Poor sleep and the ageing gut: What does the science say?

We sleep for 26 years of our lives. While such a fundamental part of our daily lives, the scientific community still debates as to the evolutionary purpose of sleep. One ruling school of thought supports the theory that sleep is nature’s way of making sure we don’t overexert ourselves by reducing the energy demand we would expend while awake. Another group supports that the main role of sleep is to “clean” out our system and get rid of waste our bodies produce via biological processes throughout the day. Sleep touches every aspect of human health, although we are yet to decipher all the restorative powers it has to offer.?

Quality of sleep decreases as we age?

Think of any older relatives you may have, such as your parents. Do you see any differences in your sleeping patterns with theirs? We know for a fact that our sleep cycles become shorter and we inevitably sacrifice a few stages to get as much “deep sleep” as possible. This is where the restorative effects of sleep take place. The changing architecture of sleep inherently affects a number of other systems in our body.?

Other than the more visible fatigue and crankiness in those who sleep poorly, there are many hidden ways sleep affects our health. You may have seen many fitness gurus on social media preaching the importance of sleeping enough to boost your “gains”. They are actually right in many ways. Good sleep is known to preserve muscle mass, mostly through hormonal pathways, although there could be other mechanisms we may still need to uncover.?

How your sleeping patterns could affect your gut?

The paper we recently published summarizes a lot of evidence on how sleep affects gut bacteria. You may have heard about your gut bacteria mostly through yoghurt commercials and how they help your gut bacteria. It may very well be that sleep and yoghurt affect similar bacteria in your gut.?

You can think of your gut as a garden with many different species of flowers. Each flower type would represent a different bacterial family. While the role of these bacteria is not necessarily to smell as good as these flowers, they mostly provide our body with compounds that help regulate our immune system and provide us energy overall. However, like in any garden, there are also weeds that could pop up. These weeds are the “bad” bacteria in our gut that could disrupt the way our body functions. As long as we keep these weeds or “bad” bacteria in check and make sure we have more of the “good” bacteria, we have nothing to worry about.?

The scientific community is slowly starting to realize that many diseases affect our gut bacteria and allow the bad ones to multiply. This would in turn aggravate the situation by having these bad bacteria further disrupt the beneficial biological processes in our body.?

In our review, the majority of studies show that different bacteria can thrive depending on how much and how well we sleep. While there is no definitive answer as to which specific bacteria increase with sleep, a few studies suggest that the amount of bad bacteria could actually increase if we sleep poorly as we do when we grow older.?

Why are bad bacteria bad and how they can affect our muscle

As I mentioned earlier, these bad bacteria disrupt the way our bodies work. To understand their effect, we first have to talk about the lining of our gut. The lining is very much an array of cells that are tightly connected much like a chain. In a diseased state, the integrity of the lining could be compromised and actually end up producing cracks in our chain. Biologically-speaking, our cells would not be as tight as they were before, leaving gaps between them.?

These bad bacteria are capable of producing an inflammatory compound that would usually not affect us if it remained in the gut. However, if these compounds fly through the cracks in our gut lining, they could enter our bloodstream and trigger our body’s immune system. This generalized inflammation throughout our body would theoretically lead to “muscle lockdown” where it would no longer respond to growth signals. After some time without stimulation, our muscle proteins would start breaking down and losing both mass and strength, thus affecting our famous “gains”.?

You may be wondering what this has to do with ageing. There is actually a fountain of evidence showing that ageing leads to a state of generalized inflammation in the body due to many biologically-complex reasons. Because of this, older adults are known to endure a naturally-occurring condition known as sarcopenia, in which we constantly lose muscle mass and strength due to continuous inflammation in our bodies.?

While the specific role of the gut and the resulting effect on muscle mass in older adults is not experimentally backed up, we found a collection of experiments looking into a combination of sleep, gut bacteria, inflammation, or ageing in humans. Generally the papers seem to point towards different bad bacteria that could be associated with age. In our paper, we weave through all this scientific evidence to provide a solid mechanism in which these gut bacteria could play a role in the development of the infamous sarcopenia. Ideally more experiments will pick up on this potential mechanism to test out in the future.?

Afraid your bad bacteria could take over anytime??

Fret not. These bad bacteria are usually kept in check in an average healthy individual. It is very important to encourage our good bacteria to multiply by consuming a well-balanced diet with an abundance of nutrients. Actually, there is also growing evidence to show that exercise could also boost these healthy bacteria. You don’t have to be an elite athlete to help your good bacteria flourish. You can easily muster up three to five moderate workouts a week to already see the benefits!?

Take-home messages

To summarize the above, there are two key points I want you to remember. The first is that your gut bacteria could play a bigger role in your health than you think, so make sure you do all you can to encourage your good bacteria to grow! The second is to ensure good sleep hygiene to optimize the good bacteria. The evidence doesn’t lie and your gut will thank you for it!

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Sources

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Lunenfeld, B., & Stratton, P. (2013). The clinical consequences of an ageing world and preventive strategies. Best Practice & Research. Clinical Obstetrics & Gynaecology, 27(5), 643. https://doi.org/10.1016/J.BPOBGYN.2013.02.005?

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Walker, M. (2018). Why we sleep. Penguin Books.