January 26, 2024

So, how do you sleep?

Explore the vital connection between sleep and your gut health

So, how do you sleep?

"I've always slept well, but lately I just can't get any rest ..."

There is hardly a conversation among friends and colleagues in which the topic of sleep, or rather difficulties with sleeping, does not come up at some point. Probably because we notice relatively quickly when we have slept too little or poorly and clearly notice the disruptions in our daily routine.
Internationally, 1/3 of all people have difficulty falling asleep or staying asleep from time to time (1).
Chronic insomnia affects around 10% of all adults in Europe (2).

Restful sleep is so important for our body!

It is the most important regeneration, repair and processing program for humans and is therefore VITAL.
In the SHORT TERM, sleep has an impact on our mental (ability to concentrate and make decisions, learning, memory, ability to react, willingness to take risks, etc.) and physical performance.
In the LONG TERM, the quality of our sleep influences our immune system, our metabolism, our cardiovascular system and of course our brain and psyche. As a result, there is a higher susceptibility to infection coupled with an increased risk of diabetes, hypertension, obesity, cardiovascular diseases, anxiety disorders and depression. In addition, pain sensitivity also increases (3, 4).

Our body can compensate for ONE sleepless night

We all know this: you toss and turn restlessly, but you just can't “switch” from awake to sleep mode. Or you wake up during the night and have a hard time getting back to sleep. If there is a reason for this (eating too heavy in the evening, an unpleasant experience during the day, an upcoming, worrying appointment, etc.) and if it stays for one or at most a few nights, our body can compensate for it and regenerate itself again. However, if the sleepless night repeats itself more often, it affects numerous processes in our body and we slip into a manifest sleep disorder with all its consequences for body AND mind.

Sleep disorders

Not being able to fall asleep, waking up and not being able to go back to sleep (e.g. racing thoughts), overall sleeping too short and not restfully in combination with daytime tiredness and reduced performance. And all this despite the fact that the environment and time are right for a good night's sleep.
If the problems last 3 times a week for more than 1 month, it is considered a sleep disorder. If it lasts more than 3 months, the criteria for insomnia are met (5).

Sleep disorders, deviations from normal sleep patterns, such as insomnia, sleep apnea, narcolepsy or restless leg syndrome, affect the quality of life and performance of numerous people around the world every day. However, as already mentioned above, they not only have a direct impact on health, but also on the economy and the health system: accidents and sick leave occur more frequently due to lack of concentration. Reduced performance or illnesses due to sleep disorders increase the number of doctor visits, hospital stays, treatment costs and early retirement (2).

Did you know?

A lack of sleep affects our feeling of hunger and therefore also our WEIGHT MANAGEMENT:
* Leptin (“satiety hormone”) decreases, ghrelin (“hunger hormone”) increases, leading to increased food intake.
* Impaired glucose tolerance causes blood sugar levels to rise and fall rapidly, leading to hunger or cravings.
* Increased orexin secretion promotes alertness and the desire for food, while the feeling of satiety decreases.
There is evidence that orexin is linked to the reward system in the brain and leads to a preference for certain foods (often high in sugar and fat).

Nighttime snacking due to insomnia contributes to weight gain. And excessive weight gain, in turn, increases the risk of metabolic syndrome and sleep disorders, such as obstructive sleep apnea (6). Conversely, restful sleep makes it easier for us to regulate our weight (7).

Sleep problems? First, investigate the cause, then treat!

IN ADVANCE: The need for sleep varies.
In addition to age, chronobiology also plays a role. Some people are early risers, while others only get into top form in the evening.
AND: Duration of sleep should not automatically be equated with quality of sleep. The longer doesn't mean the better.
What is crucial is that we go through the various sleep phases completely and feel well-rested and productive the next day, and actually are. Adults are recommended to get between 7 and 9 hours of sleep/night.
As said, it must be determined on an individual basis how much sleep is actually necessary (8).

Those affected by sleep disorders often try to improve their sleep with home remedies. If these do not have the desired effect, medication is often used to help. If this happens without prior consultation with a doctor, a vicious circle can quickly begin because they should only be taken for a limited time so that dependence and/or a chronic sleep disorder does not develop.

Researching the causes is primarily about finding out whether there are physical or psychological causes or whether the sleep problems are associated with the consumption of various substances.
A sleep diary can very well establish connections between medication intake, consumption of alcoholic and/or caffeinated drinks, drugs, pain, illnesses, stress, stressful situations, etc. and sleep problems. Various apps can also be helpful. Based on this, clues can be found in a conversation with the doctor, which is supplemented by a physical examination and a blood analysis. If nocturnal breathing disorders or restless legs syndrome are suspected as the cause, an examination in a sleep laboratory makes sense (9).

Causes of sleep disorders

The following areas can be roughly distinguished
* environmental
* physical
* psychical
* behavioral

Room temperature, light sources and noise, for example, play a role in the environment. Artificial light slows down the production of melatonin (“sleep hormone”) and makes it difficult to fall asleep. Physiological criteria include our level of physical activity during the day, hormonal changes, illnesses, drug interactions, pain. Psychologically, stress, anxiety or mental illnesses such as depression have a high impact by increasing cortisol release. In terms of behavior, social obligations and dynamics should be mentioned, but also shift work, caffeine consumption, 24-hour availability and excessive screen time. In addition, signals of tiredness are often ignored and the right moment is simply overlooked (4, 8).

Last but not least: The gut microbiome, which is out of balance, also influences our sleep quality ...

Gut microbiome & sleep

The gut microbiome is connected via the gut microbiome-brain axis and sends signals in both directions. Among other things, the microbiome promotes the release of various neurotransmitters (dopamine, serotonin, GABA) and neuromodulators (e.g. SCFAs) and thus plays an important role in mood and sleep. If dysbiosis occurs due to stress, this can trigger or worsen sleep disorders. Sleep disorders, in turn, can increase anxiety and increase stress levels. A negative cycle ...

In addition, unhealthy sleeping habits (jet lag, “social” jet lag due to obligations, etc.) lead to an interference with the circadian rhythm and, as a result, to a decrease in bacterial diversity. This impairs the functionality of the gut microbiome and affects our immune system (70-80% of our immune cells are in the intestine) and our metabolism. Dysbiosis increases the risk of leaky gut and, as a result, inflammation, atherosclerotic processes and cardiovascular diseases (10, 11, 12).

Up to 90% of serotonin, the precursor to melatonin (“sleep hormone”), is produced in the gut, provided the intestinal microbiome is in balance. It acts as a hormone and neurotransmitter and thus has an impact on mood, pain perception, appetite and eating behavior. It also stimulates intestinal motility (10, 13). A balanced gut microbiome has a direct effect on sleep behavior and also appears to have a positive influence on the sensation of pain, making it easier to fall asleep or stay asleep (14, 15, 16). Effects on mental health, such as depression, have also been shown (13).

This shows how important it is to start on both sides: gut microbiome & sleep!

The good news – most sleep problems are preventable or treatable!

It is important to find individual solutions and establish sleep-promoting habits through consistent behavioral changes:
* sleep hygiene (cool, darkened, quiet room, if possible without electronic devices, good mattress)
* sleep routine (regularity to stabilize the sleep-wake rhythm)
* evening rituals (to make it easier for the brain to transition from awake to sleep mode)
* relaxation techniques (breathing exercises, yoga, etc.)
* if napping, then for a limited time (20 minutes) and before 3:00 p.m
* enjoy 30 minutes of sunlight during the day
* exercise regularly, but max. 2-3 hours before going to bed
* avoid coffee and nicotine in the evening
* little alcohol (it makes you fall asleep quickly, but disrupts the sleep phases)
* light dinner and possibly herbal tea (lavender, lemon balm, valerian, etc.)


If insomnia is diagnosed, CBT (cognitive behavioral therapy - app and/or therapist) is the treatment of choice.
In addition, medications prescribed by a doctor can be used for a limited time (9).

In general, a lot lies in our own hands ...

So, look at your gut microbiome, enable your brain to switch from waking to sleeping mode through an evening ritual, have a restful sleep and start the new day in a good mood, creatively and with lots of strength!
After a night of restful sleep, we are not only physically fitter, but also cognitively better equipped than people who haven't had enough sleep. In addition, well-rested people behave more helpfully towards others and are more creative (11).

Seems the world would be a better place if everyone slept well ...


(1)    Haitham Jahrami et al. (2021): Sleep problems during the COVID-19 pandemic by population: a systematic review and meta-analysis, in: Journal of Clinical Sleep Medicine 17(2):299-313.
(2)    Jason Ellis et al. (2023): Chronic Insomnia Disorder across Europe: Expert Opinion on Challenges and Opportunities to Improve Care, in: Healthcare 11(5):716. doi:10.3390/healthcare11050716.
(3)    Kannan Ramar et al. (2021): Sleep is essential to health: an American Academy of Sleep Medicine position statement, in: Journal of Clinical Sleep Medicine 17(10):2115-2119.
(4)    Kathy L. Nelson et al. (2022): Sleep quality: An evolutionary concept analysis, in: Nurs Forum 57: 144-151.
(5)    Milena K Pavlova, Véronique Latreille (2019): Sleep Disorders, in: The American Journal of Medicine 132(3):292-299.
(6)    Chenzhao Ding et al. (2018): Sleep and Obesity, in: Journal of Obesity & Metabolic Syndrome 27:4-24.
(7)    Esra Tasali et al. (2022): Effect of Sleep Extension on Objectively Assessed Energy Intake Among Adults With Overweight in Real-life Settings, in: JAMA Internal Medicine; 182(4):365-374. doi: 10.1001/jamainternmed.2021.8098.
(8)    Jean-Philippe Chaput et al. (2018): Sleeping hours: what is the ideal number and how does age impact this?, in: Nature and Science of Sleep 10: 421-430.
(9)    Charles M. Morin et al. (2023): World sleep society international sleep medicine guidelines position statement endorsement of “behavioral and psychological treatments for chronic insomnia disorder in adults: An American Academy of sleep medicine clinical practice guidelines, in: Sleep Medicine 109:164-169.
(10)  Bruna Neroni et al. (2021): Relationship between sleep disorders and gut dysbiosis: what affects what?, in: Sleep Medicine; 87:1-7.
(11)   Robert P. Smith et al. (2019): Gut microbiome diversity is associated with sleep physiology in humans, in: PLoS ONE 14(10): e0222394.
(12)  Zhe Wang et al. (2022): The microbiota-gut-brain axis in sleep disorders, in: Sleep Medicine Reviews 65 https://doi.org/10.1016/j.smrv.2022.101691.
(13)  Angelica Varesi et al. (2023): The brain-gut-microbiota interplay in depression: A key to design innovative therapeutic approaches, in: Pharmacological Research 192, https://doi.org/10.16/j.phrs.2023.106799.
(14)  Amir Minerbi, Shiqian Shen (2022): Gut Microbiome in Anesthesiology and Pain Medicine, in: Anesthesiology 137:93-108.
(15)  Maxim B. Freidin et al. (2021): An association between chronic widespread pain and the gut microbiome, in: Rheumatology 60:3727-3737.
(16)  Klaudia Ustianowska et al. (2022): The Role of the Human Microbiome in the Pathogenesis of Pain, in: International Journal of Molecular Science 23, https://doi.org/103390/ijms232113267.