Learn how children and adults sleep, how we slept in the past, and how our sleep patterns change over lifetime.
Although it sounds like an over-generalization, the older you get, the less you sleep. This is especially the truth from birth to age 25, and for elderly people who sleep shallower. In this article, learn how children and adults sleep and how our sleep patterns change over lifetime.
You sleep the most when you are a baby. Newborns sleep 16 to 18 hours a day, and half of their sleep time is spent in REM sleep, while the other half is spent in deep (slow wave) sleep. Very little time is spent in light sleep, also known as the first and second sleep stage. Once babies reach age one, they will sleep 13 to 14 hours a day. Their sleep time will decrease as they reach adolescence.
As the child grows, the time spent in REM sleep decreases until it reaches about 90 minutes per night. Ninety minutes per night is typically reached in the mid-teens. This is also the time when stage 2 sleep increases. Deep sleep also known as slow wave sleep is vital for children’s growth and development. It’s very hard to awaken anyone from deep sleep, but kids especially.
Teenagers at least 8 to 10 hours of sleep per day. Unfortunately, due to school and social pressure, as well as an abundance of extracurricular activities, teens rarely have enough time to sleep. What makes snoozing for them even harder is the fact that this is the age when their internal biological clocks shift and tend to keep them awake later in the evening and make it difficult for them to wake up early in the morning. Simply explained, teens are natural night owls. Some studies have found that moving school time just half an hour later would help improve teens’ performance in school.
Late teens in their early 20s are considered to be young adults. Young adults have the lowest rate of struggling with a sleep disorder except for babies. They are past common childhood disorders such as night terrors and somnambulism but are also too young to experience insomnia or fragmented sleep typical for older adults. We can say that young adulthood is the golden age of sleep.
Once you reach your mid-twenties, you won’t struggle with a circadian rhythm shift as you did in your teenage years. By the mid-20s the shift in our internal body clocks subsides, and your chronotype will be definitely established. You might stay a night owl or simply become an early bird. As an adult, you need around 7 to 8 hours of sleep to function well. Although many people claim they require less or function well on less sleep, studies have shown that only 10% require more or less sleep than the recommended amount.
Studies conducted on different population groups by sex, race, marital status, socioeconomic status, etc. show that age is one of the most significant demographic factor when it comes to sleep disorders and changes in sleep patterns. For women, pregnancy and menopause cause significant changes in sleep patterns. For example, in the first trimester of pregnancy, expecting mothers require more sleep than usual, and some experience insomnia due to hormone changes. Later in pregnancy, some mothers-to-be experience snoring or restless legs syndrome (RLS) but these issues disappear as soon as the baby is born. Hormonal changes may severely affect sleep during menopause. During these years, problems such as snoring, insomnia and sleep apnea are more common. Apart from hormonal imbalance, psychological factors associated with menopause may also disturb sleep.
Many people believe that sleep needs decline as we age. However, this is not the truth. Unfortunately, elderly people do have more struggles with sleep, and frequently experience insomnia, delayed sleep/wake phase disorder or advanced sleep/wake phase disorder, but that doesn’t mean they need less sleep. On the contrary, they need about the same amount of sleep that they needed in early adulthood – seven to eight hours a night. Once we reach age 40, the number of nocturnal awakenings starts to increase. Older people have an increased need to nap during the day and make up for the lost sleep caused by fragmentation at night. Retired people often have a greater need to nap that working people do.
When it comes to insomnia in older people, studies have shown that people sleep shorter as they age. The scientists focused on examining both the S and the C process – homeostatic process for sleep regulation and the circadian process and found out that both processes decline over time. Homeostatic process declines earlier than the circadian one.
Stereotypes such as lazy teens who sleep all morning and grandparents who wake up before dawn and are in bed very early in the evening are heavily grounded in reality. The mentioned sleep patterns have nothing to do with someone’s lifestyle choices, but more with their biology. Scientists have found that the expression of some genes associated with the circadian cycle change with age. A study published in the Proceedings of the National Academy of Sciences has found out that a specific internal body clock starts ticking only in the brains of older people. So far, researchers have found over 230 genes that control circadian rhythms in the prefrontal cortex. When one reaches old age, some of these genes simply shift off or stop expressing actively. Instead of them, other genes start expressing and form a new circadian clock – forcing the affected person to become active earlier in the day than usual.
It’s also an interesting fact that poor people sleep worse than rich people, and that women sleep worse than men. However, in both cases, the correlations were weak. From a public health perspective, transitions from young adult to middle age and from middle age to old age are the most significant inflection points and periods when we should be careful the most.
Communal sleep is actually more common in less developed societies than in the technologically advanced ones like the ones in the West. Studies have not yet indicated whether this is a cultural preference, a choice, or simply a consequence of having less space to sleep in.
An anthropologist Carol Worthman conducted research on primitive cultures and their sleep practices. She believes that the customs of primitive tribes such as surviving hunter-gatherer societies indicate how all humans slept in the past. She believes, for them, sleep was a very fluid state, and that is could happen whenever the individual felt sleepy. Nighttime sleep was a social activity – pretty different from the isolated environments most modern people snooze in today.
If this is true, people in the past didn’t sleep in one isolated block for seven to eight hours a day. Our sleep was rather polyphasic. It’s very hard to determine an ideal sleep pattern. Sleep experts advise individuals to follow a regimen that works best for their biological needs and lifestyle demands.
The first thing that comes across our minds when you hear tribal sleep is probably sleeping together or every something that involves sleeping and waking up at the same time. However, this isn’t how slumber played out in big groups. Sleep patterns weren’t synchronized because some members of the tribe always have to be on the lookout and protect the tribe from potential threats. However, it is true that in social sleeping, some individuals affected the sleeping patterns of other individuals. In primitive living arrangements, it’s much easier to notice that sleep can be a social activity. The modern pattern or sleeping alone or only with one partner was rare in the past.
Historically, people slept with their kids, parents, siblings, neighbors, and so on. Babies and toddlers typically slept with their mothers. In primitive cultures, infants never sleep separately from their mothers, and according to one anthropologist, this separation contributes to the risk of SIDS (sudden infant death syndrome). According to some studies, when babies slept in separate rooms from their parents, SIDS incidents increased. One explanation for this is that when the baby is cradled with the mother, the mother sleeps shallower and may react to subtle changes in their baby such as breathing problems. Nighttime feedings are also a lot easier when parents don’t have to get out of bed.
Did you know that sleep is also tied with the supernatural, mysticism and the divine? Forced sleep deprivation (which often leads to vivid hallucinations) can be employed in religious ceremonies. For example, the ancient Egyptians were obsessed with death and spent a lot of their religious energy on sleep. Due to their elaborate hairstyles (typically worn by the upper class), they needed to create a special headrest to protect their hair during sleep. When a teen got a headrest, that was a symbol of transitioning from youth to adulthood. The headrests were also practical for keeping bugs off the head and allowed decent cooling in a pretty hot climate. The Egyptians also thought snoozing was a time when they could communicate with the dead.
So, you may be wondering if we slept so differently in the past, why did we give up the ancient practices. Did our sleep evolve? How are our sleep needs different from the ones in the past? Two historians, Craig Koslofsky and Roger Ekirch, were wondering the exact same thing. They mention that in the past, people were mostly bi-phasic sleepers and that a decline in bimodal sleep was noticed in Europe in the 17th century. Due to electrification and modern way of life that involved working 8 hours a day, people embraced monophasic sleep pattern. Ekirch has spent many years researching the history of sleep and found hundreds of literary references that mention first and second sleep. Historians believe that people went to sleep in the evening, woke up around midnight, stayed awake for around 2 hours and then went to sleep again. The time between first and second slumber was spent socializing, praying, working and similar.
Electrification and later the development of electronic devices has multiple times been identified as one of modern society’s sleep problems. However, the problem with artificial light is not so much in the fact that it mimics the sun and has the ability to disrupt our circadian rhythms, as much as it is in the fact that artificial light encourages people to work, socialize and similar over a greater period of the day, or simply decide to start their day very early or go to bed late. The real problem is that we now have the ability to push our sleep time to a smaller window. Due to our hectic schedules and pressures that come with the modern way of life, we often don’t have enough time to sleep and end up being sleep deprived and with a major sleep debt.
Due to our sleeping habits in the past, some people and even experts believe that sleep maintenance insomnia is not a defect, but simply a throwback on one of our natural sleep patterns – bimodal sleep. However, it is important to mention that sleep maintenance insomnia is a real problem and manifests differently. Occasionally waking up in the middle of the night and being unable to sleep in one consistent block is normal, especially if you still feel restful and refreshed in the morning. However, experiencing multiple awakenings during the night, waking up tired and groggy, and struggling with daytime sleepiness indicates you have a sleep disorder.
Nowadays, most people sleep in a single consolidated block of about eight hours during the night. However, this still doesn’t mean this is the only sleep pattern we embrace. In a way, many of us still practice bimodal sleep in the form of daytime naps. Daytime naps are a perfect way to replenish energy and restore our alertness.
In many cultures, particularly those in tropical regions, afternoon napping is very common and has become a part of one’s daily routine. The exact timing of the naps is not scheduled, but it’s kind of mandatory. It’s very interesting to mention that some stores or even government offices stop for an hour or two every afternoon.
Afternoon naps are typically short and are very beneficial for quickly replenishing our energy and alertness. By napping, we can decrease our sleep pressure a bit. Our sleep pressure or sleep drive increase through the day, as we spent energy and sleep-inducing chemical adenosine builds up in our body. According to studies, napping typically happens during the warmest period of the day and generally follows a large mid-day meal.
For most people, naps last from 30 to 60 minutes. Ideally, a nap shouldn’t last longer than 20 minutes. Any longer, you are increasing the risk of falling into deep sleep and have a very difficult time waking up. After a nap, you should feel refreshed and alert. Taking proper naps can help you stay awake and alert in the late afternoon and evening, and even sleep better at night. On the other hand, napping for too long can cause insomnia in the evening.
According to sleep experts, napping can be a good way for people who don’t sleep well at night to catch up a bit and restore their sleep debt. They do caution, however, that people with insomnia may make their nighttime sleep issues worse by sleeping during the day.