It's 9 a.m. and I'm sitting in a sunbeam, sipping green tea and blinking into the bright morning light. Clipped to the strap of my sports bra is a Sunsprite, a little gizmo that looks like a cross between a Fitbit and a transistor radio, which tracks how close I've gotten to the amount of light science suggests can improve mood, boost my alertness, and keep my circadian rhythms (aka my sleep-wake cycles) on track. I feel glorious—these are rays I normally miss, since the single window in my tiny apartment only catches daylight for a half-hour stretch before I wake. Wow, I think, I've really felt a little less well since I moved into this lightless place. Nothing major, but a bit more fatigued and less chipper than when I lived in a sun-soaked apartment.

If the odd health tracker on my bra strap is any indication, I'm not the only one thinking about blue light these days. Circadian rhythms are back in the techy public consciousness: A few months ago, GE released the C by GE lightbulb, which shifts from bluish in the morning to orangey in the evening; as of this year, iPhones automatically emit less blue light as the day wears on (and the latest iOs update brought us Bedtime, which sets recurring wake-up and go-to-bed alarms). Space-age-y glasses can now or block or blitz you with blue light. But a few renegades (like the Harvard brains behind the Sunsprite) insist the biggest bang will come from simply getting more sunlight in the morning. As a health junkie always on the hunt for a good shortcut, I decided to find out if the simple intervention was a magic bullet—or a load of bunk.

Lights, gadget, action!

I started, of course, with Google, and my early search results seemed promising. For starters, clinical research shows that about 30 minutes of exposure to bright light within two hours of waking can ameliorate sleep disorders, depression, and seasonal affective disorder. One study even found that areas of the United States with stronger solar intensity report fewer cases of childhood ADHD (though of course, we can't prove those residents got their dose of sunshine in the a.m.).

After a few weeks, I grew sleepy much earlier than usual, slept more soundly, and woke up less exhausted.

What's so magical about morning light? I posed the question to Sunsprite creators Jacqueline Olds M.D. and Richard Stanton Schwartz M.D.; according to them, cells in the backs of our eyes respond to light—sunshine (or fake sunshine from a therapeutic light box) triggers a chemical message to a brain structure that tells the body it's time to wake up. This structure, the hypothalamus, also shuts down the production of melatonin. Exposure to light, Olds and Schwartz add, can also kick off the production of serotonin, a feel-good chemical. So morning sunlight helps you out in two major ways: It makes you feel alert and cheery now, and it promotes sleep later, which itself is associated with a bevy of benefits (from better memory and brain development to decreased risk of diabetes, colds, heart disease, and obesity). And the whole point is to kick off the healthy domino effect ASAP upon crawling out of bed: Start the day with sun, and you'll set the stage for a good night's sleep. Hence the Sunsprite; its little screen senses light and plots your progress, lighting up in a happy dance when you hit your target (about 20 to 30 minutes in direct sun).

Do the bright thing

But can the Sunsprite strategy alone make you healthier and happier? According to Robert Rosenberg D.O., a sleep medicine physician and author of The Doctor's Guide to Sleep Solutions for Stress & Anxiety, the truth is a little more complicated. For one thing, while it's best to take in light within two hours of waking up, there's good news for those who work nights or just can't stand to get up earlier: "The idea is to get light before what we call the circadian nadir, which most people experience in the mid- to late afternoon," he says. After that, your body begins its downswing toward sleep, and bright light will just throw things off. The upshot: Take your lunch break outside or book the sunniest conference room for a midday meeting.

And bright light alone won't outdo a multitude of health sins, Rosenberg adds. You already know the other levers you can push to stay healthy and happy: Eat a balanced diet, get enough exercise, and go easy on alcohol (which increases stress hormones and suppresses deeper stages of sleep). And to keep your circadian rhythms on track, avoid sneaky sleep-disrupters like blue light before bedtime (which suppresses the normal rise of melatonin), caffeine overload, and social jet lag (i.e., losing sleep during the week and sleeping late on weekends). Morning sunlight, he says, is just one piece of the puzzle: It isn't more or less important than the others, because they're constantly interacting.

So, my expectations tempered, I turned my home into a properly lit, circadian-rhythm-friendly zone: On cloudy days, I faced a fancy new light box while I made breakfast and answered emails; on sunny mornings, I stood on the stoop until my Sunsprite hit full capacity; and I installed the app f.lux to filter blue light from my laptop screen in the evening. After a few weeks, that meh mood and fatigue did start to lift. I also noticed that I grew sleepy much earlier than usual (around 9 p.m., instead of 10 or 11), slept more soundly, and woke up less exhausted. I can’t rule out the placebo effect (or a host of other confounding factors), but I can say that I’m a believer in the daily morning light exposure effect. My challenge? Not letting other bad habits eclipse it. In my experience, a.m. and lunchtime light won't solve all your problems, but it just might make you sleepy enough at night to power down those devices, decline that night cap, and snuggle into bed at a decent hour.