We are waking up to the importance of sleep. In our most recent research report on 23,990 resilience assessments, sleep quality ranked as the #1 most important factor in order to be in the top 10% of resilience scores. There is wide acknowledgement that human sleep is disrupted. The consequences are chilling. They undermine every aspect of a good life.
Adults get about an hour a night less than needed. Teenagers get almost two hours less than they require. We go to bed too late and are overstimulated. We sleep in to recover. We live perpetually jet-lagged. Our timing and quality of sleep are disrupted from natural rhythms.
Consequences include weight gain, diabetes, inflammation, heart disease, cancer, mental illness, dementia, and attention disorders. Not to mention crankiness. Along with alcohol, fatigue is a major cause of road accidents, safety violations, and conflict. Sleep causes a loss of productivity estimated at 2-4% of GDP. Walker quotes studies showing costs to businesses of $1,400 USD per person per year as a consequence of sleep disruption. If you don’t secure your sleep, your productivity is punished.
On the positive side, sleep is the ultimate performance and anti-ageing treatment. Get a good night’s sleep, and everything works better. You are a better version of yourself. You can jump higher, run faster, connect better, think smarter, and experience more joy.
Food and water often have been in short supply throughout our evolution. Hunger and thirst became powerful drives. Long, dark, cool nights and the danger of moving about in the dark meant that time for sleep was abundant through evolution. Compared with hunger and thirst, sleep is a weak drive.
When your sleep rhythms are broken, every rhythm of your body, emotion, and mind is disrupted.
There are three elements to lock in your sleep rhythm. Sleep timing, sleep need, and sleep quality. There is no prescription that will work for everyone. For genetic, environmental, work, and family reasons, you will have to experiment. Once you find what works for you, lock it into a non-negotiable routine.
Why is Sleep Timing Important?
Sleep timing is the best time to fall asleep and wake up each day. The circadian rhythm establishes the period during which sleep is most effective. When you sleep during the right hours for your personal clock, the quality of your sleep is optimised.
In humans, the circadian clock ranges from 24 hours to 25 hours. Sleep lags behind the 24-hour day-night cycle. There are morning people and night people: larks and owls. A lark tends to have a short clock, thus gets tired early in the evening and is ready to get up early in the morning. The owl, with a longer circadian clock, gets tired later and prefers to sleep in through sunrise.
There is a dynamic relationship between the day-night rhythm and the circadian clock. The primary rhythm is set by pre-sunrise blue light. Blue light reboots the active and alert period of your circadian rhythm through the supra-chiasmatic nucleus behind the eyes.
The best way to stabilise your clock to the day-night rhythm is to get 20 minutes of pre-sunrise blue light. This becomes the foundational rhythm for all other biological rhythms. Physical activity, light, coffee or tea, social activity, refined carbohydrates, and mental habits can also adjust your circadian clock, for better or for worse.
Blue light in the evening will wake you up right when you need to prepare to sleep. We come home to blue LED lighting, TV screens, laptops, and mobile devices. In addition, we socialise, drink, and eat late. Your clock gets pushed toward later sleep onset.
Sleep Phase Delay is a common sleep disorder that pushes us to sleep too late. We are perpetually jet-lagged and pressed into behaving more like an owl. There are established physical and mental health risks for the owl pattern. Recent studies show that there may be benefits to behaving more like a lark. This is certainly true for a lark and looks hopeful for the owl.
Beware of the weekend sleep-in. Roughly 30% of our clients sleep in later through the weekend to catch up on sleep. This is exaggerated in males under 30. After a busy and sleep-deprived week, sleeping into the day allows your circadian clock to “free-run” a couple of hours into the next day. The quality of this “extra” sleep is poor. It leaves you jetlagged through the next week.
The single most effective action to start is to wake up with or before dawn. Ideally, be outside in dawn blue light. This is especially true on weekends. The best blue light is just before sunrise.
Tracey, a participant on a course some years back, argued vehemently against losing the pleasure of a weekend sleep-in. Six months later, she grabbed my shoulder on a flight. She said: “When you explained the importance of wake-up times, I hated you. However, my husband and I have followed your plan. Our energy and our weekends have improved dramatically. Thank you”.
Next, you must take care of the cool-down period. If you rise early and press into the night with blue-light stimulation, you will sleep-deprived. Sadly, many ask me what they can do if they cannot stare at and fidget on a screen.
Our needs are different. I suggest that for 90 minutes before sleep, you read a book, play a game (cards, jigsaws, board games), meditate, write (in a journal or notepad, not via a screen), talk, take a walk, stretch, take a bath, or make time for intimacy.
It is essential to avoid blue light from screens before sleep. Replace LED lighting with soft yellow lighting. Eat dinner early. Limit alcohol.
Figure 1: Schematic illustration of the circadian cycle
During this period, you want to shift heat from your core to your periphery. The body releases melatonin in the evening to help cool your core temperature slightly. When exposed to blue light, melatonin is compromised. An easy walk outside or a cool bedroom will help. Aim for 18 degrees Celsius (about 65 degrees Fahrenheit) or cooler if possible. Intense exercise in the four hours before sleep is not recommended as it increases your core temperature. A cold shower or ice bath is helpful to some.
The final key is to apply your Tactical Calm techniques as you relax into sleep. Lie relaxed and flat on your back. Soften your face and chest. Breathe slowly, with your attention resting peacefully on the rise and fall of your belly.
Sleep Quantity Varies Per Person
Sleep need is widely agreed to be somewhere between six and a half and eight hours. It is based on the S-phase, the requirement for the body to sleep for a period of each day. If we sleep too little or too much, the prospect of a good life declines fast. Every species has its own sleep need. We need more than most mammals our size. Our overdeveloped brain demands it.
Experiment and study your own requirement. The natural way is to go camping, live by natural light for three days and see what happens. Many people now use sleep trackers. Buy or borrow one and watch your sleep for a fortnight.
When you review the data on a sleep tracker, you will notice that your body keeps hunting for a consistent sleep period. Pay attention to how you feel when you get it and when you miss or exceed it. In my case, the magic number is seven hours and twenty-two minutes. When I get it right, I feel refreshed. Too little or too much, and I feel sleepy or lethargic.
The Science Behind Sleep Quality
Once you have established the right timing and protected your sleep need, the next challenge is to get your ultradian rhythm working. Think of this as your sleep-depth rhythm. The ultradian rhythm is a 90-minute cycle that allows for roughly two cycles of deep sleep followed by two or three cycles of dream sleep. When you get this right, the rejuvenation effects of sleep are optimised.
Simple trackers will give you an immediate, rough indication of your deep, light, and dream sleep. For an adult, approximately 25% of sleep is in deep (slow-wave) sleep, 25% in dream or rapid eye movement (REM) sleep, and 50% in light sleep. Your teenager and child need more deep sleep as well as more sleep.
In the cycles of deep sleep that follow falling asleep, the brain and body are both quiet. Core body temperature drops. This is the time for the repair and rejuvenation of cells. Growth hormone and testosterone production activate. The cardiovascular system slows right down. Immunity improves.
In light sleep, the body is more active and in transition.
During the dream cycles through the early morning hours, the brain is active while the body is paralysed. If not, we might act out our dreams and sleepwalk. Dreaming sleep facilitates memory, learning, creativity, emotional intelligence, and recovery from traumatic experiences.
Figure 2: Schematic illustration of the sleep cycles and ultradian rhythm
Deep sleep is prioritised if you are deprived of sleep. The best deep sleep comes in the 10 p.m. to 2 a.m. period. As we get older, deep sleep is less effective. Deep sleep is an effective longevity tactic.
Late nights compromise your dream sleep cycles. To reduce mental illness and anxiety in young people, an obvious first step is to help them get to sleep earlier so that they complete their dream sleep. Quality sleep will reduce the suffering caused by attention disorders, anxiety, and depression. As parents, we have two key responsibilities to our children. First, get devices out of the bedrooms. Second, maintain a regular, blue-light-infused wake-up time.
There will be times when healthy sleep is disrupted. Accept this calmly and make it up quickly. The best solution, if you need to repay sleep debt, is to go to bed the next night an hour or so early. Eat early or eat less at night. Remove all devices, cool the room, and read a book. You may like to test a light surgical tape over the lips to prevent snoring and encourage nasal breathing.
Why You Should Stop Thinking in Bed
In my experience, about a third with sleep difficulty wreck sleep with unhelpful thinking. When you secure a good night’s sleep, there is no conscious thought. It is easy to let a storm of thoughts into your bed. Worry (repetitive thoughts about the future) will generate anxiety and destroy sleep. Rumination (repetitive thoughts about the past) will generate sadness or anger and destroy sleep.
Ban thinking from the bedroom. If thoughts arise, refocus on slow diaphragmatic breathing. Watch the rise and fall of your belly. Feel your body relax and dissolve on the exhalation. With a few weeks of practice, you will be amazed how your mind stops bothering you. Make it a habit and stay committed. Sleep can be very peaceful.
Finally, a short power nap of ninety seconds to fifteen minutes is another effective way to catch up on sleep. Ideally, the best time is just after lunch. Find a private, quiet, cool, and dark place. Set the alarm. Use your breathing to drop off more quickly. If sleep does not come, simply enjoy the rest.
In summary, these 10 tips will help you to improve your sleep:
- Explore and track your sleep timing, need and quality.
- Wake up and go outdoors for 20 minutes before sunrise.
- Never sleep in. Never snooze.
- When you wake, get out of bed.
- Create a cool, quiet, yellow-light evening environment.
- Avoid all screens for 90 minutes before sleep.
- Let your body cool before sleep (maybe a cold shower or ice bath?)
- Engage in slow diaphragmatic breathing practice.
- Enjoy nature’s gift of deep, quality and unbroken sleep.
- Be ruthless in forbidding thinking from your bed.
Sources:
Walker, Matthew, Why We Sleep, Penguin, 2107. A very popular and helpful overview of sleep science.
Nestor, James, Breath, Penguin Books, 2020.
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