What is sleep?

We spend a third of our lives asleep. Some people enjoy sleeping, others wish they could finally get their sleep problems under control.

For many people, work takes priority in life, and long working and commuting hours mean that social and family life is reduced to late evenings and weekends. In our performance-oriented world, it sometimes feels like sleep is a sign of laziness or weakness. In interviews, successful politicians and managers like to proudly reveal that they have trained themselves to get by on just five or six hours of sleep. However, recent scientific studies show that a lack of sleep causes extensive changes in the body and increases the risk of serious health problems such as obesity, illness and even early death.

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How does sleep work?

Sleep is regulated by two factors: the biorhythm and sleep pressure.

The biorhythm determines when we wake and sleep, but also controls many other bodily processes, such as hunger and thirst, mood and emotions, urine volume, body temperature, hormone secretion, blood pressure and metabolic rate. It has a profound effect on health. Research on shift workers has revealed both psychological and physiological problems as a result of a disturbed biorhythm. We recently wrote about how light affects the biorhythm.

The biorhythm is generated internally in the body, meaning it is not solely dependent on light, although light does play an important role. In 1938, two American researchers - Kleitmann and Richardson - spent a month in a deep cave without natural light. They lived only by their internal clocks, going to work when they thought it was day and sleeping when they thought it was night. They discovered that the biorhythm is a little longer than 24 hours. Later research showed that it is 24 hours and 15 minutes. In a natural environment, it is reset to 24 hours every day by the influence of light, the night-day rhythm.

This happens via the suprachiasmatic nucleus (SCN), a tiny area in the brain that receives a dark or light signal via the optic nerve. The SCN controls the "brain clock" and generates a 24-hour rhythm that sends rhythmic instructions to all tissues of the body. The SCN regulates brain and body processes that are supposed to keep us awake during the day and switches them off for the night. For example, it influences our core body temperature. It peaks in the late afternoon, then drops near the typical bedtime and reaches its lowest point around 2 a.m. - regardless of whether we sleep then or not.

The biorhythm also regulates the antagonistic hormones cortisol and melatonin.

The second factor that regulates our sleep is'sleep pressure'. It is caused by the gradual build-up of the neurotransmitter adenosine in the brain. The build-up of adenosine begins when we wake up. It continues to rise throughout the day and reaches its peak after 12-16 hours of wakefulness. Then we feel the urge to sleep. During sleep, an enzyme breaks down the adenosine again. If we don't sleep long enough, the breakdown of adenosine is insufficient, which means we start the day with excess of the neurotransmitter and reach the threshold earlier than normal. This makes us sleepy. Caffeine blocks adenosine receptors, allowing us to stay awake for longer. As soon as the caffeine is broken down by the liver, adenosine flows to the receptors and causes a "caffeine crash" - leaden tiredness that makes us reach for the next coffee straight away.

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Sleep cycles

While we sleep, our brain alternates between two sleep phases: non-REM sleep (without rapid eye movements) and REM sleep (rapid eye movements), with NREM dominating in the early stages and REM becoming more dominant in the later stages. This means that NREM phases are longer at the beginning of the night and then become shorter and shorter, while REM phases are short at the beginning and become longer and longer.

NREM sleep identifies and removes unnecessary nerve connections and memories in the brain and makes room for new ones. During NREM sleep, new memories are transferred from short-term to long-term memory. NREM promotes tissue renewal and repair through the release of growth hormones and immune activity is greater during NREM. Going to bed late shortens the NREM phases and thus influences how well the above-mentioned processes can be carried out. It can happen that the remaining time is not enough.

REM phases are the dream phases, and during REM sleep the brain is just as active as if we were awake. At this time, most muscles are paralyzed to prevent injury during dreaming. In REM, new neural connections are created and strengthened, utilizing the space freed up by the purge of NREM sleep. Waking up too early shortens REM sleep by 60 to 90 percent. REM sleep is needed to restore the mind rather than the body. REM facilitates learning and memory, is crucial for the development of our emotional IQ and enhances creativity as novel connections are made between unrelated pieces of information.

If we go to bed too late, we prevent sufficient NREM sleep, which reduces the opportunities for tissue repair. This can affect physical health. If we wake up too early, we disrupt REM sleep, which reduces opportunities for learning, memory, creativity and mental recovery. This affects our mental health.

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What is sleep good for?

Everyone has experiencedsleep deprivation, whether it's from late-night partying or after a long-haul flight to a different time zone, or because we've been cramming through the night before an exam. At some point, we reach the point where nothing works except lying down and sleeping. After a good night's sleep, we feel infinitely better and are ready for a new day. Everyone knows that we sleep to be able to muster energy. But what else does sleep do for us?

Cardiovascular disease: Short sleep has been associated with an increased risk of heart attack [ 1] and all-cause mortality [ 2]. People with cardiovascular disease often also suffer from sleep apnoea, where breathing stops several times during sleep, usually unnoticed by those affected. The lack of oxygen caused by the interrupted breathing in sleep apnoea leads to an increase in blood pressure in order to increase the oxygen content in the blood. If sleep apnoea is treated, blood pressure returns to normal. Those who suffer from sleep apnea are tired and exhausted during the day, and there is an increased risk of developing depression. (Young et al, 1993).

Digestive problems: There is no doubt that digestive complaints are linked to sleep disorders. People who suffer from insomnia report more digestive problems than people who sleep well (33.6% versus 9.2%). Conversely, people with digestive tract disorders report more insomnia than healthy people (55.4% versus 20%) (Taylor et al., 2007). It is not always easy to distinguish which came first: Did the insomnia make you sick or did the illness interfere with sleep?

Hormone fluctuations: Sleep helps regulate thyroid hormones, stress hormones and sex hormones. It affects insulin levels and the hormones leptin and ghrelin, which signal whether we are hungry or full. In this way, sleep affects our weight, stress management, mood, fertility and much more. Sleep deprivation is a significant risk factor for type 2 diabetes (T2D) that is often overlooked.

Mental and neurological health: Research has shown that almost all psychiatric disorders have some form of sleep disturbance. As explained above, adequate REM sleep is necessary for robust mental health, and shortening sleep - especially towards the end of the night - means shortening REM sleep. Sleep deprivation promotes anxiety disorders and depression, and suffering from anxiety disorders or depression exacerbates sleep deprivation - another vicious cycle.

Research suggests that increased production of certain proteins and their inadequate breakdown is one of the main causes of Alzheimer's disease. Sleep helps the body to eliminate excess proteins. This process takes time - about 7 hours - and can only take place during sleep. Anyone who thinks they can learn to get by on little sleep is mistaken. Protein breakdown from the brain cannot be accelerated. [3]

The effects of sleep on health do not end there. The immune system also needs sleep in order to function properly. Even allergies and inflammatory processes are associated with it. Since so many illnesses related to sleep or lack of sleep disrupt sleep or even make it impossible, the question always arises: which came first, the illness or the lack of sleep? Probably both, and both exacerbate each other.

Why sleep is so important for athletes

Actually, we all know that sleep is important. But why is it important? This infographic actually tells you everything you need to know about why sleep is especially important for athletes. But it's not just athletes who have to perform. We all perform immensely in our everyday lives! Here are 3 good reasons for getting enough sleep that don't just benefit athletes come:

1) Chronic sleep deprivation reduces sugar metabolism by 30-40%

2) Sleep deprivation increases reaction time

3) Sufficient sleep means that we can make decisions more quickly.

What can you do about sleep disorders?

The following tips for everyday life can help you to get better and more restful sleep:

• Make sure you don't fall asleep in front of the TV
• Make the bedroom a place of relaxation without TV, computer, noise and light
• The temperature in the bedroom should not be higher than 18 degrees Celsius
• Take a power nap in the afternoon, but for no longer than 20 minutes
• No heavy food or caffeinated drinks / alcohol before going to bed
• Do not look at the clock at night
• Don't go to bed with too many thoughts about the day. Sport or meditation can help.

We recommend our natural CBD oil for sleep disorders. Stress, anxiety disorders and depression are just some of the factors that can contribute to restless sleeping habits. CBD oil has properties that can help deal with these anxiety symptoms and relax the body and mind enough to rest. Another reason that CBD oil can help improve sleep is that the active ingredient cannabidiol can dock onto the endocannabinoid receptors in the brain and thus improve sleep stability. [4]

If you have problems with sleep, take a look at our latest newsletter, in which we provide tips for restful sleep.

Literature reference:Matthew Walker: Why we Sleep. Penguin, 2018

[1] Ayas NT, White DP, Manson JE, et al. (2003): A prospective study of sleep duration and coronary heart disease in women. Arch Intern Med. 2003;163(2):205-209.

[2] Kripke DF, Garfinkel L, Wingard DL, Klauber MR, Marler MR (2002): Mortality associated with sleep duration and insomnia. Arch Gen Psychiatry. 2002 Feb; 59(2):131-6.

[3] Ju YES, Lucey BP, Holtzman DM (2015): Sleep and Alzheimer disease pathology-a bidirectional relationship. Nat Rev Neurol. 2014 Feb; 10(2): 115-119.

[4] Zou S, Kumar U (2018): Cannabinoid Receptors and the Endocannabinoid System: Signaling and Function in the Central Nervous System. Int J Mol Sci. 2018 Mar; 19(3): 833.