Deep sleep is one of the four stages of non-REM (non-dreaming) sleep. At this stage, body temperature drops while heart rate and breathing become steadier, rolling eye movements vanish, and large slow brain waves known as delta waves begin to appear on EEGs.
As we age, people often spend less time in this stage of sleep; however, this doesn’t necessarily point towards any sort of sleeping disorder.
Stage 1
From babies and young children onward, we’re taught about the importance of getting enough restful sleep. Babies and toddlers are encouraged to go to bed early and rise early for optimal rest; adults are warned about its impact on cardiovascular disease and other serious health issues caused by lack of restful rest.
Sleep requirements remain consistent throughout life, though changes to our sleeping patterns often become apparent as we get older. Sleep difficulties may arise during middle adulthood due to weight gain, medication side effects or the onset of medical conditions like heart disease and diabetes; shifting hormone levels (particularly growth hormone) also reduce deep restorative sleep.
As people enter late adulthood, their delta wave density gradually declines and they become lighter sleepers despite maintaining good health; this does not indicate any sleep disorder; in fact earlier wakings and more daytime naps may even become common at this age.
Studies have also demonstrated that men experience a lower rate of decline in slow wave sleep than women, possibly as women experience more difficulties sleeping during perimenopause and menopause, such as increased wakefulness and disturbances to deep sleep patterns. Overall though, most people do experience reduced total sleep time as they age as well as deep sleep levels decreasing; this does not necessarily represent any cause for alarm and should be considered alongside other aspects of lifestyle and well-being when making assessments of lifestyle and wellbeing.
Stage 2
Transition from adolescence to middle adulthood is marked by a decline in deep slow wave sleep that is only partially offset by an increase in light non-REM (stages 1 and 2) sleep. Furthermore, total sleep time decreases and both nocturnal awakenings and fragmentation increase; all seemingly attributable to normal physiological alterations of the circadian system and homeostatic processes without medical comorbidities or medication use being involved.
Middle age changes do not always indicate that someone has a sleep disorder; however, if a senior complains that they are waking frequently during the night or do not feel refreshed when waking up, you may wish to consult their physician and discuss this matter further.
Stage 3, or deep sleep, occurs when breathing and heart rate become steady and body temperature becomes less fluctuant. Brain waves reach their lowest activity level during this phase; you are less likely to dream at this time. Deep sleep is necessary before entering the more active REM sleep stage.
Gender can play an influential role in how much deep sleep one gets; women tend to experience greater amounts of the slower, deeper stages than men during menopause and the perimenopausal period; however, both genders experience decreased amounts of deep sleep after age 70.
Stage 3
By early adulthood, most people begin spending less time sleeping deeply; although they still may get their recommended 7-8 hours, they may not wake up feeling quite as refreshed.
This decrease in deep sleep is likely caused by a gradual tapering off of slow wave sleep (stage 3 sleep). This could be the result of several factors including the hormonal shifts of puberty, growth hormone decline in young and middle adulthood and chronic pain affecting sleep patterns.
Your body spends more time in the early phases of non-REM sleep and less in REM, where dreams typically form, causing you to experience more nocturnal awakenings, or sleep disturbances that make you wake up during the night. This may result in increased numbers of awakenings during this phase.
By the end of middle adulthood, most people have generally adjusted to these changes and no longer complain as much about sleeping issues – likely because they recognize them as normal parts of aging as well as realizing the many health benefits provided by adequate rest. Unfortunately, they may also have medical comorbidities and medications which further disrupt sleep which makes achieving quality rest a challenge.
Stage 4
Lifelong we have heard the importance of sleep to our health, from its impact on mood to managing metabolisms and helping prevent chronic diseases. Studies have even linked it with changes in behavior such as decreased anxiety.
Babies and children typically benefit from healthy levels of slow wave sleep, which helps strengthen neural networks, blood cells, muscles, and other essential physiogical components during development. Teens entering puberty experience a decrease in this stage of restful slumber; however, once adulthood arrives this stage doesn’t decrease as rapidly allowing adults to transition away from more consolidated episodes toward lighter non-REM stages of non-REM sleep with shorter wakefulness episodes.
As we enter middle adulthood, weight gain, medications, and health conditions can have an adverse impact on sleep quality. People may become tired earlier during the day which results in taking more naps; also deep sleep levels can decline leading to frequent awakenings and less restful nights for some individuals.
Sleep needs vary across adult life; however, certain factors can impede an adult’s ability to get restful rest. If you notice that someone close to you is experiencing difficulty sleeping, it’s essential that they consult their physician who will conduct a comprehensive health history and medication review as well as conduct an in-person physical exam.
