If you're looking to lose weight, try heading outside for 20 to 30 minutes every morning between 8 AM and 12 PM. That's the recommendation made by a recent study from Northwestern University's Feinberg School of Medicine, where researchers found that people exposed to bright light in the morning have a lower body mass index (BMI) than those who get most of their light exposure later in the day.
Researchers believe morning light may help synchronize the body's internal clock, speeding metabolic function. But what if you can't get outside during those hours? Study co-lead author Kathryn Reid, a research associate professor in neurology, says that artificial light may be beneficial – if slightly less so – as well.
"We found the magic number for light exposure is 500 lux," says Reid, adding outdoor light ranges between 1,000 lux on cloudy days and a dozen times greater on sunny days. "Most indoor light is between 200 to 300 lux, but most people don't stare at the light." Although you don't have to burn your retinas ogling at a light bulb, Reid says simply moving a bright lamp near your chair in the morning or looking out the window for a prolonged period of time can help give you good light exposure at the right time.