We all know that sleep is important but we not always know exactly why or how to improve it. In his talk at the Biohacker Summit in Stockholm, Greg Potter presented the state-of-the-art scientific evidence to hack your way to better sleep and life. Watch his presentation and learn more about how to optimize your sleep!
Watch Greg Potter’s great presentation from the Biohacker Summit 2018 Stockholm video series:
Why we sleep?
Let’s start with some facts. While we sleep, we can’t eat, drink, or have sex, and we are most vulnerable. This suggests that there should have been a strong evolutionary pressure against sleeping. However, all species have a sleep behavior, and we spend 1/3 of our lives sleeping.
“If sleep doesn’t serve vital functions, it’s the greatest mistake that evolution ever made,” Greg says.
Evidence shows that in modern times we don’t really value sleep. On average, during work days, sleep duration decreased by 37 minutes over the last decade.
Moreover, humans are the only species that artificially restrict sleep, and insomnia is the second most prevalent mood disorder in Europe.
Each 1-hour decrease from our ideal 7-hours of sleep per night is associated with a 6% increase of risk of death from any cause.
There is also evidence that sleep restriction causes many functional disturbances. For example, sleep deprivation (5 nights at 4 hours per night) can make previously healthy people temporarily pre-diabetic.
Sleep deprivation increases food intake
People with regularly restricted sleep intentionally extended their sleep in the lab from 6 to 10 hours. After 10 hours, insulin sensitivity was 45% higher.
On average, sleep restriction increases energy intake by about the same amount as the number of calories in 4 apples. Over one year, this equals the amount of energy stored in 17 kg of fat.
Sleep extension reduces fat and energy intake.
People who normally sleep less and extend their sleep for 4 weeks, consume 10 grams less added sugar, carbs, and fat.
Sleep can influence decision making
Reduced sleep (4-6 hours in bed for 2 weeks) resulted in a decrease of cognitive functions.
Obese adults who extended their sleep for 15 months saw a 7% improvement in cognitive function, 10% in attention, and a better memory.
No aspects of human biology evade the negative consequences of poor sleep, and improving sleep can quickly reverse some of these effects.
Hack your way to better sleep
Let’s dig deeper. Sleep is regulated by a 2-step process.
A circadian process where wakefulness increases during the day and decreases at night. A master clock in the brain responsible for this effect: the pineal gland produces melatonin which is suppressed by light exposure.
A sleeping process where sleepiness accumulates with prolonged wakefulness and is paid off when we sleep. We need on average 8 hours in bed to feel to wake up refreshed. Residual lack of sleep will result in feeling tired in the morning.
There are sleep-promoting chemicals in the brain (somnogens) which regulate this processes. One of these chemicals, adenosine, accumulates in the brain throughout the day. Adenosine is a by-product of ATP, meaning that the more energy (ATP) we use during the day, the more adenosine we will accumulate, and thus more sleepiness we will feel at nighttime.
Stages of sleep
When awake, there is a high-frequency activity in our brain. Sleep get deeper over the course of the night, and, at the end of each sleep cycle, we enter REM sleep (muscles are paralyzed but the brain is 30% more active than during daytime). Humans spend more time in REM sleep than any other primate, and this stage is responsible for creativity and emotion regulation. Sleep cycles last approximately 90 mins and REM stages get longer with each cycle.
N3 sleep is the deepest sleep and is characterized by high-amplitude synchronized slow waves.
The new things that we learn during the day are stored short-term in the hippocampus. During deep sleep, our memories are transferred to the neocortex for long-term storage.
Also, bodily functions like planning, initiating and monitoring behaviors (executive functions), blood sugar levels and diabetes risk (metabolism) are mediated by slow brain waves, which are driven by the amount of adenosine accumulated during the day.
Practical tips to improve sleep
The more energy that your body burns during the day, the more adenosine accumulates in the brain, and the more benefits we get from deep sleep.
Other somnogens are inflammatory cytokines (IL-1beta and TNF-alpha) and prostaglandin D2. Arachidonic acid, found in beef and chicken, is a conditionally essential fatty acid and the building block for these cytokines.
In sleep deprivation, nitric oxide (NO) accumulates in the basal forebrain, which promotes sleep partially by raising adenosine levels. Nitrate-rich foods like spinach beetroot can boost NO production.
Reducing synthesis or increasing breakdown of wake promoters (acetylcholine, dopamine, histamine, noradrenaline, orexin, serotonin) or target their receptors reduces the time to fall asleep and promotes sleep duration. However, the chemicals produce tolerance and withdrawal effects (e.g., diphenhydramine).
Increasing the synthesis or reducing the breakdown of sleep-promoting neuromodulators (acetylcholine, GABA, glycine, MCH) found in medicinal plants like valerian and lemon balm increase GABA signaling in the brain but can also build tolerance over time.
Hormones like the growth hormone (GH) and prolactin also improve sleep. Exercise and sex are known to boost these hormones.
Gut microbiota plays a major role in stress response and inflammation. Supplementing with prebiotics and probiotics improves the response to stress and, thus, sleep.
Recently it has been shown that substances like chili peppers and capsinoids increase brown fat thermogenesis and this can induce sleep. Cold exposure also has the same effect but it has to be done early in the day because extreme temperatures will increase alertness.
Heating the body activates warm sensitive neurons in the hypothalamus, which increase slow wave activity. For example, raising skin temperature shortly before (within 1 hour) sleep with a hot shower will create a gradient between our core and our skin helping radiate heat out from the core. Brain temperature drops, which facilitates falling asleep.
Similarly, L-glycine improves sleep as it binds to NMDA receptors and facilitates peripheral vasodilation to help lose heat.
Our thalamus blocks external stimuli from disrupting our sleep. However, some stimuli like aromatherapy will still affect our sleep. For example, jasmine oil reduces time awake while lavender oil increases slow wave activity and sleep spindles and improves sleep quality, its duration, and enhances memory.
Transcranial stimuli (like TES, TMS, and VR) are non-invasive methods to stimulate the brain, which excite neurons and slow wave activity in specific regions improving sleep and enhancing memory.
The K complex is a sleep-protective mechanism. Timely delivery of pink noise (e.g. with Dreem) can increase slow waves and spindles enhancing memory formation.
Finally, rocking helps to fall asleep faster by stimulating the vestibular system, as a nap in a hammock would do.
Watch more presentations from the Biohacker Summit 2018 Stockholm video series here.
Greg Potter will also be sharing more of his research on sleep at the Biohacker Summit in Toronto, October 2018. Check it out if quality sleep is a priority for you.
This article was written by Evguenia Alechine, PhD.