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.