Sleep Science: Can Sleeping in a Dark Room Help You Live Longer?

You must have heard that sleeping in complete darkness can improve sleep quality, leaving us feeling refreshed and energized the next day. What may surprise you is that sleeping in the dark⁠ can improve longevity too. This article explores how sleeping in total darkness can help you live longer and gives you tips on how you can create a dark room for sleeping.

Light pollution – statistics:

People were exposed to minimal light during bedtime before electric lights were invented. Now, we are surrounded by many light sources at night, from televisions and computer screens to smartphones and tablets.

Research shows that over 80% of the global population and more than 99% of individuals residing in the United States or Europe live in areas with significant light pollution.

The consequences of being exposed to light at night should not be ignored. Consistent data links long-term exposure to artificial light at night and health conditions, including heart disease, obesity, diabetes, and cancer.

Light at night disrupts the sleep-wake cycle

Light exposure before and during bedtime can disrupt the natural sleep-wake cycle, making it harder to fall asleep and stay asleep.

Our bodies produce melatonin, a hormone that helps regulate sleep. The peak in melatonin production typically occurs in the middle of the night. When you repeatedly expose yourself to electrical lighting at night, you disturb melatonin production, leading to insomnia and other sleep disorders.

Ana Luiza Agamme, PhD, specializing in sleep sciences

Melatonin has also been shown to lower blood pressure and body temperature. Therefore, chronic exposure to electrical lighting at night could affect not only sleep, but also the regulation of body temperature and blood pressure.

How sleeping in a dark room can improve longevity

Sleeping in a dark room can offer many benefits to your health, including improving longevity. Here are some ways sleeping in a dark room can contribute to a longer and healthier life.

Regulated melatonin production

Sleeping in a dark room can improve the quality of sleep by regulating the production of melatonin. This synchronizes your body's natural sleep-wake cycle, improves your overall health, and potentially prolongs your life.

“Beyond its function in the sleep-wake cycle, melatonin is a hormone with antioxidant properties,” explain Agamme. “This suggests that melatonin can protect cells from the oxidative damage associated with age-related pathologies, including cardiovascular and neurodegenerative disorders.”

Also important, melatonin has anti-inflammatory properties, making it a promising agent for preventing inflammatory disorders. Because chronic inflammation increases with aging and is involved in many age-related diseases, sleeping in a dark room to regulate melatonin production can be particularly useful for older adults.

Reduced risk of chronic diseases

As research continues to evolve, it appears that there is a link between prolonged exposure to light during nighttime hours and an increased risk of certain diseases, such as cancer and obesity.

Studies with people who work night shifts and are exposed to daylight-like conditions during their work hours primarily support this theory. This often occurs with nurses and flight attendants, for example.

A recent study even shows that exposure to a single night of room light during sleep increases measures of insulin resistance the following day.

Insulin resistance is a condition in which the body's cells do not respond properly to insulin, a hormone that helps to regulate blood sugar levels. Over time, this can lead to an increased risk of diabetes and other health problems that can affect longevity.

So, to achieve optimal health, you must aim for both enough sleep and enough darkness.

Reduced risk of depression

A study found that exposure to light at night (even at levels as low as five lux) increases the risk of older adults experiencing depression.

According to the same study, the most significant effect on mood occurred in people exposed to light around bedtime. Moreover, the longer the exposure to light at night, the greater the risk of depression.

The mechanisms behind this association are not fully understood, but previous research has suggested that exposure to light at night can disturb sleep, impair melatonin secretion, and misalign the body's circadian rhythm. These conditions are commonly associated with depression.

So, you ask, does depression shorten life expectancy?

Yes. Depression increases the risk of chronic health conditions such as heart disease, diabetes, and stroke. These conditions can lead to premature death if they are not properly managed.

Individuals with depression may also have a reduced ability to adhere to medical treatment, which can further increase the risk of chronic health conditions and suicide.

By reducing your risk of depression, you can reduce your risk of developing these adverse health outcomes and improve your longevity.

Tips for creating a dark room for sleeping:

Not sleeping in total darkness but want to try it out? Here are some tips to help you create a dark room for sleeping:

1. Use shields or directional lighting fixtures in outdoor spaces. This will direct light away from windows and help reduce light pollution.
2. Install a solid-core door. This can help block out noise and light from outside the bedroom, creating a more conducive sleep environment at night.
3. Use weather stripping or caulking to seal gaps around windows and doors. This prevents light and noise from entering the room.
4. Use blackout curtains or blinds. These can block out light from the outside and create a dark environment for sleeping.
5. Unplug electronic devices. Electronic devices such as smartphones and tablets emit blue light, which can disrupt melatonin production. Unplugging these devices at night can promote healthy sleep.
6. Avoid artificial light sources. Artificial light sources such as nightlights and alarm clocks can also disrupt melatonin production. It is essential to avoid these light sources at night.
7. Avoid being exposed to white or blue light. If you need a light for safety, amber, or red/orange light is less stimulating for the brain and less likely to suppress melatonin production.
8. Use a sleep mask. If you can't apply the above strategies, a sleep mask can help block light and promote healthy sleep.

Look at your current habits and sleep environment. Try implementing some tips above — even if only for a week. And remember, sleep is essential for overall health and well-being, so make sure to get enough sleep each night.