Morning light is crucial for happiness. Here’s how to get it — even if you hate mornings.

Timing light exposure right helps combat seasonal depression.

Time for a winter horror story: An alarm chimes, interrupting an otherwise peaceful slumber. You extend a hand out from under the protective warmth of your blanket cocoon to silence the noise. It’s pitch black. Will you ever know warmth again? You hit snooze, remain snuggled, and try to ignore everything on your to-do list.

Instead of battling with the snooze button, many experts would suggest establishing a morning routine that includes exposure to light — whether from the sun or a light box. Morning light sets your body’s internal clock, known as circadian rhythm, helping you to fall asleep at night, and light is a common treatment for seasonal affective disorder. Also known as SAD, seasonal affective disorder is a form of depression affecting around 5 percent of American adults in the winter. While it is most prevalent in colder months, people can also experience symptoms of depression — like persistent sadness, decreased energy, and loss of interest in hobbies — in the summer, too.

The reason bright light is so beneficial as a mood-booster for those with SAD is unclear, says Norman E. Rosenthal, the psychiatrist who first identified SAD in 1984. “One idea is that the eyes are most sensitive first thing in the morning because you’ve been sleeping all night,” says Rosenthal, who is also the author of Defeating SAD: A Guide to Health and Happiness Through All Seasons.

Experts say flooding your eyes with bright light immediately after waking is one of the most effective ways to mitigate the effects of SAD, in addition to improving your quality of sleep overall. But what is one to do when their morning routine is ... lacking? Here’s some guidance on how to set a morning light habit, regardless of whether you wake up before dawn or unwillingly pry yourself out of bed at 7.

Get light as early as you can

The suggestion to get bright light “first thing” is slightly ambiguous. Can you brush your teeth first? The expert consensus is to get your dose of morning light before 8 am, says Paul Desan, the director of the Winter Depression Research Clinic at Yale School of Medicine. If you’re not an early riser or have a schedule that doesn’t accommodate a pre-8 am wakeup, get a half an hour of light when you’re able to, Desan says. (By all means go to the bathroom and complete any errands you might need to do in the morning first, says Rosenthal.) “What will happen very rapidly is,” Desan says, “over a week or two it will get easier to wake up earlier.”

For those who wake up in the dark, you might find it easier to rise with a dawn simulator. Most often this comes in the form of an alarm clock with a light that gradually gets brighter, simulating a sunrise. “Given the sensitivity of the eyes to light in the early morning,” Rosenthal says, “if you have this device that slowly turns the light on in the morning, that can work even if the eyes are shut.” Another option is an overhead light set on a timer to turn on 30 minutes before you’re due to rise, he says.

The strength of the light matters

Research has found the “optimal” dose of morning light to be 30 minutes of exposure to light that is 10,000 lux in intensity. “Ten thousand lux is a lot of light,” Desan says. “That’s like being outdoors in July.” To account for the brightness (or lack) of the winter sun for those in North America, you’ll need to spend more time outdoors to get enough light: 60 minutes at 5,000 lux (the equivalent to brightness of a cloudy day) or 120 minutes at 2,500 lux (five times the strength of bright office light).

Quality light boxes are designed to deliver 10,000 lux of intensity. Desan and Rosenthal are both proponents of light treatment using light boxes as an efficient and effective way to combat SAD. Desan’s clinic has suggested a number of light boxes that are as bright as advertised, with the cheapest being around $125. “I would buy a quality device and just start using it at the hour that you are able to get up,” Desan says.

And no, nice try, but your phone is not bright enough. “Sorry to say, I’ve measured it, but it’s nowhere near 10,000 lux,” Desan says. Looking at your phone in the morning won’t negate the positive impact of light on SAD, he says, and it won’t improve your mood either. Light from electronic devices will prevent you from falling asleep at night, so use them sparingly in the hours leading up to bed.

How to get light

In addition to light boxes, don’t underestimate the power of natural light. A morning walk or run, regardless of duration or cloud cover, is beneficial, Rosenthal says. “When you look up at the sky, there’s a vast dome from which the light is coming,” he says, “whereas the light box is really a small area. So you get a lot of your retina bathed in light from looking at the light from the sky.”

If you opt for a light box, you want to sit within about a foot of it and the light should be directed at your face. You can set it up behind your computer or laptop and check emails while getting your dose of morning light, Rosenthal says. If you use the light box too late in the day, you may have trouble falling asleep later.

Don’t stress if you can’t dedicate 30 minutes or can’t justify the purchase of a light box. Any bright light you’re able to get — as early as possible — will be beneficial, Rosenthal says.

Setting and sticking to a morning light routine is realistic, even for the most snooze-prone among us. Whether you want to bring the sun into your bedroom or are feeling inspired enough to greet the daylight outdoors, soaking in a few rays can help improve your mood and make waking up early less of a chore. (Just remember to wear sunscreen.)