Sleeping in complete darkness: How it helps prevent Cancer growth
We all know how sleep plays a crucial role in our health. While our physical bodies rest, our brain during that time, performs some key activities like waste removal, memory consolidation, cell repair, energy restoration and many more. While everyone has their own consensus on how they want to sleep, doctors believe that sleeping in pitch darkness (With a source of light close by to switch on to avoid accidents) is extremely beneficial for health. The trick to test it? If you can see your palm in the dark, your room is still too bright. This apart, the dark can positively affect your body’s natural processes, including how your cells grow and repair. However, that is not all. Do you know that sleeping in complete darkness also prevents Cancer growth? Here's how...
Why dark matters
Our bodies follow a natural 24-hour cycle called the circadian rhythm. This internal clock controls many functions, such as when we feel awake or sleepy, hormone release, and cell repair. Light is the main signal that tells our brain when it’s time to be awake or asleep.
When you sleep in a room with lights, on or even small amounts of light (even from outside), it can confuse your brain. This disrupts your circadian rhythm and affects the production of important hormones like melatonin.
The importance of Melatonin
Melatonin is often called the “sleep hormone” because it helps regulate sleep-wake cycles. It is produced by the pineal gland in the brain, mainly during the night when it is dark. Melatonin not only helps you fall asleep, but also has powerful antioxidant properties.
Antioxidants protect your cells from damage caused by harmful molecules called free radicals. Free radicals can cause mutations in your DNA, which may lead to cancer. Melatonin helps neutralize these free radicals and supports your immune system in fighting abnormal cell growth.
How the dark reduces Cancer Risk
Exposure to light during sleep lowers melatonin production. Studies have found that people who are exposed to light at night, such as shift workers or those who sleep with lights on, have lower melatonin levels. This reduction can weaken the body’s natural defense against cancer.
The International Agency for Research on Cancer (IARC) has classified shift work involving circadian disruption as a probable carcinogen. This means that disrupting your natural sleep cycle by being awake at night or sleeping with light can increase the risk of developing certain cancers, especially breast and prostate cancer.
What does science say
Several research studies support the idea that sleeping in complete darkness may help prevent cancer growth:
A 2014 study published in the journal Cancer Causes & Control showed that women who slept in rooms with light exposure had a higher risk of breast cancer compared to those who slept in complete darkness.
Research from the University of Texas found that melatonin can slow the growth of cancer cells in laboratory experiments, especially breast and colon cancer cells.
Another study in Chronobiology International found that people with lower nighttime melatonin levels were more likely to develop cancer over time.
Tips for sleeping in darkness
To improve your sleep environment and help your body produce melatonin naturally, try the following:
Use blackout curtains: These block outside street lights or sunlight from entering your room.
Remove electronic devices: Turn off or cover screens from phones, computers, and TVs, as they emit blue light that suppresses melatonin.
Use a sleep mask: If blackout curtains are not an option, a comfortable eye mask can help block light.
Avoid night lights: Even small night lights can reduce melatonin production.
Keep your bedroom dark during naps: If you nap during the day, try to rest in a dark room to maintain your circadian rhythm.
Other Benefits of Sleeping in Darkness
Besides cancer prevention, sleeping in complete darkness has many other health benefits:
Better sleep quality: Darkness helps you fall asleep faster and stay asleep longer.
Improved mood: Proper sleep reduces stress and lowers the risk of depression.
Stronger immune system: Good sleep supports your body’s ability to fight infections.
Balanced hormones: Darkness helps regulate hormones related to appetite, growth, and stress.
Sources
https://monographs.iarc.fr/wp-content/uploads/2018/06/mono98.pdf
https://pubmed.ncbi.nlm.nih.gov/24748058/
https://pubmed.ncbi.nlm.nih.gov/26972464/
https://pubmed.ncbi.nlm.nih.gov/19129209/
https://www.uth.edu/news/story.htm?id=2c8eebf4-1d1f-4a5f-9f8f-3e9d5d9d3b2a
Why dark matters
Our bodies follow a natural 24-hour cycle called the circadian rhythm. This internal clock controls many functions, such as when we feel awake or sleepy, hormone release, and cell repair. Light is the main signal that tells our brain when it’s time to be awake or asleep.
When you sleep in a room with lights, on or even small amounts of light (even from outside), it can confuse your brain. This disrupts your circadian rhythm and affects the production of important hormones like melatonin.
The importance of Melatonin
Melatonin is often called the “sleep hormone” because it helps regulate sleep-wake cycles. It is produced by the pineal gland in the brain, mainly during the night when it is dark. Melatonin not only helps you fall asleep, but also has powerful antioxidant properties.
Antioxidants protect your cells from damage caused by harmful molecules called free radicals. Free radicals can cause mutations in your DNA, which may lead to cancer. Melatonin helps neutralize these free radicals and supports your immune system in fighting abnormal cell growth.
How the dark reduces Cancer Risk
Exposure to light during sleep lowers melatonin production. Studies have found that people who are exposed to light at night, such as shift workers or those who sleep with lights on, have lower melatonin levels. This reduction can weaken the body’s natural defense against cancer.
The International Agency for Research on Cancer (IARC) has classified shift work involving circadian disruption as a probable carcinogen. This means that disrupting your natural sleep cycle by being awake at night or sleeping with light can increase the risk of developing certain cancers, especially breast and prostate cancer.
What does science say
Several research studies support the idea that sleeping in complete darkness may help prevent cancer growth:
A 2014 study published in the journal Cancer Causes & Control showed that women who slept in rooms with light exposure had a higher risk of breast cancer compared to those who slept in complete darkness.
Research from the University of Texas found that melatonin can slow the growth of cancer cells in laboratory experiments, especially breast and colon cancer cells.
Another study in Chronobiology International found that people with lower nighttime melatonin levels were more likely to develop cancer over time.
Tips for sleeping in darkness
To improve your sleep environment and help your body produce melatonin naturally, try the following:
Use blackout curtains: These block outside street lights or sunlight from entering your room.
Use a sleep mask: If blackout curtains are not an option, a comfortable eye mask can help block light.
Avoid night lights: Even small night lights can reduce melatonin production.
Keep your bedroom dark during naps: If you nap during the day, try to rest in a dark room to maintain your circadian rhythm.
Other Benefits of Sleeping in Darkness
Besides cancer prevention, sleeping in complete darkness has many other health benefits:
Better sleep quality: Darkness helps you fall asleep faster and stay asleep longer.
Improved mood: Proper sleep reduces stress and lowers the risk of depression.
Stronger immune system: Good sleep supports your body’s ability to fight infections.
Sources
https://monographs.iarc.fr/wp-content/uploads/2018/06/mono98.pdf
https://pubmed.ncbi.nlm.nih.gov/24748058/
https://pubmed.ncbi.nlm.nih.gov/26972464/
https://pubmed.ncbi.nlm.nih.gov/19129209/
https://www.uth.edu/news/story.htm?id=2c8eebf4-1d1f-4a5f-9f8f-3e9d5d9d3b2a
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