When people talk about being a “sound sleeper,” it often conjures the image of someone who drifts off easily and spends the night perfectly still. But in reality, sound sleepers do not remain motionless. Movement during sleep is not only normal but also a sign of healthy sleep cycles. The human body shifts positions several times throughout the night to reduce pressure on muscles and joints and to improve circulation. Even those considered deep or sound sleepers will experience tossing, turning, or subtle micro-movements.
Research shows that on average, most people change positions between 10 and 40 times per night. According to the National Sleep Foundation, these movements often go unnoticed because they occur during lighter stages of sleep. However, even during deep sleep, the body will occasionally adjust. These movements are thought to be protective, preventing bedsores, nerve compression, or poor blood flow that could result from lying too long in one position.
Sleep tracking studies using polysomnography, a clinical tool that monitors brain waves, breathing, and body movements, reveal that complete stillness is rare. A study published in Sleep Medicine Reviews found that movement varies by age, with younger adults moving more frequently and older adults sometimes showing less variability. This decline in movement with age can be linked to changes in sleep structure and health conditions that affect mobility.
Sound sleepers are often characterized not by stillness but by their ability to fall asleep quickly, stay asleep with fewer awakenings, and move naturally without fully waking. In fact, an absence of movement could sometimes be a red flag. For example, disorders such as sleep apnea or periodic limb movement disorder can alter the normal rhythm of nighttime movements. Conversely, medications or certain neurological conditions may lead to unusually rigid or limited movement during sleep.
It is also worth noting that the stages of sleep affect how much movement occurs. During REM sleep, the body experiences temporary muscle paralysis known as atonia, which prevents people from physically acting out their dreams. In contrast, non-REM sleep allows for more physical adjustments. This balance is important, as both movement and immobility play distinct roles in maintaining healthy, restorative sleep.
So, while sound sleepers may appear still compared to restless sleepers, their bodies are still actively shifting and adjusting throughout the night. Rather than focusing on staying perfectly still, the key markers of quality sleep are how refreshed you feel in the morning, how often you wake during the night, and how consistent your sleep routine is.
Disclaimer: This article is for informational purposes only and should not be taken as medical advice. If you experience abnormal sleep movements, excessive restlessness, or discomfort that disrupts your sleep, consult a healthcare professional or a sleep specialist for proper evaluation.
References:
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National Sleep Foundation. (2021). Understanding sleep cycles. Retrieved from https://www.thensf.org
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De Koninck, J., et al. (1992). Body movements in sleep: Significance and clinical relevance. Sleep Medicine Reviews, 6(3), 179–202.
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American Academy of Sleep Medicine. (2022). Normal sleep patterns and changes with age. Retrieved from https://aasm.org
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Carskadon, M. A., & Dement, W. C. (2017). Normal human sleep: An overview. Principles and Practice of Sleep Medicine.