It is a well known fact that not getting enough sleep is a risk factor for obesity.  However, if you think you ARE one of the lucky ones who actually does get enough sleep, ask yourself if you are getting enough sleep in darkness?  A new study suggests that people who are exposed to light at night (even if they are sleeping) may be at an increased risk of carrying extra body weight, and even of having higher cholesterol!

The study, published in the current issue of the Journal of Clinical Endocrinology and Metabolism, examined body weight and cholesterol levels amongst older people (average age 73) in Japan.  Researchers went into participants’ homes and recorded exposure to light overnight, and found that those who are exposed to light overnight were 89% more likely to be obese, and 72% more likely to have cholesterol problems, compared to those who sleep in the dark.

While this study needs to be repeated in a younger population to know if these findings hold true outside of older age, there is already lots of evidence that sleep deprivation increases the risk of obesity, and that blue light exposure in particular (including from computer and mobile device screens) makes it harder to fall asleep – a habit that is particularly relevant for younger generations.

The Bottom Line:  Lights Out!

Dr Sue Pedersen © 2012 

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