Do *this* first thing in the morning if you wake up tangry (tired-angry)

By now, the term “hangry” has become indicative of those times when you’re grumpily waiting in a longggg brunch line for your Sunday avocado toast, or when the office snack drawer gets down to, like, the rolled oats. But Shawn Stevenson, health coach and author of Sleep Smarter, wants you to learn how to diffuse another mashup of emotions that might be keeping you from living your best life: “tanger” (or the garbage mood invited by one too many nights of tossing and turning).

Referencing a small study of 37 volunteers conducted in 2014, Stevenson points out that just one night of sleep deprivation can lead to an overall decrease in emotional empathy, or an ability to put yourself in someone else’s shoes.  “Also, stress hormones [AKA, cortisol] are elevated,” explains the author. “This is a normal, natural thing when you’re sleep deprived because your physiology is like: There must be a problem because this person is not going to sleep.” And if you’re all keyed up on top of being a temporarily non-compassionate human being, bad mood Susan is indefinite.

“Your internal clock is especially sensitive to the energizing effects of light in the first two hour after waking.” – Frank Lipman, MD

Fortunately, research suggests that hacking those cortisol levels (and therefore hushing your inner-Holden Caulfield) might be as simple as making sure you’re getting your vital daily dose of vitamin D. A two-year study on 1500 patients, for example, linked sleep disorders to a lack of the sun-vitamin. In the book How to Be Well, Frank Lipman, MD, says, “If your sleep patterns are in disarray, go for a brief walk in daylight as soon as you wake…Your internal clock is especially sensitive to the energizing effects of light in the first two hour after waking.”

There’s another reason that morning light might be the best to soak up, as well. The UV index—which measures the potency of the sun’s rays—will be at its lowest before 10 a.m. This isn’t, however, a call to walk around outside without sunscreen: If you decide to extend your morning walk around the block past the quarter-hour marker, you should definitely take a beat to slather on some SPF. Of course, if you don’t want to risk any exposure at all (totally fair and our beauty editors wouldn’t blame you!), you can supplement your breakfast with D-rich foods or take a vitamin D supplement, like Hum Here Comes the Sun ($20) daily.

Interestingly, while vitamin D plays a big role in mood, so too, does light itself. Research has shown light therapy to be a positive way to boost the mood, especially during the darkest months. For those who don’t have the option of taking sunrise walks, Ellen Vora, MD, a psychiatrist who’s also board-certified in integrative and holistic medicine, recommends adding a 10,000-lux lightbox ($180) to your a.m. routine (although, you should speak to your doctor beforehand), reports Be Well Health and Wellness.

So whether you live in beach weather for 365 days out of the year or barely see the sun for most of it, this simple morning routine tweak can curb tanger and probably make mornings way more enjoyable, too.

Here’s why being hangry (really!) makes you more emotional. So go ahead: Have a super-healthy snack.