By: Thiru Kanagasabai
According to the Canadian and American Medical Associations, obesity is a chronic disease. The obesity rate is increasing in every part of the world. Over 30% of American and over 25% of Canadians are now living with obesity. Obesity is a global epidemic or pandemic that affects children and adults in both developed and developing countries. Thus, strategies to prevent, manage and treat obesity are needed to reduce obesity-associated mortality and morbidity.1
Sleep and Obesity Link
A healthy diet and physical activity are important for the prevention, management and treatment of obesity.2 But, other factors outside of the energy balance equation have also contributed to our current obesity crisis. Sleep, for instance, is one such factor. Lack of sleep and social jet lag are common features of modern society. A large portion of adults sleep less than 7 hours per night because of work–life pressures on weekdays and an active social life on weekends. Sleep duration and quality has decreased in recent decades, while the prevalence of obesity has increased. The average sleep duration of adults declined below 8 hours per night in the 1980’s, during the same time the prevalence of obesity increased.
Quantifying the association between sleep and obesity is difficult. A recent meta-analysis has found that short sleep duration increased the odds of obesity by 89% in children and 55% in adults.4 Lack of sleep lowers physical activity level and increases the craving for food rich in fats and sugars that over time increases body weight. Outside of the energy in and energy out framework, the main mechanism that explains the relationship between sleep and obesity is the regulation of leptin and ghrelin. Sleep deficiency, for instance, lowers leptin (satiety) and increases ghrelin (hunger) levels.5
How much sleep do we need?
It is not yet clear whether sleep deficiency causes obesity or vice versa. But, sleep disorders are a common feature amongst those living with obesity and so they are also less likely to get adequate (7–8 hours) sleep.6 Amongst sleep experts, however, the definition of “adequate sleep” has been a controversy for decades. Only recently, the American Academy of Sleep Medicine and the Sleep Research Society recognized this, and released a consensus statement recommending at least 7 hours of sleep per night on a regular basis for optimal health in adults.7 In children, sleep requirements vary by age.
Physical activity, diet, and sleep are important for obesity prevention, management and treatment
In the grand scheme of things, in addition to physical activity and diet, sleep has an important role to play on obesity prevention, management, and treatment. Specifically, the interacting relationships between physical activity, diet, and sleep are central for minimizing the burden of obesity. Prescribing more sleep, similar to prescribing more physical activity and a healthy diet, should become a common therapeutic strategy amongst physicians.
1. Guh, D. P. et al. The incidence of co-morbidities related to obesity and overweight: A systematic review and meta-analysis. BMC Public Health 9, 88 (2009).
2. Swinburn, B. A. et al. The global obesity pandemic: shaped by global drivers and local environments. Lancet Lond. Engl. 378, 804–814 (2011).
3. Van Cauter, E., Spiegel, K., Tasali, E. & Leproult, R. Metabolic consequences of sleep and sleep loss. Sleep Med. 9, S23–S28 (2008).
4. Cappuccio, F. P. et al. Meta-Analysis of Short Sleep Duration and Obesity in Children and Adults. Sleep 31, 619–626 (2008).
5. Taheri, S., Lin, L., Austin, D., Young, T. & Mignot, E. Short Sleep Duration Is Associated with Reduced Leptin, Elevated Ghrelin, and Increased Body Mass Index. PLoS Med 1, e62 (2004).
6. Schoenborn, C. A. & Adams, P. F. Sleep Duration as a Correlate of Smoking, Alcohol Use, Leisure-Time Physical Inactivity, and Obesity Among Adults: United States, 2004-2006. Sleep (2008).
7. Watson, N. F. et al. Recommended Amount of Sleep for a Healthy Adult: A Joint Consensus Statement of the American Academy of Sleep Medicine and Sleep Research Society. Sleep 38, 843–844 (2015).
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