Obesity A to Zzzzzzzzzs

Regular readers are well aware of the increasing evidence that points to a major role for sleep deprivation in the current obesity epidemic. Indeed, one of the most evident societal changes coinciding with the epidemic spread of excess weight is the significant reduction in sleeping hours – in both kids and adults.

Now a study by Orfeo Buxton and colleagues from Harvard University, published in Science Translational Medicine, shows just how profoundly sleep restriction and disruption of sleep cycles can affect your metabolism.

The experiments were designed to tested the hypotheses that prolonged sleep restriction with concurrent circadian disruption, as can occur in people performing shift work, impairs glucose regulation and metabolism.

Healthy adults were recruited to spend at least five weeks under controlled laboratory conditions in which they experienced an initial baseline segment of optimal sleep, three weeks of sleep restriction (5.6 hours of sleep per 24 hours) combined with circadian disruption (recurring 28-hour “days”), followed by 9 days of recovery sleep with circadian re-entrainment.

Not only die sleep restriction with concurrent circadian disruption markedly decrease participants’ resting metabolic rates but these interventions also increased plasma glucose concentrations after a meal, due to reduced pancreatic insulin secretion.

Nine days of recovery sleep normalized all of these changes.

Interestingly enough, a recent study by Korean researchers, published in the Journal of Sleep Research, looking at the relationship between sleeping patterns and body weight in almost 1,000 school children (48.2% boys) aged 10 or 11 found that, after adjusting for relevant confounding variables (age, sex, breakfast eating, screen time and parental obesity), longer sleep on weekdays and weekends was associated with 30% decreased odds of excess weight.

Perhaps, more importantly (and in line with the Harvard study), kids who slept little during the week but managed to catch up on their sleep deficit on the weekends also had a lower risk of excess weight.

Together these findings support the notion that sleep hygiene may be an important target for intervention in weight management and, at a population level, may well be an issue that may deserve as much attention and discussion as health eating and physical activity.

Is it time for a Canada Sleep Guide?

Calgary, Alberta

ResearchBlogging.orgBuxton OM, Cain SW, O’Connor SP, Porter JH, Duffy JF, Wang W, Czeisler CA, & Shea SA (2012). Adverse metabolic consequences in humans of prolonged sleep restriction combined with circadian disruption. Science translational medicine, 4 (129) PMID: 22496545

Kim CW, Choi MK, Im HJ, Kim OH, Lee HJ, Song J, Kang JH, & Park KH (2012). Weekend catch-up sleep is associated with decreased risk of being overweight among fifth-grade students with short sleep duration. Journal of sleep research PMID: 22494030