Many of us see sleep as the natural ‘ consequence’ of our daily activities, and we may not be far from the truth.
However, experts say sleep serves a lot more purposes in our general well-being than we might imagine.
According to specialists at online portal Healthline, sleep is essential for good health. In fact, we need sleep to survive — just like we need food and water. So, it’s no wonder we spend about one-third of our lives sleeping.
The following are some of the scientific reasons why we need regular, sound sleep on a daily basis.
Many biological processes happen during sleep. These include:
- The brain stores new information and gets rid of toxic waste.
- Nerve cells communicate and reorganize, which supports healthy brain function.
- The body repairs cells, restores energy, and releases molecules like hormones and proteins.
According to scientists, these processes are critical for our overall health. Without them, our bodies can’t function correctly.
Sleep researchers say a lot is still unknown about the purpose of sleep. However, it’s widely accepted that there isn’t just one explanation for why we need to sleep. It’s likely necessary for many biological reasons.
To date, scientists have found that sleep helps the body in several ways. The most prominent theories and reasons are outlined below.
Energy conservation
According to the energy conservation theory, we need sleep to conserve energy. Sleeping allows us to reduce our caloric needs by spending part of our time functioning at a lower metabolism.
This concept is backed by the way our metabolic rate drops during sleep. Research suggests that eight hours of sleep for human beings can produce a daily energy savings of 35 percent over complete wakefulness.
The energy conservation theory of sleep suggests that a main purpose of sleep is to reduce a person’s energy use during times of the day and night, when it’s inconvenient and less efficient to hunt for food.
Cellular restoration
Another theory, called the restorative theory, says the body needs sleep to restore itself.
The idea is that sleep allows cells to repair and regrow. This is supported by many important processes that happen during sleep, including: muscle repair, protein synthesis, tissue growth, and hormone release.
Brain function
The brain plasticity theory says sleep is required for brain function. Specifically, it allows your neurons, or nerve cells, to reorganize.
When you sleep, your brain’s glymphatic (waste clearance) system clears out waste from the central nervous system. It removes toxic byproducts from your brain, which build up throughout the day. This allows your brain to work well when you wake up.
Research suggests that sleep contributes to memory function by converting short-term memories into long-term memories, as well as by erasing, or forgetting, unneeded information that might otherwise clutter the nervous system.
Emotional well-being
Similarly, sleep is necessary for emotional health. During sleep, brain activity increases in areas that regulate emotion, thereby supporting healthy brain function and emotional stability.
Research shows that sleep and mental health are intertwined. On the one hand, sleep disturbances can contribute to the onset and progression of mental health issues, but on the other hand, mental health issues can also contribute to sleep disturbances.
Weight maintenance
Sleep affects your weight by controlling hunger hormones. These hormones include ghrelin, which increases appetite, and leptin, which increases the feeling of being full after eating.
During sleep, ghrelin decreases because you’re using less energy than when you’re awake.
Lack of sleep, however, elevates ghrelin and suppresses leptin. This imbalance makes you hungrier, which may increase the risk of eating more calories and gaining weight.
Recent research shows that chronic sleep deprivation, even as few as five consecutive nights of short sleep, may be associated with increased risk of: obesity, metabolic syndrome, and type 2 diabetes.
Proper insulin function
Insulin is a hormone that helps your cells use glucose, or sugar, for energy. But in insulin resistance, your cells don’t respond properly to insulin. This can lead to high blood glucose levels and, eventually, type 2 diabetes.
Sleep may protect against insulin resistance. It keeps your cells healthy so they can easily take up glucose.
The brain also uses less glucose during sleep, which helps the body regulate overall blood glucose.
Immunity
A healthy and strong immune system depends on sleep. Research shows that sleep deprivation can inhibit the immune response and make the body susceptible to germs.
When you sleep, your body makes cytokines, which are proteins that fight infection and inflammation. It also produces certain antibodies and immune cells. Together, these molecules prevent sickness by destroying harmful germs.
That’s why sleep is so important when you’re sick or stressed. During these times, the body needs even more immune cells and proteins.
Heart health
While the exact causes aren’t clear, scientists think sleep supports heart health. This stems from the link between heart disease and poor sleep.
The Centers for Disease Control and Prevention (CDC) says the average adult needs seven hours of sleep a night. Getting less than that on a regular basis can lead to health problems, many of which can hurt your heart health.
Lack of sleep is associated with risk factors for heart disease, including: high blood, pressure, increased sympathetic nervous system activity, increased inflammation elevated cortisol levels, weight gain and insulin resistance,
