How you sleep at night might feel like a matter of comfort, but experts say your sleeping position can significantly influence posture, spinal health, and even long-term musculoskeletal wellbeing.
Given that people spend roughly a third of their lives asleep, the way the body rests for hours each night can either support the natural curve of the spine or gradually place it under strain. Poor sleep posture has been linked to back pain, neck stiffness, and posture problems during waking hours.
'Sleep and posture are closely connected', said Lisa Artis, deputy chief executive of The Sleep Charity. 'The position we sleep in can either support the natural curves of the spine or place it under unnecessary strain for hours at a time.'
According to specialists, certain sleeping positions can help maintain proper spinal alignment, while others may contribute to discomfort and long-term joint stress.
Why Back Sleeping Is Often Considered the Best for Posture
Among the most widely recommended positions for spinal health is sleeping on your back, also known as the supine position.
Back sleeping allows the head, neck, and spine to rest in a neutral position, helping maintain the spine's natural curve while distributing body weight more evenly across the mattress. Health experts say this alignment can reduce pressure on joints and muscles during the night.
The National Institute of Neurological Disorders and Stroke notes that maintaining neutral spinal alignment during rest can help minimise strain on the musculoskeletal system and reduce the risk of pain over time.
Support from the mattress and pillow is also important. A mattress that is too soft or too firm can disrupt spinal alignment, while an incorrectly sized pillow may tilt the neck out of position.
Some sleep specialists recommend placing a small pillow under the knees while lying on the back. This slight elevation helps preserve the natural curve of the lower spine and can reduce pressure on the lumbar region.
However, back sleeping is not ideal for everyone. Experts warn that it may worsen snoring or obstructive sleep apnoea in certain individuals.
The American Sleep Apnea Association explains that lying flat can allow the tongue and soft tissues at the back of the throat to collapse slightly into the airway, potentially causing breathing interruptions during sleep.
Even within this position, certain variations can create problems. Raising both arms above the head — sometimes referred to as the 'starfish' position — may place strain on the shoulders and compress nerves.
Side Sleeping: A Popular and Often Healthy Alternative
Side sleeping is another widely recommended position, particularly for people who experience breathing problems or digestive issues.
Sleeping on the side can help keep the spine relatively straight while improving airflow during sleep. According to the Cleveland Clinic, side sleeping may also help reduce acid reflux symptoms by preventing stomach acid from traveling back into the oesophagus.
Many medical experts specifically recommend sleeping on the left side for those experiencing digestive issues. Research suggests that the anatomical position of the stomach allows gravity to assist food in moving through the digestive system more efficiently.
Side sleeping is also commonly advised during pregnancy. The American Pregnancy Association recommends lying on the left side because it can improve circulation and increase blood flow to the placenta. However, the position is not without potential drawbacks. Some people experience shoulder pressure or neck discomfort if the mattress or pillow does not provide adequate support.
To improve alignment, sleep specialists often suggest placing a pillow between the knees. This prevents the upper leg from rotating forward and pulling the hips and spine out of alignment during the night.
The Foetal Position: Comfortable but Not Always Ideal
One of the most common sleeping styles is the foetal position—lying on the side with the knees drawn towards the chest and the body curled forward.
While this posture can feel comfortable and may help some individuals with lower back pain or herniated discs, experts warn that excessive curling can round the upper back and place strain on the spine.
Maintaining a looser version of the position, with the spine relatively straight rather than tightly curled, may help reduce pressure on the back and allow for deeper breathing.
Why Experts Warn Against Sleeping on Your Front
Sleeping on the stomach — also known as the prone position — is widely considered the least supportive sleeping posture for spinal health.
Although it may feel comfortable for some people, experts say the position can disrupt the natural alignment of the spine and place strain on both the neck and lower back.
Because breathing requires turning the head to one side, the neck remains twisted for long periods during the night. Over time, this can contribute to stiffness, headaches, and neck pain.
The National Sleep Foundation notes that stomach sleeping can flatten the natural curve of the spine and force the torso to sink unevenly into the mattress, creating additional strain on the lower back.
For this reason, many sleep specialists advise people who regularly sleep on their stomach to gradually transition towards side or back sleeping where possible.
How to Train Yourself to Sleep in a Better Position
Changing long-established sleeping habits can take time, but experts say gradual adjustments can help the body adapt.
Supportive pillows can be used strategically to maintain better alignment during sleep. For instance, placing a pillow behind the back may discourage rolling onto the stomach, while a pillow between the knees can help stabilise the hips when sleeping on the side.
Consistency is also important. Sleep specialists say it can take several weeks for the body to adapt to a new sleeping posture.
How Sleep Posture Can Affect Certain Health Conditions
Sleeping position may also influence several common health conditions.
People with acid reflux are often advised to sleep on their left side, as this position can reduce symptoms by limiting the upward movement of stomach acid.
Meanwhile, individuals with obstructive sleep apnoea may benefit from avoiding the supine position, since lying flat can worsen airway obstruction.
For those with lower-back pain, experts sometimes recommend placing a pillow beneath the knees when sleeping on the back or between the knees when lying on the side. These adjustments can help relieve pressure on the spine.
What Different Health Experts Say About Sleep Posture
Advice about sleep posture can vary slightly between medical disciplines.
Sleep medicine specialists often prioritise breathing and airway health, which is why side sleeping is frequently recommended for people with snoring or sleep apnoea.
Orthopaedic specialists, by contrast, tend to emphasise spinal alignment and joint pressure, which explains why back sleeping is often highlighted as a supportive option.
Physiotherapists frequently focus on practical adjustments, such as pillow placement or mattress support, to help maintain proper body alignment regardless of sleep position.
How Sleep Advice Has Evolved Over Time
Recommendations around sleeping posture have also evolved as sleep science has developed.
Earlier sleep research focused largely on comfort and mattress quality, but modern studies increasingly examine the relationship between sleep posture, spinal alignment, and chronic pain.
Organisations such as the National Sleep Foundation now emphasise maintaining a neutral spine and reducing pressure on joints as key elements of healthy sleep posture.
Do Sleeping Positions Vary Around the World?
Sleep habits can also differ across cultures and environments.
Research into sleep behaviour suggests that factors such as mattress firmness, bedding traditions, and room temperature may influence how people position themselves during sleep.
While side sleeping remains the most common position in many Western countries, studies suggest preferences can vary internationally depending on lifestyle and sleeping surfaces.
Small Changes Can Make a Big Difference
Ultimately, experts say the best sleeping position is one that maintains a neutral spine, distributes body weight evenly, and minimises pressure on joints.
Because sleep occupies such a large portion of daily life, even small adjustments in posture — such as improving pillow support or changing sleep position — can have long-term benefits for comfort, mobility, and overall spinal health.
