A strong immune system is often associated with supplements, superfoods, or intensive wellness routines. But according to cancer surgeon Dr Tarang Krishna, many people overlook the one habit that quietly weakens their body’s natural defences every day.
In a recent Instagram post, he stressed that sleep is the true foundation of immunity, saying, “You know the key to your immune system? And that key is sleep. Poor sleep weakens your immunity. When your sleep is disturbed, your body becomes more susceptible to fatigue, diabetes, autoimmune disorders, and many other illnesses.”
He pointed out that the body already has powerful healing capabilities, but lifestyle habits often get in the way. As he explained, “Our body has the natural ability to fight diseases, but we don’t use it properly. This is because during sleep time, we are often glued to our phones. To reduce inflammation in our body, we need proper sleep.”
Dr Krishna also broke down the science behind this, emphasising the role of melatonin. He said, “When we stay awake, the hormone melatonin, which is the sleep hormone, doesn’t get a chance to work. And this is why our immune system cannot recharge. To strengthen our immunity, we need to let our system recharge, and proper sleep is essential for that.”
So what are the earliest physiological signs that lack of sleep is beginning to impair immune function?
Dr Palleti Siva Karthik Reddy, MBBS, MD, general medicine, consultant physician, tells IndianExpress.com, “Even a single night of inadequate sleep can trigger measurable changes in immune activity. One of the earliest signs is a rise in inflammatory markers such as C-reactive protein and interleukin 6, which indicates that the immune system is shifting into a stressed state. People also experience subtle symptoms like increased irritability, reduced concentration, and slower recovery from minor exertion. These behavioural changes often reflect deeper physiological shifts, including a reduction in natural killer cell activity, which is a frontline defence against viruses and abnormal cells. These alterations can begin within 24 hours of sleep disruption and become more pronounced with each consecutive night of poor sleep.”
Over time, he adds, this chronic low-grade inflammation weakens the body’s ability to respond to infections and increases vulnerability to metabolic disorders.
Practical steps to restore melatonin rhythms and strengthen immunity without relying solely on supplements
Dr Reddy notes, “People with irregular work hours, chronic stress, or insomnia can stabilise melatonin rhythms by focusing on consistent behavioural cues that support circadian alignment. Maintaining a fixed sleep and wake time, even on weekends, helps regulate the internal clock. Reducing screen exposure at least one hour before bedtime and using warm or dim lighting in the evening reduces light-driven melatonin suppression.”
Engaging in daytime exposure to natural light, Dr Reddy informs, particularly morning sunlight, strengthens the melatonin cortisol cycle and improves nighttime sleep readiness. Stress management practices such as deep breathing, progressive muscle relaxation, and short evening routines signal the body to wind down.
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“Limiting caffeine after the early afternoon and avoiding heavy meals late in the evening also supports healthier melatonin secretion. These non-pharmacological interventions can significantly improve sleep quality and immune resilience without depending primarily on supplements,” concludes the expert.
DISCLAIMER: This article is based on information from the public domain and/or the experts we spoke to. Always consult your health practitioner before starting any routine.
