Notes From the "Good Night" Book

Excerpts from "Good night : the sleep doctor's 4-week program to better sleep and better health," by Michael Breus...

Much of how you feel -- tired, ravenous, full, excited, thirsty, hot, cold, stressed-out -- is due to hormones getting secreted and having an impact on your mind and body. Because your metabolism is the sum of all chemical and physical changes that take place within your body, enabling its continued growth and function, your metabolism is at the mercy of these chemicals 24/7. Two hormones in particular tell you whether you're hungry or full, and whether or not you'd prefer the chocolate cake to the cottage cheese. If you're wondering whether you can control any of these hormones so you'll start craving celery and be sickened by dessert, read on.

The two digestive hormones that hold the remote control to your feelings of hunger and appetite are ghrelin and leptin. As with many hormones, these two are paired together but have opposing functions. One gives the green light that says Go and the other emits the red light that says Stop. Grelin (your "Go" hormone) gets secreted by the stomach when it's empty and increases your appetite. It sends a message to your brain that says, "I'm hungry. Feed me." When your stomach is full, the other hormone -- leptin -- sends your brain the message that says, "Stop eating. I'm done." You can thank your fat cells for sending leptin out, allowing you to push away from the table. So how do these hormones tie in to sleep?

Inadequate sleep creates an imbalance of both ghrelin and leptin. One study at the University of Chicago in 2004 showed that when people were allowed just four hours of sleep a night for two nights, they suffered a 20% drop in leptin and an increase in ghrelin. These sleep-deprived participants had a 24 percent increase in hunger and a 23 percent increase in appetite. Hunger is the feeling of wanting to eat and your appetite is the physical need to eat until full. (Think of hunger as the sensation that precedes eating.) If your brain isn't getting the message that you are full, you keep eating and eating and eating.

Sleep loss, in a sense, disconnects your brain from your stomach. Have you heard of "mindless eating"? Not only is the act of eating unconscious, but you also have a hard time controlling what you eat. The Chicago study also found that participants' appetite for calorie-dense, high-carbohydrate foods like sweets, salty snacks, and starchy foods increased by 33 to 45 percent when they slept only four hours a night.

 - page 126

...sleep loss appears to interfere with the metabolism of carbohydrates, which, in turn, leads to more fat storage and a propensity to become overweight, if not outright obese.  When sleep deprived, your body's ability to use glucose for energy drops about 30 percent.  And when the body cannot use glucose effectively, it stays in the blood and increases your risk for type-2 diabetes.  Even one week of sleep deprivation can cause a temporary diabetic effect!  How scary is that?  Of course, the sugar can't linger in the blood forever.  Such an elevated blood sugar level promotes the overproduction of insulin -- also a hormone -- which then tucks away that unused energy in the form of fat.  What's more, every time your body overproduces insulin, you become susceptible to so-called insulin resistance, at which point you can develop diabetes and no longer metabolize carbohydrates correctly.  By then, your attempts to stay lean and healthy are all the more difficult.

... growth hormone, or simply GH ... is a powerful anti-obesity hormone that decreases the rate at which your cells utilize carbohydrates and increases the rate at which they use fats (all good for weight loss).  As soon as you hit deep sleep, about thirty to forty minutes after you first close your eyes, and then several more times throughout the night in your sleep cycle, your pituitary gland releases high levels of GH -- the most it's going to secrete in twenty-four hours.

- page 130