Is lying on your left side better for you than the right?

Why sleeping on your side is better for brain health, digestion and energy, according to scientists

Posted by for Wellbeing

Sleeping should be simple, but it turns out that there’s a science to sleeping for better brain and gut health. We ask the experts to explain.

We all want to know how to sleep better. Even if you don’t suffer from insomnia or night terrors, the chances are that you’re as obsessed with maximising your sleeping efficiency as the rest of us. Once you’ve hung the blackout blinds, banned screens from the bedroom and sworn off late-night meals, what else can you do to ensure that you’re reaping all the benefits that come from eight hours’ kip?

Ages ago, someone told me that the side you sleep on matters. Lying on one side, they claimed, was better for overall health and wellbeing while sleeping on the other side jangled your insides. It sounded (to me, at least) like rot. But could there actually be something in it? 

According to sleep therapist Dr Katharina Lederle, founder of Somnia, there is evidence to suggest that sleeping on your left-hand side can have health benefits. “It’s definitely better for pregnant women: sleeping on the left side helps to improve blood flow within the mother and also between mother and the foetus in the womb,” she explains. But it might also be beneficial for the rest of us: “[Lying on your left side] seems to reduce pressure on internal organs and supports better blood flow,” she says.

Research has found that lying on your left can also help to reduce acid reflux symptoms, with a study by the National Center for Biotechnology Information finding a positive correlation between sleeping on your right side and increased incidences of gastroesophageal reflux compared to sleeping on your left side, belly or back. However, scientists have also found that for those living with heart problems, left-side sleeping can be uncomfortable and that sleeping on the right is preferable. 

What’s the ‘right’ way to sleep?

With those conflicting studies in mind, does Dr Lederle think there’s actually a ‘right’ way to sleep? “For most of us, sleeping on your front is a bad idea; you want to keep everything aligned which is why sleeping on your back on a ‘thin’ pillow is best,” she says.

Side sleeping seems to offer some benefits, she explains, especially if you’ve got sleep apnea or heartburn, because lying on the left can improve digestion. “Side sleep also helps the removal of brain waste products which have naturally accumulated during the day. However, we do turn or move during our sleep and that is needed to prevent pressure points from building or blood flow being suppressed (which can happen if you are constantly in one position), so don’t force yourself to sleep in a certain way.”

Sleeping on your side has been linked to better brain health

A study published in the journal Translational Neurodegeneration looked into what causes motor neuron disease. Scientists wanted to examine whether it had anything to do with the body’s glymphatic system, the process for removing waste from the brain.

They explained that when things don’t work properly, the body accumulates ‘misfolded proteins’. Using mice, they examined what happened when the glymphatic system was impaired and found that teh mice started to show classic signs of brain atrophy – suggesting that you need a functioning glymphatic clearance system to maintain brain health. And you know what they said was a key factor for keeping that system healthy? Sleeping on your side.

Yep, they suggested that sleeping on your side rather than on your back can increase the brain-clearing function of glymphatic clearance. Writng in The Conversation, the study’s author David Wright said: “The reasons for this are not yet fully understood but possibly relates to the effects of gravity, compression and stretching of tissue.”

Asian woman sleeping on her back with eye mask
Lying on your back might be comfy but it's probably not the best position if you want to promote brain health and digestion.

How to sleep better for your overall posture

The thing we really need to avoid, she says, is lying on our front. By sleeping on your stomach, you’re forced to turn your head to one side, causing a misalignment of the spine and, inevitably, that increases back pain. Saying that, Dr Lederle says she “wouldn’t go as far as saying there is ‘right’ way of sleeping, but it is important to make sure you are not in pain due to how you lie in bed”.

When you’re in bed, try to lie symmetrically, making sure that your neck, spine, hips and knees are on the same level. She recommends using pillows to assist with this. “Next, try to sleep on your side but don’t force yourself to do it, and don’t beat yourself up if you wake up on your back or front. Just try again the next night. And remember, changing sleep position while asleep is normal.”

For more sleeping tips and tricks, visit the Strong Women Training Club.

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Miranda Larbi

Miranda Larbi is the editor of Strong Women and Strong Women Training Club. A qualified personal trainer and vegan runner, she can usually be found training for the next marathon, seeking out vegan treats or cycling across London on a pond-green Tokyo bike.