Does your sleeping position affect how rested you feel when you wake up?

Sleeping position has no directly measured effect on how rested you feel when you wake up. None of the available studies measure that outcome directly. The influence runs through two indirect pathways: pain and breathing problems during sleep.

Sleeping on your back considerably increases the risk of obstructive sleep apnoea. In this position the airway collapses more easily, causing your sleep to be interrupted more frequently. People with sleep apnoea therefore wake up feeling more tired. If you suspect that you or your partner has apnoea, that is something to discuss with your doctor.

Sleeping on your stomach is associated with more lower back pain, because the lumbar spine is placed under extra strain. Pain disrupts your sleep, even if that is not measured directly. Sleeping on your back, by contrast, provides the best spinal support and is associated with fewer back complaints. All of this comes from a single systematic review of six observational studies, so the evidence is still limited.

Sleeping on your side is the most commonly used position, and here too the outcome depends on support. With a good pillow and mattress that keeps the spine straight, pain decreases. Without that support, pain can actually increase. As for pillows: better pillows (rubber or feather) do reduce neck pain and morning stiffness, but do not significantly improve measured sleep quality itself. The height and shape of the pillow appear to matter more than the material.

The honest picture: for most people without back pain or sleep apnoea, there is too little evidence to say that one position demonstrably makes you feel more rested than another. If you suffer from back pain, sleeping on your back or side (with good support) offers the best outlook. If you snore or frequently wake up tired, sleeping on your back is the least favourable choice.