Thinning Sleep

We have all heard of beauty sleep. Is there such a thing as thinning sleep? While I was working overnight at the hospital I was wondering if a disruption in circadian rhythm may effect metabolism or how lack of sleep may attribute to weight gain. During these "graveyard shifts" I have noticed that there is always tons of junk food in the nursing stations and I tend to crave sugar. It is possible that we crave sugar both at night and during the day to keep us awake. We have all been known to experience an energy crash in the mid afternoon which triggers a trip to the coffee and sweet stand. Recent research has identified two important hormones that appear to play a role in the association between sleep and metabolism.

Ghrelin is a hormone that is produced in the gastrointestinal tract. It is the culprit for our stomach growling to notify us of hunger. It turns out that lack of sleep, or even restless sleep, increases our levels of ghrelin hormone throughout the day. Studies have shown that people with ineffective or lack of sleep have higher circulating levels of this hormone and tend to consume more high density carbohydrates. Therefore, they tend to be more overweight. We all know if we get less than 7-8 hours of sleep but many of us don't know if we have sleep disorders that effect our quality of sleep. A common sleep disorder is obstructive sleep apnea that is basically a cessation of breathing multiple times throughout the night due to relaxation of the neck muscles that protect our airways. This is a known risk factor for not only obesity but also heart and lung disease. People that snore heavily, have large necks or are overweight may have obstructive sleep apnea. This can be diagnosed with a sleep study and is a treatable disorder.

The other hormone of interest in this area is called Leptin. Leptin is produced by fat cells that are responsible for telling us when we are full, essentially the opposite effect of ghrelin. Interestingly, levels of circulating leptin have been found to be lower in people that are not well rested. Therefore, they can eat more without feeling the sensation of fullness. We are all starting to hear about insulin resistance as a cause of type 2 diabetes, well, now there is discussion about leptin resistance. This may be your first introduction to leptin but it is certainly something that you will hear more about in the future.

With all of life's stresses it can be very difficult to slow down our minds and bodies at the end of the day to ensure a restful nights sleep. Things such as breathing exercises, avoiding caffeine late in the day, and good sleep hygiene may help us to get the sleep that we need to keep our metabolism in check.

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