What Happens When We Sleep? Understanding the Benefits of Sleep Cycles

August 22, 2021

We’ve all had to pull an all-nighter, but some have taken it to the extreme. Take 17-year-old Randy Gardner, for example: In 1964, he set the world record for enduring the most consecutive days without sleep: 11 days, 25 minutes. Researchers who monitored Gardner’s condition reported cognitive and behavioral changes, including moodiness, memory, paranoia, and even hallucinations. After achieving the title, he slept for 14 hours and 40 minutes and reported episodes of insomnia even years later. 

Of course, Gardner’s record has been repeatedly broken. Eventually, Guinness World Records discontinued the record for sleep loss due to health concerns. Gardner’s experience, and those that followed, illustrated the profound effects a lack of quality sleep has on our mental and physical health

The long-term consequences of interrupted sleep may surface in a weakened immune system, heightened risks of diabetes, heart disease, dementia, obesity, and a host of severe conditions. Given that 62 percent of adults worldwide say they don’t sleep as well as they’d like, and almost 70 percent of us report sleep disturbances at least once every night, this is great cause for concern. 

Besides measuring how you feel in the mornings, what constitutes a good night’s sleep? Let’s examine the stages of sleep, the functions of sleep, and what solutions are available to take back your nights.

The Stages of Sleep

Sleeping has four measurable stages that support critical biological and therapeutic functions. Adequate sleep allows each stage to create essential biological and restorative functions. 

Stage One: (N1) Initial Non-REM Stage

This is the dozing-off stage, where your book falls off your lap without you realizing it. This stage typically lasts one to five minutes. The pineal gland begins to regulate certain hormones to promote sleep and cellular restoration. As the body starts to relax, the autonomic nervous system transitions from the sympathetic state to the parasympathetic state.

Stage Two: (N2) The Non-REM Stage

During Stage Two, the body begins to enter a relaxed state which will allow critical functions, such as building immunity and healing injuries. Core body temperature lowers, and muscles start to relax. Breathing becomes slower and more methodic, and the heart rate begins to slow down.

Stage Three: (N3) Final Non-REM Stage

Stage three is the deep sleep stage. Muscle tone, pulse, and breathing rate decrease while the body experiences further relaxation. Deep sleep contributes to insightful thinking, creativity, and the development of long-term memories. During this stage, information gathered during the day is processed and stored for future recollection.

Stage Four: REM Stage (Rapid Eye Movement) 

During REM sleep, brain activity increases. The body becomes temporarily paralyzed. Eye movement is rapid, and the muscles that control breathing are active. REM sleep is essential to cognitive functions like memory, learning, and creativity. During REM sleep, vivid dreams occur. REM sleep allows the brain and body to restore and rejuvenate.

The result of a complete sleep cycle? “Besides leaving you rested, less stressed and more energized, a good night’s sleep is a real game-changer for your health,” says Mercy Livingston. According to the CDC, seven hours of sleep every night is the minimum recommended amount for adults ages 18-65 to sustain comprehensive health benefits. 

Vital Functions of Healthy Sleep

Emotional Well-Being

Healthy sleep is necessary for emotional health. During sleep, specific brain regions are actively regulating emotion while supporting healthy brain function and emotional stability.

Cellular Restoration  

Our body’s cells restore themselves during deep, restful sleep.

Energy Conservation

The energy conservation theory reveals how our body conserves energy during sleep by enabling our body to reduce caloric requirements.

Weight Regulation  

Sleep affects your weight by controlling hunger hormones. Specific hormones, including ghrelin, which increases appetite, and leptin, which increases the feeling of being full after eating, are regulated during sleep.

Proper Insulin Function 

Some studies suggest sleep may protect against insulin resistance. By keeping cells healthy, they can process glucose more efficiently. The brain also requires less glucose while sleeping, which may help the body regulate overall blood glucose.


Your body makes cytokines during sleep. Cytokines are unique proteins that fight infection and inflammation. Specific antibodies and immune cells form during healthy sleep. These molecules help defend against illness by destroying harmful germs.

Heart Health 

Did you know someone dies from heart disease every 36 seconds? It’s the leading cause of death in the US. Scientists have also found that 70 percent of heart disease sufferers have obstructive sleep apnea, a common sleep disorder. 

Solutions for Better Sleep

Most of us encounter occasional bouts of insomnia (the most common sleep disorder), but if you experience regular nights of interrupted sleep, there may be something more serious going on.  

As the second-most common sleep disorder, obstructive sleep apnea occurs when the muscles in the back of the throat relax, which blocks the airway. Despite the fact that around 22 million people suffer from this serious, sometimes life-threatening disorder, most of us don’t know we have it. The first step for finding solutions is to talk with a healthcare provider. 

If you wake up numerous times during the night gasping for breath, experience chronic snoring, headaches, irritability, or severe drowsiness during the day, the best resource is your dentist. Their expertise in sleep medicine and the fact that they see patients twice per year means they have a solid patient history and can quickly identify changes in a patient’s mouth

“By getting a patient’s full medical history, a dentist can identify symptoms and refer them to the appropriate doctor. Then, following a physical evaluation, diagnosis, and sleep test, the dentist can help determine if an oral device could be an effective treatment solution,” says Carl Rosenberg, MD. 

Although CPAP and other large electronic devices are common treatments for sleep disorders, many dentists are skilled in providing innovative, noninvasive non-pharmaceutical options for mild-to-moderate obstructive sleep apnea. Be sure to ask your dentist about new modern treatment methods. 

Never underestimate the value of a good night’s sleep. If conditions are keeping you awake at night, your dentist can find ways to make sure your body has the tools it needs for rejuvenating, rebuilding, and renewing, REM-quality rest.