Various psychiatric disorders such as schizophrenia, bipolar disorder, major depression and ADHD are considered disorders of abnormal development. This is because they often emerge during childhood and adolescence. Studies indicate a potential connection of some of these psychiatric illnesses (such as schizophrenia) with a lack of deep NREM sleep in young individuals.
The Biological Shift Forward of the Internal Clock of Teenagers
Adolescents experience a significant change in their circadian rhythm. This is because their internal clock is shifted forward progressively during puberty compared to their younger siblings. The biological forward move of the internal clock is common across all adolescents, regardless of culture and geography. It even surpasses the circadian timing of their adult parents.
This shift forward of the circadian rhythm of adolescents serves as an ingenious biological mechanism. This allows teenagers to operate independently for several hours each day, as a peer-group collective. This prepares them for the approaching separation from their parents. It is only between 12 am and 1 am that the circadian rhythm of a teenage brain starts to shut down alertness and allows for sleep to commence.
The Ignorance of Present-Day Society and Parents Regarding the Biological Sleep Requirements of Teenagers
Unfortunately, the present-day society is not well designed to appreciate the fact that teenagers need more sleep than adults and are biologically wired to obtain that sleep at a slightly different time. This results in a lot of frustration from parents and often leads to sleep deprivation of teenagers. Parents around the globe would be wise to accept and embrace this biological sleep requirement. They should accommodate sufficient sleep of their children to prevent the suffering of developmental brain abnormalities and increased risk of mental illness. Once these teenagers grow into adulthood their circadian schedule will gradually slide back in time to an earlier schedule.
Sleep in Old Age and the Decline of Deep NREM Sleep of Seniors
The Decline of NREM Sleep of the Elderly Population
The saying that older adults need less sleep is a myth. Older adults need as much sleep as they do in midlife but are simply unable to generate the same amount of sleep. This is often the result of some medical conditions and/or certain medications more commonly taken by older adults.
While the amount of REM sleep remains largely stable throughout our adult life, the amount of deep NREM sleep does not. The older we become, the less hours of deep NREM sleep we are able to obtain. Furthermore, the intensity and quality of those deep NREM brainwaves are reduced significantly. By the time we reach seventy years old, we will have lost 80 to 90 percent of the deep NREM sleep we were enjoying as a young adult.
Why Elderly People’s NREM Sleep is Degraded
The main reason why elderly people are unable to maintain the same amount of deep NREM sleep compared to younger adults is largely because of a process called atrophy. Atrophy is the structural deterioration of the brain caused by the aging process. Research illustrates that certain parts of the brain are much more affected than others. It appears that the part of the brain responsible for generating deep sleep (the mid frontal region of the brain) is targeted first and suffers the most dramatic deterioration as we age.
Deep sleep is very important for cementing new memories and retaining new facts. This is the reason why so many elderly people have severe issues with forgetfulness and remembering information such as people’s names and upcoming hospital appointments. Studies indicate that sleep deprivation and insomnia are very common issues in the elderly population. More information on this topic can be found on the page focused on Insomnia of the Elderly.
The Decline of Sleep Efficiency of Seniors
The sleep efficiency of elderly people drops to around 70 or 80 percent. This means that within an eight-hour period in bed, about one to one and a half hours is spend awake. This is due to sleep fragmentation as older people wake up more frequently throughout the night. The main causes of the reduction of sleep efficiency include medications, the effects of diseases, and more often than not, a weakened bladder. This causes them to visit the bathroom more frequently at night.
The Health Risks of Nighttime Bathroom Visits of the Elderly
The nighttime bathroom visits of the elderly pose an additional high risk of falls and fractures. These falls occur mostly because of grogginess, lack of vision and light headedness. This is because many older adults lack control of blood pressure. It is therefore important for elderly people to make the necessary precautions to avoid falling and breaking bones at night. This is because they markedly increase morbidity and hasten the end of life of an older adult.
Tips and Recommendation For the Elderly to Avoid Falling At Night
Some tips for safe sleep for the elderly include having one or more dimmed or motion activated night-lights in the bathroom and hallway. Additionally, it is recommended having an easily reachable nightstand lamp to illuminate the path towards the bathroom. Furthermore, it would be wise to remove all potential obstacles on the path to the bathroom. Moreover, it is important to always keep a telephone by the bed with emergency phone numbers programmed on speed dial. Another obvious precaution is not to drink too much water in the hours before going to bed.