Your body is teeming with little clocks. In fact, it’s thought that nearly every cell in the body has its own little clock. The master clock (the ‘head timekeeper’) is located inside the brain – it keeps all the little clocks in rhythm so that bodily processes remain in sync.
The master clock keeps to a 24-hour sleep-wake cycle by following the 24-hour light-dark cycle on Earth - called your circadian rhythm.
Your gut microbiome follows a 24-hour cycle too - studies have also shown that the composition and function of gut microbes rhythmically change throughout the day.
Why sleep matters
Humans have evolved over millions of years to need a certain amount of sleep – around 7-9 hours every night. On average, you spend one third of your life sleeping. This might sound like a lot, but there is very good reason why sleep should be a non-negotiable activity.
Every part of the body is positively affected when you get enough sleep, and every part of the body is negatively affected when you don’t. As sleep expert Matthew Walker says, ‘the shorter you sleep, the shorter your life’.
Despite the necessity for sleep, sleep less than the recommended 7-9 hours. Shift work can also compromise quality and quantity of sleep. Currently, worldwide are shift workers.
Modern life can negatively affect sleep too. The increased use of technological devices, daily stressors, travel across time zones, and other lifestyle factors such as alcohol consumption and lack of exercise have all been linked to disturbed sleep.
The benefits of sleep
Sleeping gives the brain the valuable opportunity to undergo a range of recover, restore, and repair activities that are essential for maintaining health and reducing the risk of ill health. For example, sleep allows flushing out the brain’s clearance system so waste that has built-up can be efficiently removed.
Sleep also helps with…
- learning and embedding memories in your brain
- problem solving and decision making
- creativity and generating ideas
- regulating emotions and dealing with stress
- enhancing immune defence and recovery from illness
- improving responses to vaccinations
- maintenance of metabolic health including regulation of hormones, blood pressure, and glucose control
- keeping your gut microbiome diverse
How the gut microbiome affects sleep
The gut microbiome produces thousands of different compounds. It’s well known that some of these can directly and indirectly affect sleep.
For example, some gut microbes can directly convert tryptophan (amino acid found in many foods) to serotonin and melatonin. Both play key roles in sleep regulation. Other compounds such as short chain fatty acids (SCFAs) may influence sleep by helping to regulate the little clocks throughout the body. SCFAs might also affect sleep durationin humans.
What’s more, sleep has been shown to impact gut microbiome diversity with increased diversity linked to longer sleep times
A diverse gut microbiome is one that contains a wide range of different microbes. Diversity is thought to be a hallmark of health and important for a stable and resilient gut microbiome.
Summary
Sleep plays an essential role in the health of your brain and the rest of the body.
Research also suggests the quality and quantity of your sleep can affect the gut microbiome and vice versa.
To encourage a good night’s sleep, try some of these tips.
Sources
Circadian rhythms, gut microbiota, and diet: Possible implications for health. Nutrition, Metabolism and Cardiovascular Diseases. (2023). Link.
Digital circadian and sleep health in individual hospital shift workers: A cross sectional telemonitoring study. EBioMedicine. (2022). Link.
Gut microbiome diversity is associated with sleep physiology in humans. PLos One. (2019). Link.
Shorter sleep time relates to lower human defensin 5 secretion and compositional disturbance of the intestinal microbiota accompanied by decreased short-chain fatty acid production. Gut Microbes. (2023). Link.
Sleep characteristics across the lifespan in 1.1 million people from the Netherlands, United Kingdom and United States: a systematic review and meta-analysis. Nature Human Behaviour. (2020). Link.
The role of gut microbiome in sleep quality and health: dietary strategies for microbiota support. Nutrients. (2024). Link.
