As an orthopedic surgeon I see lots of people with shoulder complaints. The most common problem in the shoulder is rotator cuff tendinopathy (RCT). This is often caused by the impingement of the rotator cuff against overhead structures such as the acromion, acromioclavicular ligament and the clavicle.
Many of my patients ask whether it matters how they sleep. There’s no doubt that sleeping on the painful shoulder increases pain. You don’t need your doctor to tell you to avoid that. But does the way you sleep cause rotator cuff problems?
For the first time I’ve found a study that attempts to answer that question. The study was conducted at the University of Utah and consisted of 761 workers who were evaluated by questionnaire using a body diagram to determine the presence of shoulder pain within 30 days of enrollment. The questionnaire also assessed primary and secondary preferences for sleep positions using 6 labeled diagrams. All workers underwent a physical examination to determine if RCT was present.
The researchers made some pre-study assumptions. Overhead arm positions (Freefaller and Starfish) were assumed to cause the most likely impingement symptoms. Lateral sleep positions (Fetus) were also expected to cause problems. These were compared with the supine position (Soldier), which was assumed to cause the least impingement.
Statistical analyses for this report were:
- Prevalence of shoulder pain and RCT
- Prevalence of shoulder pain and RCT according to the sleep positions
- Odds ratio for associations between sleep position and RCT and shoulder pain
The average age was 41.8 years. Nearly 70% were female. About 36% reported shoulder pain in the 30 days prior to examination. Only 18% were actually found to have evidence of RCT on examination. Those with RCT were significantly older (45 years) than those without (41 years). These were found to have higher BMI (Body Mass Index) but there was no association with smoking or occupational exposure.
How did sleep position affect the results?
There was an association found between the Freefaller and Starfish positions and shoulder pain – but not with RCT. There was no association found between any sleep position and RCT. This was regardless of primary or secondary sleep positions. In evaluating lateral sleep position, there was a 2.06 times more likelihood that those with left shoulder pain would sleep on their right side and vice versa.
No one is going to sleep in a position that aggravates an existing problem. If you’ve got shoulder pain you’ll probably find that Freefaller, Starfish, and Fetus (on the same side) aggravates your pain. But there should be some reassurance that no matter how you like to sleep you probably aren’t going to cause rotator cuff problems.