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Study: Exposure To Morning Sunlight Helps Managing Weight

Posted by samzenpus on from the here-somes-the-sun-there-goes-the-pounds dept.

jones_supa (887896) writes "A new Northwestern Medicine study reports the timing, intensity and duration of your light exposure during the day is linked to your weight — the first time this has been shown. People who had most of their daily exposure to even moderately bright light in the morning had a significantly lower body mass index (BMI) than those who had most of their light exposure later in the day, the study found. It accounted for about 20 percent of a person's BMI and was independent of an individual's physical activity level, caloric intake, sleep timing, age or season. About 20 to 30 minutes of morning light is enough to affect BMI. The senior author Phyllis C. Zee rationalizes this by saying that light is the most potent agent to synchronize your internal body clock that regulates circadian rhythms, which in turn also regulate energy balance. The study was small and short. It included 54 participants (26 males, 28 females), an average age of 30. They wore a wrist actigraphy monitor that measured their light exposure and sleep parameters for seven days in normal-living conditions. Their caloric intake was determined from seven days of food logs. The study was published April 2 in the journal PLOS ONE. Giovanni Santostasi, a research fellow in neurology at Feinberg, is a co-lead author."

8 of 137 comments (clear)

  1. correlation does not prove causation by Todd+Palin · · Score: 5, Interesting

    Could it be that the fat people are just lazy and get up later, and don't get outside early. Maybe fat causes people to get less light in the AM. See the problem with the headline?

    1. Re:correlation does not prove causation by Travis+Mansbridge · · Score: 4, Insightful

      True, but the summary does say "..independent of an individual's physical activity level, caloric intake, sleep timing, age or season."

      In any case causation is not proven, and this is a pretty small sample anyway.

    2. Re:correlation does not prove causation by bluefoxlucid · · Score: 5, Funny

      You're not reading this right. The solution is to get up later, when the sun is up, so that you are immediately exposed to sunlight early in the day.

      --
      Support my political activism on Patreon.
    3. Re:correlation does not prove causation by The+Grim+Reefer · · Score: 4, Funny

      I have a skylight in my bedroom. I'm going to start opening the blind on it in the morning and go back to sleep for an hour or two. And eat cake and ice cream for breakfast, lunch and dinner. That should drop my BMI by 20% according to the summary.

    4. Re:correlation does not prove causation by nbauman · · Score: 5, Insightful

      If they really wanted to find out whether sunlight affected weight, they would have done a randomized, controlled trial.

      They would have randomly assigned half the people to getting exposed to sunlight early, and the other half to getting exposed to sunlight late.

      Instead, they let the subjects go their merry way and simply measured their exposure to sunlight during the day.

      These kind of studies give spurious results. For example, suppose the ones who are exposed to sunlight in the morning are getting up early to start their day jogging.

    5. Re:correlation does not prove causation by clovis · · Score: 5, Insightful

      If they really wanted to find out whether sunlight affected weight, they would have done a randomized, controlled trial.

      They would have randomly assigned half the people to getting exposed to sunlight early, and the other half to getting exposed to sunlight late.

      Instead, they let the subjects go their merry way and simply measured their exposure to sunlight during the day.

      These kind of studies give spurious results. For example, suppose the ones who are exposed to sunlight in the morning are getting up early to start their day jogging.

      Well, no.
      You don't begin a line of inquiry with a randomized, controlled trial. You begin with a study to see if there may be a correlation.
      Why? If there's no correlation in a study, then there's no reason to spend the (much greater) money on a randomized trial.
      If there does appear to be a correlation, you report it so that you (and others) may pursue the inquiry further.

  2. Re:Benjamin Franklin by The+Grim+Reefer · · Score: 5, Interesting

    Early to bed and early to rise, makes a man healthy, wealthy, and wise.

    I don't know about healthy. But late to bed, late to rise, seems to make you more intelligent and wealthier That study looked at 1000 people, rather than 54. If both studies are accurate, it looks like you can be smart, fat, and rich, or healthy, poor and stupid.

  3. Re:Benjamin Franklin by causality · · Score: 4, Funny

    The early bird catches the worm. The early worm gets eaten.

    The second mouse gets the cheese.

    --
    It is a miracle that curiosity survives formal education. - Einstein