The world of sleep is complex, and we are still learning about what exactly it does for our bodies. We do know it has a big part to play in our health. As our external world is shut out while we rest, our internal world is awake and active, getting to its various duties that support us to be our best selves when we wake up.
Our internal world is active in different ways throughout the night depending on which stage of the sleep cycle we’re in. Stage 1 occurs as we first fall asleep where brain waves, heart rate, and eye movement begin to slow down. Body temperature decreases and the body continues to relax in Stage 2. Deep sleep starts in Stage 3, where everything slows down even more as the body goes into recovery mode. This stage allows the body to replenish its energy and repair cells, tissues, and muscles. Finally, in Stage 4 REM (rapid eye movement) sleep occurs. Brain waves, heart rate, and breathing actually start to increase. Dreaming is most common in Stage 4. Our brains are able to process information during this time, which is important for learning and memory. Getting through a complete sleep cycle can take anywhere between 70 and 120 minutes. The cycles towards the beginning of the night consist of more time spent in non-REM sleep. Most REM sleep happens during the second half of the night. This is why getting enough sleep is crucial, as it is most restorative towards the end of the night. Getting somewhere between 7 to 9 hours of sleep is what the average adult should be aiming for.
While asleep, the body is able to support the cardiovascular and immune systems. It helps regulate the metabolism. Our circadian rhythm, or the body’s internal clock, greatly impacts and can help regulate the production of many hormones, including melatonin (sleep), growth hormone (bone, muscle, and metabolism), cortisol (stress), as well as leptin and ghrelin (appetite). There are also many theories about what our bodies do and support during sleep. Some of these benefits include energy conservation, cellular restoration, brain function, emotional well-being, weight maintenance, proper insulin function, immunity, and heart health. Research also suggests that sleep is the period of time the brain is able to flush itself of toxic molecules.
There is still much to learn, but what’s indisputable is the importance of sleep. We’ve all discovered this in our own personal studies comparing a day after a full night’s sleep with a day after barely getting any. The effect is immediate and obvious. Sleep isn’t for the dead, it’s for the living who want to feel truly alive.