How Sunlight Benefits Your Brain

A little daylight can help you focus, feel perkier and sleep better, research suggests

Christine Richmond

Updated May 22, 2026

A man with his eyes closed basking in the sun in a forest

Olena Ruban/Getty Images

The next time you’re hit with a post-lunch energy slump, take a brief walk outside. If that’s not an option, plop yourself next to the sunniest window you can find.

Why? Daylight is a major source of blue wavelengths of light, which research has shown can boost your alertness, concentration and even your mood. “Light is like a cup of coffee,” says Mariana G. Figueiro, director of the Light and Health Research Center at Mount Sinai.

How does daylight perk you up? It triggers your body’s circadian rhythm — the internal “clock” in your brain. In response to light, your circadian clock signals you to be more alert. Later, when the sun goes down, your circadian clock promotes sleep.

“It’s almost like a switch,” Figueiro says. Many brain chemicals are involved in this complex interplay. For example, light kicks off production of serotonin, known as a “feel-good” hormone because it contributes to positive emotions and behavior. Later, darkness cues production of melatonin, a hormone that makes us drowsy.

That dose of sunlight will make you feel more alert, and you may also have a sunnier outlook. People who got the most natural light during the day were happier and less likely to have symptoms of depression than those who got the least, according to a study of 502,000 adults between the ages of 37 and 73, published in the Journal of Affective Disorders in 2021.

Exposure to daylight may support your memory and thinking skills, too. One study, published in Scientific Reports in 2022, analyzed cognitive testing data from 1,838 adults, average age 42. The researchers also reviewed several years’ worth of solar radiation data based on participants’ zip codes and found that people living in the sunniest areas for two to five years before the cognitive tests had better scores than those who got the least daylight.

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The key times of day

Your circadian rhythm is most receptive to signals from the amount of light in your environment during the first two hours after you wake up and the two hours before bedtime, Figueiro explains.

That’s why basking in morning light soon after you get out of bed — ideally for at least an hour, but even 30 minutes will make a difference — is an especially effective way to support your sleep/wake cycle and get a good night's sleep, Figueiro says. One study of 1,762 adults 18 and older, published in BMC Public Health in 2025, found that people who got the most sunlight before 10 a.m. had better overall sleep quality.

The blue light wavelengths that LED bulbs and electronic devices emit can also fool your circadian rhythm into thinking it’s daytime, keeping you awake, which is why experts recommend you dim things down in the lead up to bedtime.

Science journalist Rowan Jacobsen experienced this firsthand. He struggled with sleep problems for years beginning in his 40s, but he discovered that “if I get enough intense light during the day, and a really dark sleeping environment, the insomnia disappears.” He researched the brain benefits of daylight while writing his 2026 book “In Defense of Sunlight” and has come to view morning light as “nonnegotiable.” Most days, he rises at dawn, has a cup of coffee, and then heads outside for a run or a swim.

“It’s incredible how different my mood is if I’m able to get the morning light in my eyes and on my skin,” he says. When that’s not possible, he sips his coffee “while staring out the window at the day breaking,” he says. “That’s not as good as being out in it, but it’s a lot better than nothing.”