On busy mornings before work or school, seeking out some morning sun may feel more like a luxury than a necessity.
But there are many reasons why you should aim to get as much early light as possible — and they go way beyond the mood benefits that many people experience.
Specifically, morning sunshine can help you sleep better and prepare you for the day ahead, experts say. Here’s how:
The sun acts a cue for our daily routine.
“We have this term called ‘zeitgebers,’ which is basically German for ‘time-giver,’” said Elizabeth “Birdie” Shirtcliff, a research professor at the Center for Translational Neuroscience at the University of Oregon. They’re environmental cues that “help us know how to set up our daily rhythms.”
These time-givers impact many factors, including your cortisol awakening response, which is “the sort of stress hormone version of your body’s get-up-and-go [signal] in the morning,” Shirtcliff explained. It helps you wake up and feel prepared for the day. And the best time-giver in the world is the sun.
“The cortisol awakening response actually starts in anticipation of the sunrise, so it starts going up during the last little bit of sleeping. When we anticipate waking up, we have this rise in cortisol, and within the first few minutes of waking up, our cortisol levels spike by about 70% — so literally the biggest stressor your body can go through is just waking up,” Shirtcliff said.
When that peak in cortisol doesn’t happen, folks can feel tired and sluggish all day, she said.
But some of those time-giver cues are “built into our everyday events, things like the sunshine, or meal times, or when the noise on the street kicks up. All of those time-givers prepare our body to be ready for what’s about to happen,” Shirtcliff explained. “Waking up in the morning, having some sunlight — it’s a great way of helping your body’s rhythm to get ready for the day.”
What’s more, exposure to sunlight in the morning “sends signals to our brain to secrete cortisol and suppress melatonin,” Saru Bala, a naturopathic doctor based in Arizona, previously told HuffPost.
Melatonin is commonly known as the “sleep hormone.” Our bodies produce the highest amounts of melatonin during the nighttime hours and slow down during the day.
It’s important for our natural body clock.
Sunlight also plays an important role for our natural body clock, or circadian rhythm, said Dr. Sujay Kansagra, the director of the pediatric neurology sleep medicine program at Duke University Medical Center and the face behind the popular @thatsleepdoc Instagram account.
Our circadian rhythm keeps us awake during the day and helps us sleep at night, Kansagra said — and sunlight plays a major role.
“They’ve done these [lab] experiments in the past where they had somebody without any cue as to what time it was ― no light-dark signal,” he said.
The experiments found that humans’ natural body clock is actually a little longer than the 24-hour day — closer to around 24.1 to 24.2 hours, Kansagra said.
If our bodies stuck exactly to that cycle, we’d be inclined to sleep in later. But our circadian rhythm resets every morning when we expose our brains and eyes to light, and that “helps move [it] a little bit earlier. So we don’t run in a 24.2-hour cycle, we run in a 24-hour cycle,” Kansagra said.
That’s why getting morning sun is especially useful for those with early-morning obligations like work or school. “Having that early light exposure can be really beneficial to making sure your circadian rhythm doesn’t get too delayed,” he said.
Sunlight is valuable, whether you’re outside or just opening up your bedroom curtains.
When it comes to your circadian rhythm, nothing beats getting sunlight outdoors, but if your office gets lots of morning light, that can be powerful, too, according to Kansagra.
“It’s still going to be bright enough to do what it needs to do to reset your circadian rhythm,” he said. “It’s not that you necessarily have to be outside, it’s just the overall brightness.”
If regularly exercise outdoors in the morning, you’re also in luck. “Exercise in the morning is really, really good for you, especially for that energizing aspect,” Shirtcliff said.
There isn’t an exact formula for how much sun you need, but 15 to 30 minutes outdoors is probably enough, said Dr. Jawairia Shakil, an endocrinologist at Houston Methodist Hospital. If you’re getting your sun through your windows, you may need more like 30 minutes to get the benefit, Shakil added.
Timing is what’s important, so you should aim to get sunlight within the first few hours of waking up, Kansagra said. Midday light, which starts at about noon, doesn’t have the same effect on your natural body clock.
All of this is especially important for night owls and people with seasonal affective disorder.
While everyone benefits from morning sunlight, it can be even more crucial for people who tend to stay up late, since they can “easily just go to bed later and wake up much later,” Kansagra explained.
Morning sun can help night owls feel more awake in the mornings (when they’re generally sleepy) and advance their circadian rhythm so they become used to waking up earlier.
Additionally, it’s also particularly beneficial for folks with seasonal affective disorder.
“There’s actually some data out there about seasonal depression that happens when there’s not a lot of sunlight and people are not moving outside as much, and that gets negated by early morning sunlight,” Shakil said.
But whether or not you fall into these categories, getting sunlight every morning should be a part of your routine, Shirtcliff said.
You shouldn’t expect to see huge sleep cycle and energy rewards after just one morning of sunlight. But if you make it a habit, you can reap the benefits.