Sun slim

Mornings can be a challenging time. As the mists of sleep linger there is muesli to be masticated, fashion decisions made, daily diaries to be consulted, and bathrooms to be competed for (unless you are living alone in which case there is the cat to be fed). Yet if you can find time amid this formidable exercise in logistics to expose yourself to some morning sun it could just be that your waistline and your weight will be the better for it.

In the new study subjects wore a wrist monitor to monitor their exposure to light, and also their sleeping patterns, over the course of a week. Subjects also kept food diaries so the researchers could measure their kilojoule intake. What the researchers were looking for was any association between the timing of the exposure to sunlight, the duration of that exposure, and Body Mass Index (BMI).

What emerged was that it was not so important how much light exposure a person experienced but when that light exposure occurred. The results showed that people who has most of their exposure to light earlier in the day were also more likely to have a low BMI. Additionally, the relationship was linear in that the earlier the exposure occurred the lower the BMI.

The relationship between light and BMI was only there when the light intensity was between 170 and 850 lux. Even on a cloud day during the middle of the day the light intensity is at least 1000 lux. So it is morning light that is effective. This effect is probably there because in the mornings we are exposed to larger amounts of “blue” light which has a significant influence on the body’s circadian system.

So there’s part of your formula for a flourishing life; rise, salute the sun, and be fine.