The chronic pain associated with arthritis is well known to negatively impact sleep. However, recent research has implied that a lack of sleep and insomnia can themselves can adversely affect arthritis symptoms.
What is arthritis?
Arthritis is an inflammatory condition of the joints and surrounding tissues. It causes pain and generally decreases the quality of life. There are over 100 different forms of arthritis; the most common types are osteoarthritis, rheumatoid arthritis, and psoriatic arthritis.
Osteoarthritis involves the breakdown of the cartilage inside of a joint, impacting the movement of the affected joint and making them painful. This can lead to severe pain as the cartilage may breakdown so much that the bones of the joint begin to rub together. The pain experienced will vary depending on the state of the cartilage.
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Rheumatoid arthritis is a result of immune responses mainly affecting the synovium of the joints. The inflammation caused by this leads to further permanent damage to the joint. Psoriatic arthritis is an autoimmune inflammatory type of arthritis where an immune response causes damage to the joints and surrounding tissue, e.g. tendons, ligaments, and skin.
The impact of lack of sleep
Lack of sleep can carry significant negative consequences for an individual. Insomnia, a condition characterized by difficulty with sleeping, affects approximately 6% to 20% of the population. Insomnia can present as trouble falling asleep or trouble to stay asleep for a desired amount of time. Subsequent symptoms of insomnia include low energy, irritability, and sleepiness during the day.
Insomnia can be categorized into two groups – primary and secondary insomnia – based on the causes. Secondary insomnia arises as to the symptom of a patient’s pre-existing condition.
Conditions such as depression, anxiety, post-traumatic stress disorder, Alzheimer's disease, Parkinson's disease, chronic pain disorders, respiratory conditions, gastrointestinal disorders, and strokes can all lead to insomnia.
Various medications can also contribute to the development of secondary insomnia. Certain asthma, allergy, and cold medicines are well-known causes of secondary insomnia; therefore, the impact to a patient’s sleep should be considered when prescribing these specific medications.
Primary insomnia has distinct mechanisms that lead to its development and is not the symptom of a different condition. Unfortunately, these mechanisms are not well understood, and researchers aim to discover any risk factors associated with primary insomnia.
The current treatments for insomnia involve pharmacological intervention as well as behavioral treatments. Unfortunately, these treatment options have limitations. Prescription medicines for insomnia allow patients to fall asleep more quickly. However, many of these medications have rare side effects such as sleep walking, which can be dangerous depending on a person’s sleep environment.
Cognitive behavioral therapy is a behavioral type of treatment for insomnia. This involves various relaxation techniques that can help to reduce anxiety, control breathing, and control moods which can promote better sleep. A major component of treating insomnia is the use of sleep hygiene strategies.
Sleep hygiene practices aim to nurture healthful habits that reduce the likelihood of insomnia. These life-style changes that can be adopted to aid with insomnia include reducing substances that worsen insomnia (e.g., coffee and tobacco), reducing time in bed while awake, abstaining from heavy meals and drinking before bed, and reducing distractions before bed time (e.g., avoiding electronic screen use in the hours before bedtime).
The effect that lack of sleep can have on arthritis
Arthritis can lead to poor sleep and insomnia due to the chronic joint pain that many patients suffer from. This impacts the patient's quality of life. Rheumatoid arthritis leads to fragmented sleep, frequent awakenings during the night, and overall poor quality of sleep
Lack of sleep can worsen the symptoms of arthritis. This can lead to a positive feedback loop in which the diminished sleep of a patient worsens arthritis-related pain, which in turn leads to even worse sleep. Research has shown that lack of sleep reduces the pain threshold and pain tolerance of an individual.
The central nervous system (CNS) has a mechanism for controlling pain perception referred to as “diminished conditioned pain modulation (CPM)”; also known as loss of diffuse noxious inhibitory controls.
The CPM involves analgesic pathways that extend from certain regions of the brain – the cerebral cortex, hypothalamus, and brainstem – to regulate the sensory input in the spinal cord. Painful stimuli cause inhibition of pain pathways which leads to a perceived reduction in pain.
Research has shown that the CPM is much lower for persons with arthritis than persons without arthritis. Additionally, a lower CPM has also been shown to negatively impact other conditions including depression and anxiety. There is also evidence that decreased CPM is associated with sleep disruptions.
This study provided insight into the direct impact that insomnia can have on arthritis and other chronic pain disorders.