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Weight Loss

Catch some rays in the morning for a lower BMI

Outdoors-y ladies, rejoice: early light exposure has been linked with a lower BMI

Just another reason to get up and go for a jog in the park before work: a new study shows getting sunlight exposure between 8 a.m. and noon is linked with a lower BMI.

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‘Light is the most potent agent to synchronize your internal body clock that regulates circadian rhythms, which in turn also regulate energy balance,’ said study senior author Phyllis C. Zee, M.D. About 20 to 30 minutes was shown to be enough to affect BMI.

To conduct the study, the researchers from Northwestern University had 26 men and 28 women around age 30 wear wrist monitors that measured light exposure for seven days. Their caloric intake was regulated, but their daily routine remained the same. The results showed that those who got light exposure earlier had lower BMIs, while those who didn’t get light exposure until later in the day had higher BMIs.

‘If a person doesn’t get sufficient light at the appropriate time of day, it could de-synchronize your internal body clock, which is known to alter metabolism and can lead to weight gain,’ said Zee.

The study, published in PLOS ONE, also noted that the influence of morning light exposure on body weight was independent of an individual’s physical activity level, caloric intake, sleep timing, age or season.

Indoor lighting provides about 200 to 300 lux, a measure of light intensity, but the study showed 500 lux to be the ‘magic number,’ or the ‘minimum threshold for having a lower BMI.’

Good news for us UK ladies—even when it’s cloudy, outdoor light is more than 1,000 lux. So provided it’s not raining, get outside for an early lunch or get off the tube a stop early and go for a stroll to work.

What tips do you have for getting a little more light in the morning?

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