Rotator cuff injuries can be debilitating, causing significant pain and functional limitations for individuals. While these injuries can cause discomfort throughout the day, many patients report experiencing intensified pain during the night. This phenomenon has puzzled both patients and healthcare professionals alike. Below we will delve into the underlying mechanisms and explore the evidence-based reasons why rotator cuff injuries tend to cause pain at night.
The Rotator Cuff: The rotator cuff is a group of four muscles and their tendons that surround the shoulder joint. These muscles play a crucial role in stabilising the shoulder and facilitating its movement. Rotator cuff injuries commonly include tears, tendinitis, or impingement of the tendons. These injuries can occur due to acute trauma, repetitive overhead activities, or the natural aging process.
The Role of Inflammation: Inflammation is a fundamental response of the body to injury. When the rotator cuff is damaged, inflammatory mediators are released, leading to increased blood flow, swelling, and localised pain. Research suggests that inflammation may be more prominent at night due to the circadian rhythm of certain immune cells, which exhibit heightened activity during the night hours. This increased inflammatory response can contribute to the heightened pain experienced by individuals with rotator cuff injuries during sleep.
Mechanical Changes: During the night, changes in body position can influence the pain experienced by individuals with rotator cuff injuries. Lying on the affected shoulder can exert pressure on the injured tissues, leading to pain and discomfort. Additionally, while sleeping, movements may be more restricted, causing the shoulder joint to remain in a static position for an extended period. This lack of movement can result in stiffness and increased pain upon awakening.
Sleeping Posture: The choice of sleeping posture can significantly impact the severity of night time pain for individuals with rotator cuff injuries. Lying on the affected shoulder can exacerbate symptoms due to increased compression and impingement of the injured tendons. Alternatively, sleeping on the opposite side or using a specialised pillow to support the injured shoulder can help alleviate pain and discomfort during the night.
Neurological Factors: Pain perception is influenced by various neurological factors. It is well-documented that pain sensitivity can be altered during sleep. Studies have shown that pain thresholds may decrease during the night, leading to a heightened perception of pain. This phenomenon can explain why individuals with rotator cuff injuries may experience more intense pain at night compared to daytime.
Psychological Factors: Psychological factors, such as anxiety, depression, and stress, can influence the perception of pain. Sleep disturbances, which are commonly associated with rotator cuff injuries, can contribute to psychological distress. Research suggests that individuals with poor sleep quality and higher levels of psychological distress may experience heightened pain intensity during the night.