Your internal body clock, AKA your circadian rhythm, responds to light and dark and regulates physical and mental processes that occur at different times.
Fascinatingly, you gut microbes work on a similar clock and have different functions during the day and at night. However, a lot of that depends on your own body clock and if you start going to bed at crazy times, it can disrupt your delicate community of microbes. If your circadian rhythm is out of whack from sleep deprivation, shift work or poor quality or erratic sleep, this can change the community of microbes living in your gut. The different functions bacteria have in the day and night also influence your own circadian rhythm (pretty smart eh?!).
Think of your microbes as being on shift work – when you go to sleep this signals for one shift to finish and another to start. Imagine if you never knew what time you were starting and finishing your day? You would be pretty confused, right?! There’s also research to suggest that some species (e.g. Bacteroidetes and Firmicutes), showed cyclical changes in abundance from day to night.
The first stage of sleep is non-rapid eye movement (NREM), there are 3 stages to this becoming progressively deeper. Waking up during this stage will make you feel a bit disorientated. This is then followed by rapid eye movement (REM) – where you dream. Each adult cycle lasts 1.5 hours and to feel refreshed, you need to go through all 4 stages, ideally 5-6 cycles per night.
After around 15 hours of being awake, you should start to feel ready to sleep again.
Between the ages of 18-65 you need 7-9 hours per day. What you need is likely to differ from one person to the next. Quality of sleep is also important; you could have 7-9 hours of total sleep but this could be disrupted sleep meaning you don’t go through all of the sleep cycles needed to help you feel refreshed.
It’s clear that making sure you sleep well is going to have a positive effect on your microbes and vice versa. Below are some simple steps you can take to help you get that circadian rhythm working as it should. REGULARITY is key.
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Liang, X., Bushman, F. D., & FitzGerald, G. A. (2015). Rhythmicity of the intestinal microbiota is regulated by gender and the host circadian clock. Proceedings of the National Academy of Sciences of the United States of America, 112(33), 10479–10484. https://doi.org/10.1073/pnas.1501305112
Liu, B., Lin, W., Chen, S., Xiang, T., Yang, Y., Yin, Y., Xu, G., Liu, Z., Liu, L., Pan, J., & Xie, L. (2019). Gut Microbiota as an Objective Measurement for Auxiliary Diagnosis of Insomnia Disorder. Frontiers in microbiology, 10, 1770. https://doi.org/10.3389/fmicb.2019.01770
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