What is sleep?

Sleep is an active part of our life that is critical for our well being. Everybody does it, and yet it is surprisingly tricky to describe what “it” is that we’re doing when we are asleep.

Fundamentally, sleep is a neurological process. The brain goes through a set of natural rhythmic oscillatory states that facilitate cellular growth and repair, memory encoding, and learning. Sleep consists of two major types of sleep - rapid eye movement (REM) sleep and non rapid eye movement (NREM) sleep - both of which are critical to our health. When you go to sleep for the night, you go through multiple cycles of NREM and REM sleep.

The cycle begins with "light sleep" - a drowsy state (N1), followed by perceived sleep (N2) with relaxation of muscles, breathing, and heartbeat. Light sleep stages form the majority of the duration of sleep. It is followed by slow brainwave states called "deep sleep" (N3). The brain wave oscillations slow down and muscle tone also decreases. This is the state from which it is the most difficult to wake up. After this stage comes REM sleep - where the brain activity while dreaming resembles the wake state, accompanied by rapid eye movements and loss of muscle tone.

These sleep stages do not always occur in sequence - with some skips, some transitions back-and-forth between the sleep stages occurring often, which can make the sleep be fitful or restful - leading you to feel less or more rested and refreshed.

The amount of sleep one needs changes as they age - with the longest needs for babies, followed by kids till their teen years, and stabilizing in adulthood (typically at 7-9 hours per night).

In addition to age, there are several factors that influence the sleep cycle, including genetics, environmental factors (like light, temperature, noise, or comfort), and medical and psychological conditions (like anxiety, stress, pain, or obstructive breathing). You can control some of the environmental factors, but it is not always possible to trace how all of these factors come together to affect the brain state, which in turn affects sleep health.

At StimScience, we’ve spent years studying how to directly stimulate the brain to promote states that naturally facilitate better sleep. In our sleep labs, our technology helps people to fall asleep faster, stay asleep longer, and achieve a deeper, higher quality night’s sleep.