In the quest for better sleep, you can splurge on the plushest mattress and the darkest blackout curtains. But one of the most effective (and free) ways to get deeper rest, better daytime energy, and a steadier mood is simply stepping outside for morning sunlight.
Early morning exposure to sunlight is among the most underrated biohacks for better rest—no supplements, red-light therapy, or high-tech sleep trackers necessary. We spoke to experts and looked at the research to explain why this unsung hero of sleep is worth a spin.
Why your best sleep starts in the A.M.
The secret to getting good sleep truly begins as soon as you wake up. “Morning sunlight is one of the strongest signals for resetting the body’s circadian rhythm,” says Michael Howell, MD, a sleep medicine physician and chief medical officer at GEM Sleep. Early light tells your brain to stop producing melatonin (aka the sleep hormone) and triggers the production of cortisol to not only increase alertness but also support daytime energy levels, mood, and metabolic regulation.
Light exposure also has effects beyond the circadian system. “A major misconception is that light’s influence is limited solely to the canonical circadian pathway through the suprachiasmatic nucleus (SCN),” a part of the brain that functions as the body’s internal clock, says Samer Hattar, PhD, a neuroscientist and the chief of Section on Biological Roles of Light and Circadian Rhythms at National Institutes of Mental Health.
However, recent research (including Hattar’s own work) shows additional SCN-independent pathways—what he calls the tripartite model of light’s influence on light-mediated behaviour. “Light inputs, circadian signals, and the homeostatic drive for behaviours [like sleepiness or wakefulness] interact to determine the optimal physiological state,” says Hattar. Simply put, morning sunlight not only realigns the SCN clock (after it’s thrown off by everything from late-night doomscrolls and bright lamps at night to irregular schedules) but also directly adjusts rhythms that have fallen out of phase. “Bright morning light simultaneously adjusts both the clock and its downstream physiological components, producing a far more rapid and robust realignment for energy levels, hormonal balance, and other aspects of health,” he continues.
Morning sunlight exposure essentially helps keep your brain and body on the same schedule—a feat that modern life constantly disrupts. And real-world data backs it up. A recent observational study of adults in Brazil found that every 30 minutes of sun before 10 a.m. was associated with an advanced sleep midpoint (i.e., the halfway point between falling asleep and waking up, which is a marker of circadian rhythm alignment) by 23 minutes and improved sleep quality. Per Dr. Howell, sleep can feel deeper and more restorative simply by aligning your sleep schedule with your internal clock (in large part courtesy of sunshine).
Morning sunlight tips and tricks for better sleep
In order to yield the greatest results from morning sunlight exposure, heed the expert-vetted advice below.
1. The earlier, the better
According to Dr. Howell, getting outside within the first hour of waking up is ideal. While Hattar says that getting sunlight at any point of day is better than none at all, he ultimately agrees that earlier is better to anchor circadian rhythms and directly influence other factors that impact sleep, such as hunger and mealtimes.
2. Aim for at least 10 minutes
As little as 10 to 15 minutes of outdoor light exposure will suffice to anchor your circadian rhythm, says Dr. Howell, though 20 to 30 minutes or more can offer additional benefits (as suggested in the aforementioned sleep study).
Consider drinking your morning coffee or eating breakfast outdoors whenever possible. You could also do a few quick stretches and bodyweight exercises on your patio or enjoy a short stroll around the block before heading to work.
3. Don’t look directly at the sun
Save your eyes and needless pain by avoiding looking straight at the sun, especially during peak UV hours (typically from 10 a.m. to 4 p.m). “Simply being outdoors—walking or even sitting—provides sufficient light for the eyes,” says Hattar. Prefer to be as sun-safe as possible? Rest assured knowing that even being in the shade will suffice.
4. Skip the sunglasses
According to Hattar, sunglasses—and even hats that block the sunlight reaching your eyes—can undermine the effects of being outdoors since they reduce melanopic lux. (Per Hattar, melanopic lux estimates how much a given light source activates melanopsin—a photopigment found in special eye cells that helps regulate your circadian rhythm.) Aim to start your day without these accessories for at least 10 minutes before throwing them on.
5. Don’t discount cloudy days
Just because it’s not bright out doesn’t mean that you should skip heading outdoors. As Hattar explained on an episode of The Huberman Lab podcast, the natural light will still be intense enough and brighter than artificial light indoors. If possible, just aim to stay outside longer.
6. At the very least, sit by a window
Venturing outdoors is superior to sitting by a window (which filters out important wavelengths). That said, sunlight exposure via windows will still be better for your sleep and well-being over the long run than none at all. One study found that workers with indoor access to daylight via windows slept 46 minutes longer, were more physically active, and had higher vitality scores than workers in the windowless group.
7. Invest in a bright-light box
Depending on factors like seasonality and where you live, morning light might be less potent and therefore may yield less pronounced benefits. “Changes in day length can also influence your ability to achieve this morning sunlight,” says Hattar. While he confirms that natural daylight is unmatched, in some circumstances, bright light boxes can serve as a solid stand-in for natural sunlight.