Sleep has a bigger impact on our mental, emotional and physical performance than any waking activity – there is no more powerful brain enhancer.
When we sleep, we consolidate memories and experiences, detox the brain of waste products and regenerate brain cells. This makes a profound difference to our daily performance, enabling us to think clearly and deeply, focus well and handle multiple challenges with ease.
Have you ever woken up in the morning with an insight or solution to a question that had you stumped? You have a good night’s sleep to thank for that. Have you ever had the experience of practising a specific skill (such as a sport or musical instrument) where you repeated an exercise again and again but the coordination just wouldn’t come, then, the next day, suddenly the practice paid off and you were able to perform? Sleep is responsible for this, too. Research from the University of Lubeck, Germany, in 2004 was the first to show how sleep facilitates insight by helping us connect implicit knowledge and memory with explicit knowledge that we have recently gathered, generating that sudden light-bulb moment.
While we sleep, an army of nervous system support cells (glial cells) in the brain is working hard to support and repair neurons, enabling us to learn not just motor skills, but absolutely anything that has been of benefit or interest to us during the day. They reinforce neural pathways, clean up toxins, deliver nutrients and transport new neurons from their origin to their destination. As we learned in the last chapter, glial cells also rebuild the myelin (insulating fat) sheaths around the most-used neurons in our brains, better protecting them and minimising signal loss when our neurons fire. With enough good-quality sleep, all these processes are completed, brain fog clears, and we have more cognitive power.
The body also recuperates while we sleep. Our liver catches up on processing sugars and fats and regenerates liver tissue. The parasympathetic nervous system produces acetylcholine (the recovery and renewal chemical) and the adrenal glands replenish their stocks of steroids, such as DHEA and testosterone, in preparation for the next day’s activity. Muscle fibres heal at a faster rate than during the day and the lymph system drains toxins out of all the tissues in the body, rejuvenating the skin, muscles, tendons, ligaments, organs and the circulatory and excretory systems. The mind processes thoughts and emotions, matching them against memories and deciding which to store in the long- term memory, which to retain in the short term, and which to discard, sometimes representing such links through our dreams. A whole lot of clever regeneration is going on behind the scenes while we are asleep.
Many of us, however, are getting less sleep than we need. A study by RAND Europe in 2016 concluded that fatigue- related productivity losses in the UK amount to £40 billion. It also found that if we were to increase sleep time from under six hours to between six and seven hours, we would add £24 billion to annual productivity. In the same study, US losses were estimated to cost $1,967 per employee annually, approximately $400 billion in total. Data from the American Sleep Foundation shows that 40 per cent of Americans receive under seven hours of sleep a night. The RAND report puts a 13 per cent higher mortality risk on those who receive less than six hours sleep, which improves to 7 per cent for those who receive between six and seven hours. Neurologist Dr Itzhak Fried at UCLA is the most recent researcher (among many others) to demonstrate that performing on lack of sleep is equivalent to performing while drunk. His 2017 study reveals how sleep deprivation disrupts brain cells’ ability to communicate with each other. Mental lapses increase while reaction times decrease significantly on low levels of sleep. This means that, if driving without sufficient sleep, the very act of seeing a pedestrian step in front of the car takes longer: the brain is slower to register what it is perceiving.
So, what is the correct amount of sleep, and how do you know if you are getting it? Advice from the University of Loughborough School of Sport, Exercise and Health Sciences says that ‘if the sleep you obtain allows you to awake feeling reasonably refreshed, to function efficiently the next day, and to conduct your affairs without experiencing intrusive episodes of fatigue, then you are probably getting enough’. Good advice, but let’s get more specific. Research by Dr Jessica Payne at the University of Notre Dame indicates that 97.5 per cent of people perform best on seven hours of sleep or more, and those of us between the ages of eighteen and sixty- four should get seven to nine hours of sleep a night. This seven to nine principle is widely accepted and borne out in many other studies across the globe, including the Sleep Council (UK) and the National Sleep Foundation (USA). Eliminate the guesswork around how much sleep you're getting by using one of the various tools/apps available to help us track and analyze our sleep. They provide invaluable insight into the amount and quality of your sleep.
How can we get more sleep? We need to mix it up…
The way forwards is a combination of increased night-time sleep, daytime power naps and proxy sleeps all working together to get us to that magic total of somewhere between seven and nine hours of sleep.
Inching up the hours you sleep
If you are a habitual six-hour sleeper, adding just twenty or thirty minutes to your sleep time every night is an effective way to start, gradually building up to that all- important seven hour threshold. It takes time to reset sleep habits, so don’t be discouraged if this takes a month or two. Start by going to bed thirty minutes earlier. Set an alarm on your phone to tell you it is time to start your wind-down routine; for example, begin by turning the lights down low, taking a hot bath, and slowing your breathing down. Give yourself plenty of time so that you are not rushing about as you get ready for bed. Experiment with how long you need and create a reliable routine.
The art of power napping
For people with uniquely challenging schedules, being smart with your time and with your naps is one effective way to get the sleep you need. Here’s how Jarrod Barnes did it when he was playing football at Ohio State while studying for his doctorate. He told us:
‘I was in graduate school as a student athlete, which was unusual. I finished my Masters’ and started my PhD in my last two years playing football, so I had to work out how to get enough sleep to be successful academically and athletically. I would get up at 4:30am to do college work and football prep early in the day, be in class or study all morning, then have a 20 minute nap at noon, prior to practice and lunch. Practice would run from 1:30pm to 7:30pm, then I would take a short 15 minute de-stressing nap at 7:45pm. After that I would eat, do whatever other work needed to be done, and get my head down again as soon as I could by 8:45 or 9pm.’ Jarrod had to find a routine that worked for him, and with this approach he totalled close to nine hours of sleep.
Short, intense periods of body and brain rest lasting two to five minutes are beneficial. This is called a ‘proxy’ sleep. You don’t actually fall asleep, but your brain goes into an immediate resting place, increasing helpful theta and delta waves that refresh the brain. This really works between challenging tasks or at the beginning of brain tiredness.
Like Jarrod, think strategically and create a plan that works for you. Check out our recent blog for more than 20 additional simple tips to transform your sleep.
Now, get some sleep!
About Companies in Motion
There are over 80 easy to use techniques and tips to build our Physical Intelligence. You can read about all of them in our new book, Physical Intelligence: Harness Your Body’s Untapped Intelligence to Achieve More, Stress Less and Live More Happily available from Simon and Schuster. (Order here.) (Multiple translations will be available later in 2019.)