We might remember countless nights as we stared at the clock and the sweet comfort of sleep eluded us as we did a mental countdown till our alarms rang. We knew the next day would be challenging because we missed out on the much-needed and recommended 7 to 9 hours of sleep . But being groggy and grumpy isn't the only side-effect that should concern us. Sleep deprivation over time can lead to many problems like cardiovascular diseases, obesity, immunodeficiency, mental health disorders, and it can also have a detrimental effect on our gastrointestinal health [2, 3].
The connection between our sleep and digestive system is not something that’s been explored at a larger scale, however, it is something that’s worth knowing about; this article is going to do just that!
Read on to understand how our sleep and digestive health are connected, the impact that sleep deprivation can have on our gastrointestinal health and things you can do to improve your sleep and digestive system.
Let’s start with understanding the connection between the two:
What happens to our digestive system when we sleep?
Our digestive system carries out the monumental task of digesting our food. It breaks our food down for the rest of our body to use and stops any harmful and unnecessary elements from entering the body any further. This is a continuous process that continues even when we are sleeping, albeit at a slower pace .
When we sleep, our body also repairs all the regular wear-and-tear it’s experienced during the day - this applies to our digestive system as well. During our sleep, our digestive system is busy repairing and rebuilding tissues in our gut, while also growing the good gut bacteria that aid our digestive processes [4, 5].
In simple words, our sleep assists the smooth functioning of our digestive system through rest and repair; inversely, lack of sleep can have a negative impact on this.
Here’s what happens to our digestive system when we don’t get enough sleep:
How sleep deprivation affects our digestive system
1. Increases inflammation in the gut lining
Our gut, or the gastrointestinal tract, consists of the entire tube that starts from our mouth and ends at our anus. Sleep deprivation is usually associated with an increase in the pro-inflammatory molecules in our gut, which may lead to inflammation along its lining [6, 7]. This may cause gastrointestinal symptoms such as nausea and bloating, and can slow down our gastric emptying (the process by which the stomach contents are moved into the small intestine) [8, 9].
2. Causes hormonal disturbances that increase cravings
There are two hormones that send signals to our brains when it comes to our food - ghrelin (makes us feel hungry) and leptin (signals that we are full) .
Lack of sleep can lead to an imbalance in these hormones, making us crave more sugary foods, which, in large amounts, can contribute to an overgrowth of harmful bacteria in the gut, affecting our gut health by causing bloating, diarrhoea, abdominal pain, and nausea [11, 12, 13].
3. Increases intestinal permeability, leading to gut-related issues
Sleep deprivation can cause a rise in another hormone called cortisol (our primary stress hormone). Increased cortisol levels lead to intestinal permeability (also known as a leaky gut), where food and toxins can pass through the intestinal lining into the bloodstream (which is otherwise restricted in a healthy gut) [14, 15].
When this happens, we can experience issues like bloating, stomach pain and changes in the gut microbiome.
4. Causes bowel muscle fatigue, leading to constipation
Apart from the lining of our gut and hormones, lack of sleep can also trigger a few problems with our muscles in the digestive tract.
Lack of sleep can hamper our bowel's ability to rest and recuperate, further leading to bowel muscle fatigue that can cause reduced bowel movement and function. We usually feel constipated when this happens [8, 16].
Interestingly, many women experience low sleep quality and constipation while on their periods, but very few know that both are actually inter-connected.
5. Rectal distension
Another muscle affected by lack of sleep is the one in our rectum (a muscular tube at the end of the large intestine and above the anus that stores faeces). Sleep deprivation can cause increased stretching of the rectal wall causing rectal distension - where instead of sensing fullness and excreting normally, our rectum expands to store more waste matter and cannot excrete (affecting bowel movement) .
In case you’re struggling with any of the symptoms mentioned above (or even diarrhoea, gas, cramping and abdominal pain), in addition to consulting your doctor, it’s also a good idea to consider the consistency of your sleep schedule and how that might play a role here.
Interestingly, this connection between our sleep and digestive system also gives us an opportunity to improve them. Here are a few things we can do to improve both simultaneously:
How can we improve our sleep and digestive health?
1. Avoid overeating before bedtime
Research suggests that any large meals should be consumed 2-3 hours before we sleep. Our digestive system does a lot of resting and healing while we sleep, and overloading it with a heavy meal can disrupt our sleep while also interfering with digestion and increasing the risk of heartburn .
2. Avoid sleeping in positions that compress our stomach
The best position to sleep is usually the one that promotes a healthy spinal alignment from our hips all the way to our head [19, 20].
Sleeping on our back with our head supported by a wedge pillow is what most doctors recommend, but sleeping on our side also doesn't hamper our digestive system in any way. We should avoid sleeping on our stomachs because when we do that, we can compress the organs of our digestive system.
3. Manage stress
It is difficult to sleep when we are stressed, and to top that, the stress hormone also affects our digestion. So it becomes really important to ease stress. Taking a moment to breathe, relax and do nothing has shown to help. Activities like meditation, exercise, and listening to music can help us manage our stress. It’s all about finding and practising a suitable activity that makes you feel relaxed and at ease .
4. Exercise regularly
First things first, exercise helps us reduce stress . In addition, it also aids sleep by reducing the time it takes us to fall asleep and increasing the amount of time we spend in deep sleep (non-REM). Physical activity may also improve gastric emptying and lowering the risk of colon cancer [23, 24, 25]. Exercising is always a win-win for our health!
5. Get the right nutrition
Sleep quality and gut health both benefit from probiotic foods (like yoghurt, buttermilk), fermented foods (like idlis, dosas and dhoklas), and prebiotic food (like garlic onion, wheat, barley, tomato, and beans) as they promote the growth of healthy gut bacteria and improve nutrient absorption [26, 27]. Incorporating fibre-rich foods like broccoli, carrots, berries, barley, nuts, and legumes in our diet can also help suppress the hormone ghrelin in our system, reducing the absorption of sugar into the bloodstream, leading to limited growth of harmful bacteria in our gut [28, 29]. Research results show that fibre intake predicted more time spent in the stage of deep, slow-wave sleep (SWS) - the most restorative sleep stage that is associated with superior sleep quality .
6. Get the right amount of hydration
All posts about wellness will share that we need to drink water, but what they miss is that it is necessary to find the right balance of fluid intake. Drinking 2 - 3 litres of water every day may contribute to better sleep and help you digest food, absorb nutrients and get rid of the waste but drinking too much water may cause excess urination that may lead to sleep interruptions in some people .
The effects of sleep deprivation go beyond irritability and grogginess especially when we are talking about our digestive system. However, by making some changes (as mentioned above) in our daily routine, it is definitely possible to achieve a good sleep routine that promotes better digestive health.
If you have any feedback or questions about the information in this article, leave a comment below – we'd love to hear from you!
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