Sleep is an inevitable process in human life. It plays a major role in repair, recover the body condition, also the
amalgamation and consolidation of memory. Humans spent one third of their lifetime in sleeping. A quality sleep can eliminate physical and mental fatigue, facilitate the energy and physical restoration, and ensure the overall well functioning of the body.1
Posture is typically defined as the bio-mechanical, spatial alignment of body parts in relation to their segments. In healthy individuals, a good night’s sleep is immensely affected by the different sleeping positions.
“The best or the ideal sleeping position is the one that decreases the stress, releases the muscles and encourage a better body balance”.2
This article focuses on the types of sleeping positions, with an emphasis on the effects of sleeping on stomach on sleep, overall health and some tips for better sleep in stomach sleepers.
Types of sleep positions
Sleep positions i.e. front, back, or side, movements of the arm, thigh, back, number of positional shifts all keep on changing throughout the sleep. Every individual has a particular sleep pattern or habitual sleep position that helps in initiating the sleep and providing a good night sleep. Some of the common sleeping positions are as follows:
Sleeping on back (supine position): In this position, the head, neck, back and spine all are in a straight line and a neutral position.1,3 It is considered as the healthiest option for sleeping but not the popular one. Sleeping in this position helps in relieving the extra pressure from the spine, and helps the patients with back issues. However, in patients with obstructive sleep apnea, it can lead to obstruction of airway by the backward movement of the tongue causing difficulty in breathing.
Sleeping on side (lateral decubitus position): In this sleeping position, lying sideways when the torso and legs are relatively in a straight line.3 This is the most commonly opted sleeping position as compared to supine and prone. It has been documented that more than 60% of the European adults adopt sleeping on side for the majority of the night sleep. Sleeping on side helps in reducing back and neck pains. It also helps in patients with acid reflux and
gastrointestinal issues.4
Sleeping on stomach (prone position): This is the sleeping position, which is opposite of the supine position. In this position, the torso and legs are in straight line while lying on stomach. The position of the head varies in left or right direction to maintain the airway and prevent any breathing difficulties. A pure prone position can be achieved by using a pillow mounted on a table with a hole in the middle part to support the head restricting the lateral rotations. These pillows are manufactured by researcher’s in variable sizes to adjust the patient’s neck, head and face. These are made up of sponge and used for the research purposes.5
Although sleeping on stomach is harmful for the neck, back and muscle pains. It increases the intraocular pressure in healthy individuals and increases the risk for glaucoma. However, sleeping in prone position helps the patients with obstructive sleep apnea and reducing the blood pressure in pregnant females with pre-eclampsic conditions.
Effects of sleeping on stomach on the different systems:
Cardiovascular: It has been postulated that the sleeping in this position can cause compression of thorax leading to significant decrease in stroke volume. The reduction in stroke volume reflects decrease in arterial filling and pulsation causing some inhibition of arterial baroreceptors. This could in turn increase the sympathetic nervous system activity, heart rate and total peripheral vascular resistance.6
Ocular: Increased intraocular pressure (IOP) has been classified as a risk factor for the increased incident and progression of open angle glaucoma (OAG). The elevation in IOP has been calculated on change of position from sitting to lying down in young or healthy individuals. Studies have demonstrated that as compared to supine or lateral positions, increase in IOP is more commonly associated with prone position or sleeping on stomach. However, studies are required to get a clear picture of IOP changes in relation to sleeping in prone position with head tilted downwards or sideways.7
Respiratory: The number and duration of respiratory problems with obstructive sleep apnea (OSA) is highly
impacted by sleeping positions and sleep stage. As discussed in several studies sleeping in lateral positions is believed to reduce the tendency for the tongue to fall backwards as compared with supine position. Bidarian-Moniri A, et al. (2015) reported that sleeping in prone position as compared to both lateral and supine positions reduce the airway collapse with improved apnea-hypoapnea index (AHI) and oxygen desaturation index (ODI).8 Afrashi A and Ucar ZZ. (2015) also studied the effects of prone positioning in mild to moderate obstructive sleep apnea syndrome patients. It was observed that sleeping in prone positioning helps in improving AHI and ODI in mild to moderate OSA.5
On infant sleep and arousal: Several studies have documented that prone sleeping position or sleeping on stomach is associated with impaired arousal from sleep in healthy infants.9 The prone positioning has been identified as a major risk factor for sudden infant death syndrome in infants ages between 1 month to 1 year. Various mechanisms such as accidental suffocation, oropharyngeal obstruction, displacement of mandible posteriorly, increased upper respiratory airway resistance, rebreathing of carbon dioxide, overheating, formation of nasal bacterial toxins, impairment of autonomic function, defective arousal response are postulated to explain the association of prone sleeping position and sudden infant distress syndrome (SIDS).10
In pregnancy: In healthy pregnancy and pregnant females with hypertension sleeping in prone position with proper pillow support for short period of time helps in reducing the blood pressure with obvious adverse effects.11
Nervous system disorders:People with epilepsy, who sleep in prone position or sleep on stomach have higher risk for sudden unexpected death syndrome when compared with other positions. Liebenthal JA, et al. (2015) reviewed the association between prone position and sudden unexpected death in epilepsy (SUDEP) and observed the risk of SUDEP increases significantly in patients aged over 40 years or younger.12
On spine and muscles:Sleeping in prone position is commonly associated with muscle soreness, pain in the back, neck and joints in the morning. It is mostly due to the misalignment in the head, neck, torso and legs in order to support the side positioning of the head to maintain the patent airway for breathing.
Tips for stomach sleepers
Despite all the adverse effects of sleeping on stomach. Some people are habitual to sleep in prone position. There are some tips for the stomach sleepers:
Use a thin or no pillow or place a pillow under the pelvis. It helps in keeping the back in more neutral position, relieving the pressure off the spine.
A T-shaped pillow, enabling head and forehead support for a well aerated breathing. It can be placed on a normal mattress, hence compatible with the existing bed.13
Some simple stretching exercises in the morning can also help in relaxing the sore muscles.
Conclusion
Sleep is very importing for proper functioning of cognitive and behavioral aspects of human life. A deprived or disturbed sleep can increase the risk of several health issues. The restoration of the body functioning is immensely affected by the sleeping position. Although sleeping on stomach or in prone position is not considered a healthy option as it can lead to multiple health problems but in some specific conditions sleeping on stomach can be beneficial for the patient under a professional supervision. It is important for the habitual stomach sleepers to change the sleeping position or to use the appropriate pillow and mattress as the support system.
References
Pan H, Xu Z, Yan H, et al. Lying position classification based on ECG waveform and random forest during sleep in healthy people. Biomed Eng Online. 2018;17(1):116. doi:10.1186/s12938-018-0548-7
Desouzart G, Matos R, Melo F, Filgueiras E. Effects of sleeping position on back pain in physically active seniors: A controlled pilot study. Work. 2015;53(2):235-240. doi:10.3233/WOR-152243
Hsia CC, Liou KJ, Aung AP, Foo V, Huang W, Biswas J. Analysis and comparison of sleeping posture classification methods using pressure sensitive bed system. Conf Proc IEEE Eng Med Biol Soc. 2009; 2009:6131-6134. doi:10.1109/IEMBS.2009.5334694
Cary D, Briffa K, McKenna L. Identifying relationships between sleep posture and non-specific spinal symptoms in adults: A scoping review. BMJ Open. 2019;9(6):e027633. doi:10.1136/bmjopen-2018-027633
Afrashi A, Ucar ZZ. Effect of prone positioning in mild to moderate obstructive sleep apnea syndrome. Sleep Breath. 2015;19(3):1027-1034. doi:10.1007/s11325-014-0985-x
Pump B, Talleruphuus U, Christensen NJ, Warberg J, Norsk P. Effects of supine, prone, and lateral positions on cardiovascular and renal variables in humans. Am J Physiol Regul Integr Comp Physiol. 2002;283(1):R174-R180. doi:10.1152/ajpregu.00619.2001
Lee TE, Yoo C, Kim YY. Effects of different sleeping postures on intraocular pressure and ocular perfusion pressure in healthy young subjects. Ophthalmology. 2013;120(8):1565-1570. doi:10.1016/j.ophtha.2013.01.011
Bidarian-Moniri A, Nilsson M, Rasmusson L, Attia J, Ejnell H. The effect of the prone sleeping position on obstructive sleep apnoea. Acta Otolaryngol. 2015;135(1):79-84. doi:10.3109/00016489.2014.962183
Horne RS, Ferens D, Watts AM, et al. The prone sleeping position impairs arousability in term infants. J Pediatr. 2001;138(6):811-816. doi:10.1067/mpd.2001.114475
Horne RS, Franco P, Adamson TM, Groswasser J, Kahn A. Effects of body position on sleep and arousal characteristics in infants. Early Hum Dev. 2002;69(1-2):25-33. doi:10.1016/s0378-3782(02)00025-7
Dennis AT, Hardy L, Leeton L. The prone position in healthy pregnant women and in women with preeclampsia – a pilot study. BMC Pregnancy Childbirth. 2018;18(1):445. doi:10.1186/s12884-018-2073-x
Liebenthal JA, Wu S, Rose S, Ebersole JS, Tao JX. Association of prone position with sudden unexpected death in epilepsy. Neurology. 2015;84(7):703-709. doi:10.1212/WNL.0000000000001260
Bidarian-Moniri A, Nilsson M, Attia J, Ejnell H. Mattress and pillow for prone positioning for treatment of obstructive sleep apnoea. Acta Otolaryngol. 2015;135(3):271-276. doi:10.3109/00016489.2014.968674
Dr Harshi Dhingra is a licensed medical doctor and specialized Pathologist with research, diagnostic, clinical and teaching experience of over a decade, currently employed as faculty in a medical school with tertiary care hospital and research center. She has keen interest in medical content research writing and reviewing. She has several publications in indexed peer reviewed journals. She was awarded for best paper presentation in a state level conference. She holds medical degrees of MBBS and MD Pathology.
