Have you ever wondered why we, as human beings, spend approximately one-third of our lives sleeping?
From an evolutionary point of view, thousands of years ago, when we were hunters and gatherers living in hostile environments, going to sleep meant becoming vulnerable to predators and danger. If we look at the animal kingdom, all animals engage in some sort of rest and sleep. Some animals, like dolphins and whales sleep with half their brain resting at a time, with the other half awake to maintain life-necessary movement. When birds need to be vigilant during sleep, one half of the brain remains alert and one eye stays open!
So why didn’t Mother Nature create humans into a species that could live with not much – or no sleep at all?
Why don’t we sleep with one eye open? For humans, sleep is so essential that we could live for a few weeks without any food, some days without water, but after only 2 or 3 nights without sleep fatigue starts to set in and our bodies start to suffer on many levels. Routinely sleeping less than 6-7 hours a day can lead to chronic sleep deprivation which then depletes the immune system and increases the chances of developing diabetes, heart diseases, stroke, depression and Alzheimer’s disease.
What happens during sleep?
When we sleep, the brain slows down and rests. This improves our ability to learn, memorise and make logical decisions and choices. By resting and “re-setting” our brain circuits every night, sleep helps us process our emotions and helps maintain a healthy mental state.
When we dream during sleep it inspires our creativity and problem-solving skills!
Physically, when we are sleeping the cells of our immune system are replenished, hormones related to blood sugar and appetite are regulated and a healthy microbiome is promoted in the gut. Sleep also lowers our heart rate and blood pressure, maintaining the health of our hearts.
Sleep quality is the key for optimal health.
Even though sleep quantity is important (most people need, on average need 7-9 hours of sleep per day) sleep quality is the key for optimal health. During the night, approximately every 90 minutes we go through different cycles of sleep called REM (Rapid Eye Movement) and non-REM. During each cycle many essential functions and processes take place to repair, replenish and rejuvenate the body.
Missing some parts of a cycle means missing its benefits. For example, going to bed late reduces the amount of non-REM sleep we get. This is the restorative phase of sleep. This is the time our brain is deleting all the unnecessary information we have accumulated throughout the day and storing the important ones. This is called memory consolidation. Think of it like an auto-update on your computer. By waking up too early, we risk missing part of the REM cycle. This is the time we dream and our problem solving skills and creativity are enhanced.
“Sleep hygiene” is a popular term used these days to describe good sleep habits.
The human body follows a natural rhythm like a 24-hour “internal clock”. This rhythm, known as the “circadian rhythm” is connected to day and night cycles- essentially the cycle of the sun. The circadian rhythm programs us as such to be awake during the day from sunrise, and to start to feel sleepy soon after dusk- when natural sunlight fades and the temperature drops. This is when a hormone called melatonin- our sleep hormone starts to be released. The production of melatonin is dependent on the sunlight we receive during the day. When sunlight passes through our eye, it travels down the optic nerve and stimulates the pineal gland to make melatonin.
How can you improve your “sleep hygiene”?
Our 6 top tips are:
1. Avoid consuming caffeine after noon.
As a stimulant, caffeine takes over 7 hours to be completely cleared out from the brain. It competes with a substance in the brain called adenosine which is responsible for building up our “sleep drive” during the day, Food and drinks that contain caffeine such as coffee, black tea, green tea, dark chocolate and even ice cream should ideally be avoided after lunch.
2. Reduce Your Digital “Screen Time”.
The stimulation from artificial lights, especially the blue light from screens, interferes with the release of melatonin, as it tricks our brains into believing that the sun has not set yet. It is important to avoid screens for at least 2 hours before bed, remove digital devices from the bedroom and also keep the bedroom as dark as possible through the night. On the other hand, starting the day with exposure to sunlight is a great way to stimulate the production of cortisol, the hormone that drives us to be active.
3. Ensure you are sleeping at a suitable temperature.
To successfully initiate sleep our core temperature needs to decrease about 1°C. Keeping a cool bedroom temperature, having a bath before bed and selectively warming the feet and hands are known natural ways to promote sleep.
4. Be consistent with your sleep routine.
Going to bed and waking up around the same time every day, including weekends, helps to regulate the circadian rhythm and promotes good sleep quality.
5. Ensure you are getting enough regular exercise.
Regular exercise is a simple way to improve sleep quality. It helps to increase the non-REM sleep , decreases the sleep onset. This is how long we take to fall asleep- ideally this should be no longer than 20-30 minutes. Exercise also improves sleep duration. Aerobic exercise at least 3 times a week- preferably outdoors and in the morning also improves sleep quality.
6. Eat a healthy diet and at appropriate times.
Ideally the last large meal should be at least 2-3 hours before bed time. Having a heavy meal before bed or going to bed hungry can affect the quality of sleep and hormone production.
More and more research is showing us that a good night of sleep is one of the single most effective ways you can to replenish your mind, body and spirit!
Why not make your bedroom your sleep sanctuary- a place to rest and rejuvenate and practice self-care? Perhaps wind down before bed by reading a relaxing book, practicing meditation and breathing techniques, listening to calming music or giving yourself a massage with calming oils such as lavender.