Morning Sun and Lower Weight

Add early morning sun to the list of factors that might contribute to a healthy weight.

We’ve known for some time that adequate sleep is an important factor. Sunlight can have an important influence on sleep patterns, as well as hormones that regulate weight, hunger, and metabolism. Now comes a new study in PLOS ONE that finds a significant relationship between early morning light and BMI, independent of sleep and dietary patterns. It’s worth noting that any light of sufficient intensity (500 lux or more) will do. So even though the warmth of the morning sun has appeal, other sources will do.

The analysis used self-reported height, weight, and food diaries. Sleep patterns, physical activity, and light exposure — both timing and intensity — were measured by an electronic monitor on the wrist. The study design was cross-sectional, which prevents any definitive conclusions about causality. And of course, self-reported height, weight, and food logs all represent sources of error. Nonetheless, the statistical relationships are robust and the authors conclude:

Light is a powerful biological signal and appropriate timing, intensity and duration of exposure may represent a potentially modifiable risk factor for the prevention and management of obesity in modern societies.

Maybe Ben Franklin was onto something with his early to bed, early to rise advice.

Click here to read more in the LA Times and here to read the study itself.

Early Morning, photograph © TEngland Photos / flickr

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4 Responses to “Morning Sun and Lower Weight”

  1. April 04, 2014 at 9:29 am, deirdre said:

    I was very excited when I read a popular press article on this same story. I do love the sun. I was so excited I downloaded the article and then, because I was confused, I emailed the authors. Guess what? There is not one mention of sun light in the research article. In fact, it is only assumed that the light exposure – because of the intensity – is from the sun. I know that the morning sun makes ME feel better but to be clear, the researchers did not study time in the sun, per se.

    • April 04, 2014 at 11:55 am, Ted said:

      Excellent point, Dierdre. Their evidence is for early morning light exposure of sufficient intensity. Morning sun qualifies, but other sources are not excluded by this study. More research is needed…

  2. April 05, 2014 at 11:58 pm, Weight Loss said:

    Getting a good dose of early morning light on a regular basis appears to be a simple but remarkably effective way of maintaining a healthy weight

    • April 06, 2014 at 4:59 am, Ted said:

      Cause and effect yet to be proven, but there’s a strong relationship.