03-06-2025
This one change in your night routine could dramatically lower your cancer risk
Cancer specialists are increasingly recognising that modern lifestyle habits — especially those affecting sleep — can influence long-term cancer risk. One of the most overlooked threats is the disruption of our body's internal clock due to artificial light, particularly the blue light emitted from digital screens.
In an interview with HT Lifestyle, Dr Kiran Kamalasanan, consultant, surgical oncology at Apollo Cancer Centre in Guwahati, explained, 'Exposure to blue light late in the evening tricks the brain into thinking it's still daytime. This delays the release of melatonin — a hormone crucial not just for sleep quality but also for regulating cellular health and immune defense.'
Studies suggest that melatonin helps suppress tumour growth and when its levels are reduced consistently, it may create a biological environment where cancer is more likely to develop. Epidemiological evidence links chronic circadian disruption, such as in night shift workers, with higher rates of breast, prostate and colorectal cancers. In fact, The International Agency for Research on Cancer (IARC) has identified night shift work involving circadian rhythm disruption as probably carcinogenic to humans.
Dr Kamalasanan revealed, 'Our circadian rhythm is a master regulator—coordinating DNA repair, hormone release, and cell division. Disturbing this rhythm can trigger inflammation, reduce the effectiveness of cellular repair mechanisms and impair the body's ability to detect and eliminate abnormal cells.'
Bringing her expertise to the same, Dr Ritika Hinduja, consultant, radiation oncology at PD Hinduja Hospital and Medical Research Centre in Mumbai's Mahim, shared, 'Poor sleep quality is a concerning public health issue. Circadian rhythm or the biological clock is the 24-hour internal clock in our brain that regulates cycles of alertness and sleepiness by responding to light changes in our environment. This is controlled by the hormone melatonin, produced by pineal gland in the brain.'
Dr Ritika Hinduja pointed out, 'Disruptions in the body's 'biological clock', which controls sleep and thousands of other functions, may raise the odds of cancers of the breast, colon, ovaries and prostate. Exposure to light while working overnight shifts for several years may reduce levels of melatonin, encouraging cancer to grow.'
Sleep deprivation also affects our immune system indicative of body being in inflammation. Dr Hinduja highlighted, 'Although vital for normal health, several decades of research have firmly implicated inflammation in the development and progression of cancer.'
The English longitudinal study of ageing has assessed the relation between sleep quality and risk of cancer. Having studied over 10000 individuals, they concluded that poor sleep quality is positively associated with the long-term risk of developing cancer in an elderly cohort.
Dr Hinduja concluded, 'Both medical staff and the general public should pay more attention to improving sleep hygiene. Cancer and sleep are intertwined in more than a single way. They emulate a chicken and egg phenomenon. Often, cancer survivors suffer from sleep problems, caused by psychological stress and recently proven, owing to the cancer and its treatment too.'
Dr Kamalasanan suggested, 'Promoting healthy sleep habits — like reducing screen exposure at night, dimming lights after sunset, and following a regular sleep schedule — is not just good for mental clarity or energy; it may be a critical component in lowering cancer risk. Good sleep is not optional. It's one of the body's strongest and most natural, lines of defense.'
Note to readers: This article is for informational purposes only and not a substitute for professional medical advice. Always seek the advice of your doctor with any questions about a medical condition.
