Your eyes are bleary, your brain is foggy, and your limbs are heavy. You’re laying in bed and everything’s saying it’s ready for sleep. There’s just one problem: your digestion.
Whether you’ve got acid reflux, bloating, or just a loud and rumbling stomach, digestion — even when it’s going well — can easily keep you up late into the night.
While the best fix is to give your body enough time to digest before bed, the next-best fix is sleeping on the “right” side, which, ironically, may not be the right side at all.
Below, we’ll dive into the best side to sleep on for digestion and other science-backed advice for making sure your nighttime digestion doesn’t impact your sleep. We’ll also share how the RISE app can help on your journey to better sleep and better digestion.
Want to maximize your digestion? Here’s the best position to be in post-meal.
The best side to sleep on for digestion isn’t a side at all: it’s actually standing or sitting up.
Don’t worry, we’re not suggesting you sleep sitting up. Instead, give your body two to three hours in between your final meal and going to sleep so it can get a head start on digestion.
When we’re horizontal, gravity can’t help food move through our digestive systems, so it’s digested more slowly. Your digestive system slows down during sleep, too, and there’s an increased risk of heartburn when you’re laying down.
Your stomach produces gastric acid to digest the food you’ve just eaten. But if you lay down shortly after eating, this acid can easily travel up your esophagus and stay there for longer. This can cause pain and damage if it happens regularly.
When you do go to sleep, sleeping on your left may be the best side when it comes to digestion. When you’re lying on your left side, gravity can help waste travel from your small intestine to your large intestine.
Left-side sleeping may help with digestive issues, too. A 2022 study found sleeping on the left-hand side helped those with gastroesophageal reflux disease (GERD) have more reflux-free nights. Another study found sleeping on the left or sleeping with the head elevated reduced GERD symptoms.
Left-side sleeping is also the best side for:
And sleeping on either side can have health benefits like:
Try placing a pillow between your legs to keep your spine aligned. If you find you get shoulder pain from lying on one side, you can switch throughout the night.
Side sleepers may be best for digestion in general, but not when things are going wrong. Right-side sleeping has been found to make reflux worse in those who suffer from it. It’s not entirely clear why, but it’s thought it could be because the stomach is lower than your esophagus when you’re lying on your left, making it harder for stomach acid to rise up.
Beyond digestion, right-side sleeping may be best for those with heart failure, but more research needs to be done to confirm.
If your sleeping habits involve sprawling out on your back, you may want to think again. Back sleeping can increase how much acid reflux you get as stomach acid can more easily travel up the esophagus.
Back sleeping may be better if you want to prevent wrinkles, as your skin won’t be squashed against your pillow, when recovering from surgery or a c-section, or if you suffer from joint pain and find side sleeping too painful.
If you do sleep on your back, consider placing a pillow under your knees to keep your spine aligned and raising your head if you suffer from acid reflux. A supportive pillow is important even if you don’t have reflux to avoid neck pain.
It’s bad news for stomach sleepers. There’s not much evidence that this is the best position for digestion — or anything else.
Front sleeping can cause acid reflux, it puts pressure on your neck and spine, and it can be painful if you’re suffering from indigestion, bloating, cramps, or general stomach pain, as you’re putting weight on your stomach.
The one time when sleeping on your stomach is best? When it’s a choice between that and missing out on sleep. If you can’t get a good night’s sleep in any other position, use a thin pillow or no pillow at all to reduce neck pain and keep your spine aligned.
We’ve covered more about sleeping without a pillow and proper pillow position for sleeping here.
Most of the time, the best sleep position is the one you find most comfortable and the one that helps you fall asleep.
Unless you’ve got a specific health issue to think about — like GERD or sleep apnea — or you’re pregnant, there isn’t much definitive research to say which sleep position is best.
We say, sleep in the position that’s most comfortable for you and instead focus on leaving enough time between dinner and bedtime for digestion (aim for two to three hours). After all, even left-side sleeping can’t stop digestive issues from keeping you up if you have a large, rich meal and then head straight to bed.
Want to dive in deeper? We’ve covered the best side to sleep on here, and the sleeping positions to lose weight here.
Beyond your position, your sleep can impact your digestion in other ways.
It doesn’t matter which position you sleep in if you’re not getting enough sleep overall. When we don’t meet our sleep need — the genetically determined number of hours of sleep we need each night — our digestion suffers.
Not getting enough sleep has been linked to many gastrointestinal diseases, and poor sleep can make their symptoms worse. These health problems include:
Poor sleep — including having trouble falling asleep and waking up during the night — has also been associated with upper and lower GI symptoms. It increases your odds of upper abdominal pain, nausea, reflux symptoms, and constipation.
When you’re sleep deprived, levels of the stress hormone cortisol spike, which can lead to weight gain, overeating, and more sleep loss — which all affect digestion. And stress itself can cause stomach issues like constipation, diarrhea, indigestion, and IBS.
Not getting enough sleep can also make you feel pain more intensely. So, if your stomach hurts in the morning, for example, sleep deprivation may be adding to this discomfort.
Sleep loss can lower your immune system, which may increase inflammation in the bowel and cause gastrointestinal symptoms.
And finally, when you’re sleep deprived, you’re more likely to reach for processed junk foods or indulge in a late-night snack craving. Your hunger hormones — ghrelin and leptin — are thrown out of whack, meaning you’re more likely to overeat. All this can cause indigestion and other digestive issues.
The effects of sleep deprivation go beyond digestion, though. Not getting enough shut-eye ups our odds of everything from heart disease to mental health conditions and all-cause mortality — not to mention general sleepiness during the day.
Sleep deprivation looks different for all of us. The RISE app can work out your individual sleep need and how much sleep debt you’re carrying. Sleep debt is the running total of how much sleep you owe your body. We measure this over your last 14 nights.
To keep your digestion running smoothly, aim to keep your sleep debt low overall. We say aim for five hours or less for optimum health.
RISE users on iOS 1.202 and above can click here to view their sleep need.
RISE users on iOS 1.202 and above can click here to view their sleep debt.
Beyond how much sleep you get, when you sleep and eat makes a difference to your digestion. This is where your circadian rhythm comes in.
Your circadian rhythm is your body’s roughly 24-hour biological clock. But there’s more than one clock to think about.
There’s your master clock located in your brain called the suprachiasmatic nucleus (SCN). This clock dictates your sleep-wake cycle, among other things. But there are also clocks in almost every tissue and organ system. These are known as peripheral clocks.
While your master clock communicates with your peripheral clocks, they can all get out of sync with each other.
To make things a little more complicated, your digestive system runs on several circadian rhythms, including one that dictates when you produce saliva, one for stomach acid secretion, and one that controls when damaged cells in your stomach lining are replaced.
In fact, the gut’s clocks are so complex, they can take the longest to adjust to jet lag or any other disruption to your circadian rhythm.
Why is your circadian rhythm important for digestion? When you sleep at odd times, you throw your circadian rhythms — including the ones in your gut — out of whack. This can happen with meal timing, too.
When you eat at roughly the same time each day, your gut knows when to expect food and it’s standing by ready to digest everything. When you eat when your gut isn’t expecting you to — like in the middle of the night — you may find you get digestive issues as the food can’t be digested properly.
It’s not just eating at night, though. Eating close to bedtime can cause excess stomach acid — we produce more of this at night. And as we don’t produce as much saliva late at night — our bodies aren’t expecting us to eat after all — this acid can’t be neutralized and it can lead to acid reflux, no matter what side you’re sleeping on.
Your clocks can get out of sync at different rates, too. One study looked at participants who underwent a three-day simulated night-shift schedule. The results showed their master clocks shifted by about two hours, but some metabolites used to measure peripheral clocks had shifted by a whopping 12 hours — essentially inversing completely.
In non-science speak, that means your gut could be hours out of sync with your master clock and the outside world. You might eat a meal, but your digestion isn’t ready for it at all, causing digestive issues and sleep problems.
Sleeping and eating in sync with your circadian rhythms can stop this from happening, though. A 2021 study found nighttime eating led to misalignment between the master clock and peripheral clocks, whereas daytime eating prevented this.
The RISE app can predict your circadian rhythm each day, showing you when your body naturally wants to wake up and go to sleep. You can then see if your sleep and meals match up with this, and make changes to your daily routine if they don’t.
RISE users on iOS 1.202 and above can click here to see their circadian rhythm on the Energy screen.
The link between sleep and digestion goes both ways. Your sleep can affect your digestion, but your digestion can also affect your sleep, creating a vicious circle if you get it wrong.
If you’ve got a digestive issue like GERD or heartburn, your sleep can easily be impacted. Among those with heartburn, 79% get symptoms at night. And among those, 63% say it affects their ability to sleep. And the risk of GERD symptoms in those with insomnia is three times higher than in those with no sleep problems.
Reflux may be associated with wheezing, chronic cough, and sleep apnea — which will all cut into your sleep time.
Of course, even when digestion is going well, what you eat can play a role in how you sleep. Sugary snacks before bed — hello, late-night desserts — can spike your insulin and cortisol, keeping you awake. Anything with caffeine or alcohol in can also keep you up or wake you up during the night. If your body’s still digesting these items, they could cut into your sleep.
Research shows high-caloric food intake 30 to 60 minutes before bed may increase sleep latency (how long it takes to fall asleep) in women. And high fat and carb foods may do the same.
Want to know what to eat to help you drift off? We’ve covered the best foods for sleep here.
Once you do fall asleep, digestion can wake you up during the night. Digestion can lower your arousal threshold, meaning you wake up more easily. This means anything from a noise in your house to your afternoon coffee could wake you up in the night.
The closer you eat to bedtime, the worse this could be. A 2021 study found eating or drinking within an hour of bedtime was associated with increased wakefulness during the night.
Digestive issues can also be to blame. People with stomach problems like indigestion or IBS report sleep disturbances more often than healthy people.
During sleep, your esophagus becomes more susceptible to gastric acid injury as you’re swallowing less and producing less saliva. This leads to more acid reflux, and the pain of this could wake you up.
There’s also a link between GERD and sleep apnea, a sleep disorder that causes you to stop breathing temporarily throughout the night. It’s thought 58% to 62% of people with sleep apnea have GERD.
There’s a further link between a higher body mass index (BMI) and increased episodes of GERD. But obesity puts you at a higher risk of sleep apnea. And all the sleep loss from GERD and sleep apnea can up your odds of weight gain.
Again, what you eat makes a difference, too. One study found a diet low in fiber and high in saturated fat and sugar was associated with waking up more often during the night. And if you enjoy a nightcap, alcohol can cause you to wake up during the night, too.
Even if you manage to fall and stay asleep after a meal, your sleep may not be as restorative as it could have been.
If you go to sleep when your body’s busy digesting, blood can get diverted from your brain down to your gut to help get the job done. But this means your brain has fewer resources to do the repair and waste removal it needs to do during sleep.
Research shows low-fiber and high-saturated fat and sugar diets are linked to lighter, less restorative sleep. More fiber, on the other hand, is linked to more deep sleep.
Plus, digestive issues aren’t exactly a recipe for a restful night’s sleep. For example, IBS is linked to poor sleep. More than 57% of IBS patients report abdominal pain and discomfort that wakes them up during the night, and restless leg syndrome is more common in those with IBS. Those with IBS may also spend more time in the rapid-eye-movement stage of sleep (also known as REM sleep), which can include more arousals and colon movements, which may disturb sleep. Sleep disturbances for those with IBS may additionally or alternatively be related to a hyperresponsiveness or exaggerated reaction to normal stimuli, rather than actual changes in sleep architecture, as other research suggests. Finally, research has found lower nighttime melatonin levels may contribute to poor sleep quality in those with the condition.
Beyond the time you spend in bed, digestion can mess with your sleep in other ways.
Zeitgebers (German for time-givers) are external cues that time your circadian rhythms to the outside world. Light is the most powerful one, but meals and exercise are also zeitgebers, so they can change the timing of your circadian rhythms.
If you eat a meal very late in the day or at night, you can not only throw your circadian rhythms out of whack, causing digestive issues, you can push back your sleep-wake cycle.
We’ve covered more about sleeping after eating here.
As well as sleeping on the right side (which ironically may be the left), there are other things you can do (both in and out of bed) to help digestion.
Use RISE to find out your individual sleep need and aim to meet this number each night. To help you fall and stay asleep each night, focus on your sleep hygiene.
Sleep hygiene is the name for the set of daily behaviors you can do to help you get enough sleep each night.
Here’s what to do:
If you can’t meet your sleep need at night — either due to digestive issues or something else — try taking naps during the day to keep your sleep debt low. Check RISE for the best time to nap to avoid messing up your nighttime sleep.
RISE can tell you when to do 20+ sleep hygiene habits each day at the right time for your circadian rhythm.
RISE users on iOS 1.202 and above can click here to set up their 20+ in-app habit notifications.
This key sleep hygiene habit deserves its own mention. While it’s not always possible, aim to be done with your final large meal of the day at least two to three hours before bed.
In those two to three hours, avoid laying down while watching TV or reading, as this can slow your digestion. Sit up instead. And when choosing your meals — especially if they are close to bedtime — avoid caffeine, alcohol, and sugary and spicy foods, which can disrupt your sleep and trigger digestive issues.
If you find yourself hungry at bedtime and hunger pangs are keeping you up, reach for a small snack, rather than a large meal. Try an apple, peanut butter, greek yogurt, or cottage cheese.
If this regularly happens, take a look at your diet and make sure you’re eating large enough meals throughout the day and eating a balanced diet of fruits, veggies, and complex carbs.
We’ve covered more on what time you should stop eating before bed here.
RISE can remind you when to finish up dinner each day.
RISE users on iOS 1.202 and above can click here to set up their avoid late meals reminder.
Keep your gut — and everything else — working as it should by staying in sync with your circadian rhythms.
Here’s how you can do that:
Your circadian rhythm weakens with age, so it’s even more important to keep meal and sleep times in sync as we get older.
Check RISE to see a prediction of your circadian rhythm each day and the timings of your Melatonin window.
RISE users on iOS 1.202 and above can click here to set up a reminder to check their Melatonin Window.
Time-restricted eating means you eat all of your meals for the day within a certain time frame.
While more studies need to be done to find the ideal window, a 2019 paper on the topic states eating within a 12-hour or smaller window can support good health. That would mean eating breakfast at 8 a.m., for example, and being done with dinner by 8 p.m. This would be ideal if you then went to bed at 10 p.m. at the earliest to give your body time to digest.
Intermittent fasting is often more restrictive, but it doesn’t have a set definition. It often involves eating within a smaller time window and sometimes also restricting your calories. This may be within a 12-hour window, but it’s often 10, eight, or even less.
Research from 2021 suggests intermittent fasting can help:
Beyond sleep and meal times, here’s what you can do during the day to improve your digestion:
To learn more, we’ve covered what helps with digestion here.
Although there’s some evidence that sleeping on your left is better for digestion, there’s not enough research to say for sure. We say, for optimum digestive health, you should focus on getting enough sleep (in any position), eating your final meal of the day two to three hours before bedtime, and staying in circadian alignment.
To help, the RISE app can remind you when to have your last meal of the day. It can also predict your circadian rhythm, so you can easily sync up your sleep and meals to it, and keep track of your sleep debt, so you can make sure you’re getting enough sleep in general.
By focusing on better sleep, you’ll have a knock-on effect with better digestion and better next-day energy levels, mood, and overall health.
Lack of sleep can cause poor digestion, including upper abdominal pain, nausea, reflux, diarrhea, and constipation. Not getting enough sleep has also been linked to gastrointestinal diseases like irritable bowel syndrome (IBS) and gastroesophageal reflux disease (GERD).
Lack of sleep can cause poor digestion, including upper abdominal pain and discomfort. Not getting enough sleep can also cause nausea, reflux, diarrhea, constipation, and gastrointestinal diseases like irritable bowel syndrome (IBS) and gastroesophageal reflux disease (GERD).
You digest food faster awake as many parts of your digestive system slow down during sleep. Things can also slow down when you lay down as gravity won’t be helping food move through your intestines as it does when you sit or stand up.
To improve digestion while sleeping, try lying on your left side. Gravity will help food move through your intestines. Laying on your right side, back, or stomach can increase your odds of reflux. Getting enough sleep and sleeping at the right times for your body clock will also help improve digestion.
Sleeping on your left can help digestion as gravity will help food move through your intestines. Laying on your right side, back, or stomach can increase your odds of reflux. Getting enough sleep and sleeping and eating at the right times for your body clock will also help improve digestion.
If digestion wakes you up at night, try eating your final meal two to three hours before going to bed. During this time, make sure you’re sitting or standing up to aid digestion. Getting enough sleep overall and eating and sleeping at the right times for your body clock will also reduce digestive issues that could wake you up in the night.
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