Not Catching enough Zzzzz’s?
You could be at risk for gaining more LB’s!
By Morgan Davis, RD, LDN
The link between sleep and obesity is not a novel topic. Multiple research studies have illustrated the association of adequate sleep and weight management. Now, much of the research is geared toward exploring the reason for this association
Sleep is our body’s opportunity for revitalization. We need sleep to refresh ourselves, both mentally and physically. Adults need an average of seven to nine hours of sleep per night. Does that sound like a lot to you? Well, then you are not alone. According to the National Sleep Foundation, the average adult sleeps only 6.5 hours per night. Increasingly busy lifestyles, television, caffeinated beverages, alcohol and stress can all be reasons that we don’t reach that coveted 8 hours of rest. But can cutting your sleep time short be the reason you are having a hard time reaching, and maintaining, your goal weight?
One of the explanations for lack of sleep and weight gain focuses on the hormone, grehlin. Grehlin, aka “the hunger hormone” is relatively new in the science community. Only recently discovered in 1999, grehlin is still the only known hormone circulating in the blood stream that stimulates hunger and promotes food intake. After eating, grehlin decreases in proportion to the size of the meal. Then, as the time since your last meal or snack passes, grehlin levels rise again, and the feeling of hunger creeps in. Some studies have shown higher circulating grehlin levels in people who had chronic inadequate sleep.
Alternately, leptin is one of several peptides that has an anorexigenic effect, meaning it decreases appetite and provides signals to stop eating. Leptin, aka “the fullness hormone” is joined by a multitude of other peptides that tell us to stop eating, including Insulin and cholecystokinin. The concentration of these circulating hormones increases after a meal. Some studies have shown that these hormones are decreased when sleep is less than adequate. This would cause a reduced feeling of fullness.
Yet another explanation for the correlation between sleep and weight focuses on some of the key hormones in regulating glucose metabolism. Studies have shown that poor sleep quantity and quality disrupt the normal production of insulin, cortisol and glucagon. The pancreas becomes overworked and the body starts to become resistant to the amount of insulin being produced. Insulin resistance is a strong indicator of diabetes risk. Poor blood sugar control has been linked with excess weight, leading to another possible mechanism for weight gain from inadequate sleep.
And possibly the simplest explanation of them all- with poor sleep quality/quantity, the body will be physically and mentally tired. These feelings of fatigue can quite possibly be misinterpreted as feelings of hunger leading to increased food intake and poorer food choices
So why should you be concerned with all this science if the exact explanation is unclear? Though the current research is conflicting as to the underlying process leading to weight gain, the majority of studies have come to a very similar conclusion: study participants sleeping less than 5 or 6 hours per night consumed an additional average of 250 calories per day, compared with those who slept at least 7 hours. The real problem is that there are no increases in energy expenditure by staying awake for the extra hours; therefore, the extra caloric intake leads to weight gain over time.
And here is the real kicker. We see that inadequate sleep can lead to weight gain. However, obesity can also lead to poor sleep quality. There is a viscous cycle at hand. Carrying extra weight is a significant risk factor for developing forms of sleep-disordered breathing, such as obstructive sleep apnea (OSA). In this condition, there will be pauses in a person’s breathing during rest. This disrupts the sleep cycle, and OSA has also been associated with leptin resistance, further decreasing the body’s ability to regulate intake. What is the best method for improving symptoms of sleep apnea and other forms of sleep-disordered breathing? Weight loss.
Despite the actual hormonal explanation for appetite and intake, and regardless of whether decreased sleep leads to weight gain in a specific individual, it is safe to say that adequate sleep is an important factor for one’s overall health. Adequate sleep can improve memory, attention and mood, keep hormones within normal range, promote immune function, maintain blood glucose regulation, and possibly keep our hunger and fullness hormones where we need them to be for healthy weight maintenance. So, in addition to maintaining 30-60 minutes of physical activity on most days, and eating a lean, well-balanced diet, aiming for a minimum 7 hours of quality sleep is key for good health and wellness.
Want to learn more about these topics? Check out the following resources:
Associated Professional Sleep Societies, LLC. Sleep. J Sleep and Sleep Disorders Research. Vol 34, 2011. http://www.journalsleep.org/resources/documents/2011abstractsupplement.pdf
Hillman, J; Tong, J; Tschop, M. Ghrelin Biology and Its Role in Weight-Related Disorders. Discovery Medicine, June 2011. http://www.discoverymedicine.com/Jennifer-B-Hillman/2011/06/17/ghrelin-biology-and-its-role-in-weight-related-disorders/
Kondracki, N. The Link Between Sleep and Weight Gain. Today’s Dietitian, vol 14 No. 6, 48-53.
National Sleep Foundation. http://www.sleepfoundation.org/
Touma, C; Pannain, S. Does Lack of Sleep Cause Diabetes? Cleveland Clinical Journal of Medicine. Aug. 2011, vol 78. 549-558 http://www.ccjm.org/content/78/8/549.full
