The Science of Sleep:
One of the oddest things we do every day is sleep. The average adult will sleep for 36% of his or her life. We move from the bright, intellectual, energetic beings we are during the day to a silent condition of hibernation for one-third of our life on Earth. But what precisely is sleep? Why is it so necessary and beneficial to our bodies and minds? What effect does it have on our lives while we are awake?
How Much Sleep Do You Really Need?
Alright, so sleep is important, but how much sleep do you really need? To answer that question, let’s consider an experiment conducted by researchers at the University of Pennsylvania and Washington State University. The researchers began the trial by gathering 48 healthy men and women who were getting seven to eight hours of sleep per night on average. They then divided the subjects into four groups. The first group was required to stay up for three days without sleeping. The second group slept for four hours each night. The third group slept for six hours each night. The fourth group slept for eight hours every night. Subjects in the last three groups (four, six, and eight hours of sleep) were required to adhere to these sleep patterns for two weeks. Throughout the trial, the volunteers’ physical and mental abilities were assessed.
Here’s what happened…
During the 14-day trial, participants who were permitted a full 8 hours of sleep showed no cognitive impairments, attention lapses, or motor skill reductions. Meanwhile, the sleep groups that obtained 4 hours and 6 hours of sleep decreased with each passing day. The four-hour group fared the poorest, while the six-hour group fared no better. There were two remarkable discoveries in particular. To begin with, sleep debt is a cumulative problem. Sleep debt, according to the researchers, “has a neurobiological cost that accumulates over time.” After one week, 25% of the six-hour group was sleeping at odd times during the day. After two weeks, the six-hour group exhibited performance losses comparable to being awake for two days straight. Let me repeat: if you obtain 6 hours of sleep every night for two weeks in a row, your mental and physical performance drops to the same level as if you remained awake for 48 hours in a row.
Second, participants didn’t notice their own performance declines. When participants graded themselves, they believed that their performance declined for a few days and then tapered off. In reality, they were continuing to get worse with each day.
The Purpose of Sleep:
Sleep provides several important functions for your brain and body. Let’s have a look at some of the more essential ones.
The first function of sleep is to restore. Your brain generates metabolic waste on a daily basis while it performs its usual neurological operations. While this is totally natural, an excess of these waste products has been related to brain illnesses such as Alzheimer’s disease. So, how can we get rid of metabolic waste? According to a recent study, sleep plays an important role in clearing up the brain each night. While these poisons can be flushed out throughout the day, researchers have shown that clearance during sleep is up to two times quicker than during the day.
During sleep, brain cells actually shrink by 60 percent, allowing the brain’s waste-removal system—called the glymphatic system—to essentially “take out the trash” more easily. The result? Your brain is restored during sleep, and you wake up refreshed and with a clear mind.
The Theory of Cumulative Stress:
Consider your health and vitality to be a bucket of water. There are things in your daily existence that fill your bucket. One of the primary inputs is sleep. Nutrition, meditation, stretching, laughing, and other types of rehabilitation are also included. There are additional forces at work to remove the water from your bucket. These are outputs like weight lifting or running, stress from work or school, relationship issues, or other types of stress and anxiety.
Age-Related Sleep Changes:
“As people age, it takes longer to fall asleep, a characteristic known as increasing sleep latency,” according to Harvard Medical School researchers. In addition, sleep efficiency — the proportion of time spent sleeping in bed – decreases.”
In other words, it seems reasonable to say that getting good sleep is one of your best defenses against aging quickly.
The Circadian Rhythm:
What is your sleep-wake cycle dictated by?
Answer: the circadian rhythm. The circadian rhythm is a biological cycle of different processes that happen over a time span of about 24 hours.
Here are some key points in the typical 24-hour cycle:
- 6 A.M. Cortisol levels increase to wake your brain and body
- 7 A.M. Melatonin production stops
- 9 A.M. Sex hormone production peaks
- 10 A.M. Mental alertness levels peak
- 2:30 P.M. Best motor coordination
- 3:30 P.M. Fastest reaction time
- 5 P.M. Greatest cardiovascular efficiency and muscle strength
- 7 P.M. Highest blood pressure and body temperature
- 9 P.M. Melatonin production begins to prepare the body for sleep
- 10 P.M. Bowel movements suppressed as the body quiets down
- 2 A.M. Deepest sleep
- 4 A.M. Lowest body temperature
Obviously, these times are not exact and merely display the general pattern of the circadian rhythm. The exact times of your circadian rhythm will vary based on daylight, your habits, and other factors we will discuss later in this guide.
The circadian rhythm is impacted by three main factors: light, time, and melatonin.
