Night lights vs. pitch black: How your sleep environment affects health and longevity

He wrote in the caption, “Those sleeping in completely dark rooms have 30% lower risk of premature death, as compared to those who sleep with lights on (even if the room is dimly lit).”

Three secrets for longer and healthier life
1. Sleep in pitch darkness.
Those sleeping in completely dark room have 30% lower risk of premature death, as compared to those who sleep with lights on (even if the room is dimly lit),
2. Maintain a regular sleep schedule.
Try to go… pic.twitter.com/59sbjpV7jf

— Dr Sudhir Kumar MD DM (@hyderabaddoctor) September 27, 2024

So what exactly happens to the body when you sleep in total darkness, and how does this compare to sleeping with a night light? 

Dr Kadam Nagpal, senior consultant neurologist at Salubritus Medcentre, tells indianexpress.com, “Circadian rhythm is a 24-hour biological clock that usually coordinates the time of sleep.” He explains that light plays a crucial role in regulating this internal clock. “Whenever light enters the eye, there are special cells in the retina where the inputs are being generated and carried out to the brain, and it is being interpreted as information about the time of the day.”

How does sleeping in complete darkness affect the body’s natural circadian rhythm compared to sleeping with a night light?

The impact of light exposure on our sleep patterns is significant. Dr Nagpal reveals, “When a person is being exposed to natural light, a person’s circadian rhythm becomes synchronised with sunset and sunrise.” This natural synchronisation can be disrupted by artificial light sources.

He continues, “Whenever poorly timed artificial light exposure, such as light from a device or light from a mobile phone, is given to a person or a patient, especially at night, it can affect the sleep and wake cycle of the person and can thereby affect the circadian rhythm or the biological clock.”

Impact of exposure to light during sleep on hormone production, overall health and longevity

Light exposure significantly affects the production of melatonin, a crucial hormone for sleep regulation. Dr Nagpal explains, “Melatonin is a hormone or a neurotransmitter that is naturally made by the body, and its production is closely tied to light and response to darkness.”

He adds, “Exposure to lights slows the production of melatonin, and especially in the evening or at night as the sun sets, it brings about an increase in melatonin level, which further facilitates sleep.” This highlights the importance of controlling light exposure for optimal sleep quality.

What steps can individuals who are used to sleeping with a night light or dim lighting take to transition to sleeping in complete darkness?

Transitioning to sleeping in complete darkness can be beneficial, but it requires careful consideration. Dr Nagpal advises, “It is best to sleep whenever there is pitch darkness as pitch darkness reduces potential distractions and disruptions around us and sleep disruptions.”

He emphasises the importance of sleep hygiene: “For adequate nighttime sleep, we often encourage our patients to have adequate sleep hygiene. Sleep hygiene means the person should not consume tea or coffee before sleep, that the person should be in a very peaceful environment, that there shouldn’t be any kind of loud music, and that the nearby vicinity should be absolutely pitch dark.”

Dr Nagpal suggests practical steps for those looking to improve their sleep environment. “Even if there is some sunlight peeping in, there are blackout curtains that can be used. Also, reduce the technology in the bedroom, especially the screens’ glow light coming from the TVs or other gadgets, which might just disrupt the circadian timing and the melatonin production, thereby resulting in decreased sleep.”

Sleep hygiene is basically that the person should not have to consume tea or coffee before sleep, the person should be in a very peaceful environment, there shouldn’t be any kind of loud music, and the nearby vicinity should be absolutely pitch dark. (Source: Freepik)

Validity of the claim that sleeping in entirely dark rooms has 30% lower risk of premature death

While Dr Nagpal doesn’t directly address this specific claim, he does highlight potential health risks associated with sleeping with lights on. He states, “There are researches which often determine and depict that if the person is not sleeping in a pitch dark environment, it might result in eye strain, and there are studies that patients who sleep with the light or the TV on are susceptible to weight gain and increased cardiovascular risk, and even cancer risk is also seen to be increased in such patients.”

Dr Nagpal concludes by stressing the importance of a dark sleep environment for overall health and well-being. By following these guidelines and creating an optimal sleep environment, individuals can potentially improve their sleep quality and, by extension, their overall health.

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.