Sleep for high performance and longevity

This sheet is structured in two parts: first, you can explore how your sleep works. Second, you get actionable advice on how you get the right amount of high-quality sleep. The reading time of the entire sheet is approximately 4 min.

Getting good and enough sleep is scientifically linked to high performance and longevity. Over 20 large-scale studies that have tracked millions of people over decades all report the same relationship: if we sleep well and enough, our cognitive abilities are significantly enhanced, we stay slimmer, and our risk for diseases are substantially lower, resulting in a longer life.^{[Walker 2018]}

How sleep works

Two independent factors dictate how alert and attentive we are when we are awake and how well we sleep: our circadian rhythm and a chemical called adenosine. The former is our “inner clock,” roughly aligned to the 24 h-cycle. The latter is “sleep pressure” that builds up from the moment we are awake.

Sleep is an active brain state and highly productive. We cycle through two types of sleep: shallow rapid eye movement (REM) sleep, and deep non-REM (NREM) sleep. During REM sleep our brain activity is similar as during wakefulness, but the body is paralyzed. We create new memory associations and we dream. During NREM sleep we move short-term to long-term memory, which is essential for learning.

For maximal performance of body and mind, sleep is more important than exercise and diet. The body needs to go through all sleep cycles each night, and there is no shortcut to “sleep faster.” The optimal bedtime is genetically individual, and everybody belongs to one of three chronotypes: 40 % have their peak wakefulness early in the morning, 30 % have it later in the morning, or even in the afternoon, and 30 % lie somewhere in-between. To truly thrive, sleep quality matters even more than our sleep times or quantity. The next two sections offer actionable tactics to optimize both.

Getting the right amount of sleep

1. Give yourself a non-negotiable 8 h sleep opportunity each night. You are biologically hard-wired for biphasic sleep, so ideally sleep for 7.5 h with no interruptions during the night plus – if possible – a 20 min “siesta” nap in the afternoon.^{[Ekirch 2016]} Do not assume you need less sleep. There are extremely few people that can sleep for only 6 h without getting impaired due to the rare gene BHLHE41.^{[Pellegrino 2015]}
2. Stick to the same sleep schedule every night to minimize variance in sleep experience, ideally even during the weekend. Determine your best wake-up time (earlier is not better for everyone) and set a bedtime alarm for 8 h before that. Tracking your sleep on a calendar is an effective way for a positive behavioral change.
3. Avoid postponing sleep to the weekend. You might subjectively feel like you get used to 6 h or less of sleep, but objectively your performance is measurably decreased: after being awake for 19 h, you have the same cognitive impairment as someone who is legally drunk.^{[Tefft 2016]} Even after three nights of recovery sleep, your cognitive performance remains lower than before the sleep deprivation.^{[Dinges 2003]}

Getting high-quality sleep

1. Sleep in a quiet, dark, and cold bedroom. Use light bedding and nighttime clothes because a decreased body temperature helps to initiate and maintain sleep. To cool down a hot body before bed, taking a warm bath is a counter-intuitive but great way to dissipate heat from your skin quickly. If you cannot control the light and sound of your environment, use an eye mask, and earplugs to achieve darkness and calm.
2. Use the bed only for sleep, intimacy, and other restful activities, like pleasure reading. This creates a strong association between the bed and rest.
3. Avoid sleeping pills. Sleep induced by such sedatives is deficient in NREM sleep and has other unwanted side effects.
4. Avoid bright light and using devices for 30 min before bed. Light suppresses melatonin, especially blue light that is often emitted from device screens.
5. Avoid large meals and beverages, especially alcohol, late at night. Alcohol might help you fall asleep, but it suppresses REM sleep and leads to non-restorative sleep later in the night.^{[Colrain 2014]} Only consume moderate amounts and long before bedtime.
6. Exercise daily to get good sleep but no later than 3 h before bedtime to let the body wind down.
7. Intake the last caffeine in the early afternoon. The half-life of caffeine is 5–7 h.

Getting a boost

If you did not get a great night of sleep but need to be attentive and alert, two things give you a boost:

1. Intake caffeine 30 min before you need peak performance. It temporarily blocks the effect of adenosine.
2. Nap for 10 min. It temporarily makes up for as much as 1 h of sleep.

There is no method to get the other benefits of sleep for more complex functions of the brain including learning, memory, emotional stability, complex reasoning, or decision‑making.