Sleeping isn’t just a hum-drum, daily activity to be taken for granted, it’s a highly active period where we rest and repair our bodies and our minds. As we sleep, our brains continue to function in a way that maximizes the benefits of sleep as they pertain to our health and wellness. In the midst of dreaming, detoxifying, and consolidating our memories, we transition in and out of sleep’s many stages. All the while, our conscious mind becomes blissfully unaware as we slip deeper into dreamland.
What is The Sleep Cycle?
During sleep, we cycle between stages of rapid eye movement (or REM) and non-REM sleep. (Who knew that something as trivial as eye movement could have such a profound effect on our brain!) Unlike simply averting our glance from point to point as we do during waking hours, in REM sleep our eyes move quickly in many different directions.
But, REM sleep isn’t reached immediately; instead, we gradually drift from one sleep cycle to the next. As we sleep, this process continues over and over again until we awake with a renewed sense of vigor.
- In the first stage, you enter a state of non-REM sleep that only lasts about five to ten minutes; during this stage, we are easily disturbed.
- In stage two, your body prepares for deep sleep- your heart rate slows, and your body temperature drops.
- In deep sleep (which commences in stage three), you become increasingly difficult to awaken, and your body focuses its attention on the repair and regrowth of tissues, bones, and muscles…even your immune system is improved!
- In stage four, you enter an even deeper state of rest that lasts for approximately thirty minutes. If you know someone who’s experienced episodes of sleepwalking or bedwetting, the end of stage four sleep is the time these behaviors will typically manifest.
- Once we reach a period of REM sleep, our heart rate and breathing increase, and we begin to experience the phenomena of dreaming due to heightened brain activity.
The Benefits Of REM Sleep
While it takes at least ninety minutes to reach this stage, it only last for about ten minutes…at first. As we continue to sleep, however, the stages of REM sleep increase in duration with the last one topping out at almost a full hour!
When we’re in REM sleep, our body focuses its energies on the brain. To do so, the brain sends a signal to our body that actually turns off the neurons in our spinal cord; in turn, we enter a state of temporary paralysis.
According to the National Institute of Neurological Disorders and Stroke, REM sleep stimulates the regions of the brain which are engaged when we learn. While we know that sleep can improve our capacity to absorb and retain new information, it’s interesting to know that infants spend significantly more time in REM sleep that adults.
In an American Psychological Association interview with James B. Maas, Ph.D., Maas touts REM sleep for its important role in “helping people learn and remember how to perform physical tasks.”
While Maas credits good sleep as “the best predictor of lifespan and quality of life, ” he explains how REM sleep, specifically, provides opportunities for 1.) new information to be stored as long-term memory, 2.) the replenishment of neurotransmitters that “organize neural networks essential for remembering, learning, performance and problem solving,” and 3.) the brain to make sense of daily events through dreams.
He continues, “Your alertness, energy, performance, thinking, productivity, creativity, safety and health will be affected by how much you sleep.”
How Our Sleep Cycles Change As We Age
Psychology Today also uncovers interesting data that shows a clear association between our age and our sleep cycles:
- As we age, we not only require less sleep, but we also spend less time in deep sleep and REM sleep.
- In adolescence, we experience the greatest reduction of time spent in non-REM deep sleep. In fact, about 40% of non-REM deep sleep is replaced by Stage 2 sleep.
- Babies can enter REM sleep the moment they fall asleep! While infants spend half of their time asleep experiencing the REM stage, this is reduced to 25% by age two.
If you’re not getting 7-8 hours of sleep each night, you may be cutting your REM sleep short! Since REM sleep increases through the night, the hours nearest waking contain the longest periods of REM sleep. In order to reap the benefits of sleep in all it’s stages, find out just how much sleep you need and make getting quality sleep a nightly priority.