The Morning Light May Help You Stay Slim | WPN World People News

Spending time in the bright morning light may help you slim down, new research suggests.

The small study found that people exposed to more light earlier, rather than later, in the day tended to be leaner than their peers.

The study included 54 adults. Twenty-six were male, and the average age was 31. A special monitoring device -- worn on the wrist -- measured light exposure, sleep mid-point and duration of sleep for seven days.

Weight and height were self-reported. The researchers calculated body mass index (BMI) from those self-reported measurements. BMI is a rough estimate of a person's body fat. The participants also kept food logs during the seven days they wore the monitoring device.

The strongest association was seen in people exposed to light that was at least 500 lux, which is the equivalent of a well-lit indoor room. Outside on a sunny day provides 1,000 lux or higher, while most indoor rooms are about 200 to 250 lux.

But, the timing of the light also mattered. Those who were exposed to brighter light earlier in the day were the slimmest.

For every hour later in the day that you reach 500 lux that translates to an increase of 1.28 BMI. The earlier the light exposure, the lower the BMI.

There are a number of ways light might influence weight. One is by altering circadian rhythms -- the body's internal time clock -- to allow for better sleep. Morning light might also affect hormones that influence appetite regulation and metabolism.

Even after the researchers controlled for other potentially slimming factors such as caloric intake, sleep duration/timing and the possibility that people getting early light exposure might be more active, light exposure still seemed to account for 20 percent of BMI, according to the researchers.

Does that mean people who live in sunnier climates would be thinner than their colder counterparts? Maybe, said Zee, though they didn't include such a comparison in the current study. People tend to lose more weight in the summer, when you're getting more light earlier in the day.

Zee recommended between 20 minutes and 30 minutes of bright morning light between 8 a.m. and noon.

Whenever possible, be exposed to early light. Walk to work if you can. Bright, outdoor light will be way above the 500 lux. If you can't get outside, work near a window. If you can't get near a window, at least make sure your work environment is well-lit.

"There's some evidence here to suggest that the impact of light may influence metabolic changes and possibly play a role in BMI. And, with 67 percent of Americans being overweight or obese, it's certainly an intervention worth looking at," expert said.

Source: HealthDay News