Thursday, March 12, 2009
Photo by peasap.
Although we spend a lot of time discussing the importance of physical activity and a healthy diet, these are not necessarily the only factors affecting obesity prevention and reduction. One very interesting area that is receiving increasing attention is sleep duration, which appears to strongly influence obesity and metabolic disease risk, especially in children.
Although the exact physiological function of sleep is still unclear, the idea that sleep deprivation can lead to negative consequences is not a surprise to anyone. What is interesting, is that new studies suggest that even partial sleep restriction can result in increased risk for obesity, type 2 diabetes, and CVD. For example, adults who sleep less have been reported to have increased levels of ghrelin (a hormone which stimulates eating) and decreased levels of leptin (a hormone which inhibits eating). For a great review on this area of research by Dr S Taheri at the University of Bristol, click here. The idea that sleep deprivation might somehow affect hormones or eating patterns in the short term is not all that surprising - think of how most of us crave greasy, energy dense foods after a late night on the town. However, a recent study in Pediatrics suggests that sleep duration in childhood is a significant predictor of obesity rates well into adulthood.
In their recent study, Landhuis and colleagues from the University of Otago assessed sleep time in 1000 individuals at 5, 7, 9, 11 and 32 years of age. They report that sleep duration in childhood was a significant predictor of adult BMI, even after control for confounders like socioeconomic status and childhood BMI. Interestingly, adult sleep duration was not associated with adult BMI. Individuals who were classified as childhood "short sleepers" (less than 11 hours/night) had significantly higher BMI's than moderate (11.0-11.5 hours/night ) and long sleepers (>11.5 hours/night) at all ages. Although they did not investigate mechanisms (or suggest how to convince your kids to sleep more), the results of this paper are nonetheless very interesting, and suggest that sleep patterns in childhood (when the brain is still developing) may influence the control of energy homeostasis years down the road. These results also offer one more way that simple lifestyle modifications could help reduce the prevalence of obesity in future generations.
On a somewhat related note, Peter and I would like to publicize a joint venture of the Canadian Obesity Network (of which we are both proud members) and the Addressing Childhood Obesity through Research and Networking group. Together, they are conducting an online survey of the pediatric weight management services available for children and their families available throughout Canada. The questionnaire can be completed by any Canadian Obesity Network member (clinician, researcher or administrator) who leads a Canadian pediatric weight management program/service. The survey takes approximately 20 minutes to fill out. If you work in the pediatric obesity field, we strongly urge you to take part in this study, and to follow the results which will be available through the Canadian Obesity Network website to improve collaborations between clinicians and researchers.
To perform the survey, click here and note that Login = acorn, Password = acorn.
On a final note, my Twedometer experiment is going great! I have taken just over 20 000 steps each of the past two days, although well over half of those steps have been during my nightly training runs. It has been an interesting experience already, and I urge everyone to share their own Pedometer step counts in the comments section of our blog. To follow my own Twedometer messages on twitter, click here.
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