How often do you toss and turn in bed? When counting sheep, just doesn’t help, is there anything else that can be done? The solution may be as simple as ensuring that your bedroom is pitch black. The Internet of things for Sleep monitoring, 2021, a study in IEEE journal found that the environment is critical for proper sleep. After years-long research, studies cumulatively support that sleeping in a dark room promotes restorative sleep. Here’s how darkness improves sleep quality and benefits your health.

 

Sleeping in a dark room helps to maintain our sleep-wake cycle

We are born with an internal clock that controls our sleep-wake cycle. This internal clock is called the circadian rhythm and it works on internal and external cues. One of the main external cues to wake up is light. At the brink of dawn, our body prepares itself to wake up and function. Similarly, our body produces a signal to prepare itself to go to sleep and rest. The said signal is a serotonin derived hormone produced by our body called melatonin. The pineal gland in our body produces melatonin in response to darkness to increase sleepiness. Conversely, when our body is exposed to light, it ceases the production of melatonin and thereby disrupts the sleep cycle. Backing this data is a study by Katsuhiro Mitsui and team in Sleep Medicine, 2022, that associates light with decreased melatonin production and sleep disturbance.

 

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Sleeping in darkness promoted better fat metabolism

Sleep experts recommend that 8 hours of uninterrupted sleep is mandatory for healthy living. During sleep, our body relaxes, paving the way to fast metabolism. Faster metabolism enables the body to utilise stored energy (read: fat) more efficiently. However, even a glimpse of light slows the metabolism, thereby impacting our body’s ability to convert fat into energy. Several studies including Miller and team's paper in Obesity reviews, 2021 show that sleeping in light increases body weight by 50 per cent. Another paper by Megan E Petrov, 2021 in Pediatric Obesity, 2021 concludes that “early life sleep patterns (disturbed sleep) will result in obesity outcomes”.

 

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Exposure to light during the night increases the chances of developing breast cancer

Interruption of sleep causes a plethora of hormonal and biochemical changes in our bodies. One of the deadly outcomes of this disruption is cancer. A severe year-long follow-up study published in the International Journal of Cancer, 2017 showed a higher risk of developing breast cancer in women who slept in total darkness but were interrupted by light. Further on, case studies by Johnni Hansen and Richard Stevens show that nurses who work the night shift and sleep during the day are prone to higher risks of breast cancer, Elsevier.

 

Sleeping in the dark reduces the risk of cardiometabolic impairment

A research paper in PNAS nexus, by Ivy C Mason and team, in March 2022, associates light exposure during sleep with increased heart rate, decreased heart rate variability, and insulin resistance. Insulin resistance for prolonged period of time results in diabetes.

 

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Exposure to light during sleep is associated with depression

Light exposure during sleep is related to health complications such as depression and anxiety. A study from the American Journal of Epidemiology, 2017 shows the association between exposure to low light during sleep and depression risk in young adults.