Sleep is not just a period of rest; it is an active process of restoration during which the body repairs tissues, hormones rebalance, the immune system strengthens itself, and the brain clears toxins and consolidates memory. 

Sleep is deeply intertwined with the body’s circadian rhythm, an inbuilt 24-hour biological clock that aligns human biology with the cycle of day and night. This internal clock coordinates a wide range of physiological processes including the sleep-wake cycle, hunger, body temperature, metabolism, immune function, as well as the body’s ability to perceive pain sensation. It is, therefore, important to understand that it is not just the quantity of sleep that matters but also the quality and timing that play a crucial role in overall health.  

Sleep in India  

Surveys reveal that nearly 59% of Indians get less than six hours of uninterrupted sleep daily, making the country one of the world’s most sleep deprived nations. In an age of changing lifestyle and a society where long working hours, shift employment, excessive blue light exposure and loud festive noises are increasingly common, we are witnessing a silent epidemic of sleep deprivation.  

Most of us are in a state of chronic sleep debt that exacerbates chronic pain including back pain, headaches, joint issues or post injury soreness. Poor sleep and its role in reducing pain tolerance have implications for workplace productivity, road safety, as well as mental and physical health care.   

Sleepless nights, painful days  

Our goal as healthcare professionals, as described by Edward Livingston Trudeau, the American physician, is “To cure sometimes, to relieve often, and to comfort always”.  

Sleep and pain have an intimate, yet complicated relationship. They influence each other in a bidirectional spiral. Chronic pain leads to fragmented and light sleep with frequent awakenings contributing to poor quality, non-refreshing sleep. And lack of sleep results in more pain the next day.  

Recent studies suggest that the effect of sleep on pain may be even stronger than the effect of pain on sleep. Improper or insufficient sleep disrupts the natural pain-relief mechanisms and reduces the body’s ability to tolerate pain, by lowering the pain threshold and increasing the sensitivity to pain (hyperalgesia). Researchers have found that lack of sleep causes low levels of a neurotransmitter called N-arachidonoyl dopamine (NADA) within an area of the brain called the thalamic reticular nucleus, resulting in hyperalgesia. Sleep deprivation is a stressor by itself, activating inflammation and altering brain function to amplify pain perception, thereby creating a vicious cycle where pain prevents sleep, which in turn causes more pain. Interestingly, it has been shown that even one night of sleep deprivation could significantly intensify discomfort levels.  

Effects of improper sleep 

• Reduces pain modulation - the body’s natural pain inhibitory system is blunted.
• Pain feels more intense due to the overactivity of the sensory cortex in the brain.     
• Sleep  disturbance causes a disconnect of areas of the brain (prefrontal cortex and amygdala) which impairs emotional regulation and makes pain feel more overwhelming or intolerable.  
• Lack of sleep triggers release of stress hormones, which increases irritability and impacts the mental ability to cope with physical discomfort.  
• Insufficient sleep inhibits the body’s ability to produce endorphins, the hormones responsible for reducing pain.
• Sleep is essential for tissue repair and sleep loss delays healing and therefore causes longer-lasting pain.
• Poor sleep increases inflammation and leads to long standing (chronic) low -grade inflammation that intensifies existing pain. 

Breaking the pain-sleep cycle  

Aching, sharp, shooting, piercing, dull and annoying are some of the many terms used by people to describe their pain. For some, there are ‘good’ days and ‘bad’ days; others describe their lives as ‘learning to live with pain’. Sleep is often a neglected and under-used tool when it comes to managing pain.  

For those in pain, prioritising sleep is as crucial as pain medication. Give sleep the attention it deserves, as improving sleep often reduces pain severity-sometimes more effectively than pain medication alone. Studies suggest that sleep-deprived individuals may have reduced effectiveness of pain medications requiring higher doses to achieve the same level of relief.  

Chronic pain syndromes including arthritis, headaches, neck pain, low back pain, diabetic neuropathy, fibromyalgia, myofascial pain syndromes, Complex Regional Pain Syndrome (CRPS) and cancer-associated pain are, therefore, best treated with a multidisciplinary approach including a focused evaluation and management of sleep.  

What you can do  

Good sleep habits start in the morning, so make sure you get enough sunlight exposure, regular exercise, follow a healthy diet, and have meals on time.  

Avoid stimulants such as excessive screen time, caffeine, or alcohol too close to bedtime. Maintain a strict bedtime routine, unwind before bedtime, avoid bringing life’s daily hassles into the bedroom and ensure a calm and cool sleeping atmosphere. Yoga, including meditation and breathing exercises, can help cope with both pain and sleep. Cognitive Behavioural Therapy for Insomnia (CBT-I) and medications, if required, must be used under supervision and followed up by a sleep medicine specialist.   

In conclusion, sleep acts as a frontline analgesic that is cheap and free of side effects in patients with chronic pain syndromes. For many, pillows over pain-relieving pills may be the smarter option to deal with mild discomfort. It is important to remember that rest is a prerequisite for resilience, health, and the ability to withstand pain. A multidisciplinary approach focusing on addressing the underlying problem, sleep, and the psychological aspects of dealing with pain is essential while caring for individuals with chronic pain.  

(Dr. Nagarajan Ramakrishnan is director, Nithra Sleep & Health Care, Chennai; Dr. Jayashree Rajasekaran is a fellow-in-training (sleep medicine))

(This article was first published in The Hindu’s e-book, Pain and Relief: Demystifying the Science of Suffering)