Why We Sleep
What’s going on when we close our eyes?
Sleep – a quarter to a third of our lives are dedicated to it. But what's really going on when we drift off into the realm of dreamy dreams? Long gone are the days when sleep was considered a dormant period for our bodies and brains. Today, researchers like Dr. Mark Wu, a sleep expert and neurologist from Johns Hopkins, are shedding light on the dynamic activities that unfold during slumber, activities that profoundly impact our quality of life. In this article, we'll take a peek into the intriguing discoveries made by sleep researchers and delve into the fascinating world of sleep science.
Not All Sleep Is Created Equal
As we journey through the night, our brains engage in a rhythmic dance between two distinct types of sleep: REM (rapid eye movement) sleep and non-REM sleep.
The sleep cycle begins with non-REM sleep, comprising four stages. The first stage bridges the gap between wakefulness and sleep. Stage two is characterized by light slumber, marked by regulated heart rate, breathing, and a drop in body temperature. Stages three and four are deep sleep phases. Surprisingly, recent findings indicate that non-REM sleep is even more critical than REM sleep for learning, memory, and overall restorative functions.
Once we transition into REM sleep, our closed eyelids flicker with rapid eye movements, and our brain waves resemble those during wakefulness. Breathing quickens, and temporarily, our body becomes immobilized as dreams unfold.
The sleep cycle repeats itself throughout the night, with each iteration featuring less time in the deeper stages three and four and more time in REM sleep. On an average night, you'll cycle through this process four to five times.
The Inner Workings of Sleep Regulation
According to Dr. Wu, sleep regulation primarily relies on two key processes: circadian rhythms and sleep drive.
Circadian rhythms are managed by a biological clock in the brain, which responds to light cues. It orchestrates the release of the sleep-inducing hormone melatonin at night and switches it off in response to light. Those with total blindness often struggle with sleep due to their inability to detect and react to these light signals.
Simultaneously, sleep drive plays a crucial role. Your body yearns for sleep, much like it craves food. Throughout the day, your desire for sleep accumulates, and once it reaches a certain threshold, sleep becomes a necessity. Unlike hunger, your body can compel you to sleep, even during meetings or while driving. When exhaustion strikes, your body can sneak in microsleep episodes lasting just a second or two, even with your eyes open. Beware, though – napping for over 30 minutes later in the day can disrupt your nighttime sleep by diminishing your sleep drive.
The Vital Role of Sleep
If you've ever experienced mental fog after a restless night, you'll understand the profound impact of sleep on brain function. Sleep is crucial for "brain plasticity," the brain's ability to adapt to new information. Inadequate sleep impairs our capacity to process and remember what we've learned. Additionally, it's believed that sleep facilitates the removal of waste products from brain cells, a process less efficient when we're awake.
But sleep isn't just for the brain; it's a holistic necessity. Inadequate sleep heightens health risks, exacerbating symptoms of depression, seizures, high blood pressure, and migraines. Immunity takes a hit, making us more susceptible to illnesses and infections. Sleep also plays a role in metabolism; just one night of missed sleep can trigger a prediabetic state in an otherwise healthy individual.
As Dr. Wu aptly puts it, "There are many vital connections between health and sleep." So, as you embark on your journey to better sleep, remember that you're not just improving your nights; you're investing in your overall well-being.
Sweet dreams await!
