The feeling is fleeting, but as good as it gets.

You're not quite awake, not quite asleep. Somewhat conscious and cognizant, but far from fully so. Perfectly peaceful and contented because you've been lovingly cradled in the arms of Morpheus all night long.It's delicious bliss - until a hailstorm from your alarm clock transforms your ears into a tin shed. At that moment, you'd do anything for Morpheus to scoop you up in his arms again.Unfortunately, many people have terribly short memories when it comes to Morpheus's magic, so that next night they delay, delay, delay meeting him again. They go to bed too late and begin the following day in the worst of ways.Sleep deprived.When Phyllis Zee, the medical director of the Sleep Center for Circadian and Sleep Medicine at the Northwestern University Feinberg School of Medicine, spoke to journalist Rex W. Hupke about America's sleep habits, she said, "We're not prioritizing our sleep. We're not maintaining a regular sleep and wake time. If you have something you need to do, you're likely just to curtail your sleep."If you're like most Americans, you see that willingness to sacrifice sleep as part of what makes this country great. As Zee later stated in the interview, we tend to equate being well-rested with being lazy.Likewise, we also equate being grumpy and in dire need of caffeine with being sleep deprived. But recent research has discovered many other negative consequences to add to that equation.Like an increased risk of high blood pressure, heart disease, type 2 diabetes, and obesity.Those health problems, however, take weeks or months, possibly even years to manifest themselves. The point to today's column is that your health is affected immediately - and possibly even lethally - by insufficient sleep.The immediate negative effects occur because a lack of sleep alters your production of two hormones that help regulate appetite and one that increases your blood sugar level.About 25 years ago, research revealed that the production of leptin signals the brain that food consumption can stop. Subsequently, several studies have found a correlation between a lack of sufficient sleep and decreased production of leptin.Near that time, researchers also discovered that the production of ghrelin signals the need for food. Ensuing studies determined that a lack of sleep increases ghrelin production.Well before those discoveries, researchers recognized that cortisol is secreted when you sense danger. If, for instance, you're awakened at night by the noise made by a burglar breaking into your house, cortisol is immediately secreted.As a result, your heart races, your blood pressure increases, and your blood vessels dilate, preparing you for the fight - or flight.Cortisol also triggers the fat stores to release extra blood sugar for extra energy, breaks down muscle for back-up energy, and suppresses your immune system.But what if the noise was just the furnace? What if there's no fight or flight?Insulin is then produced to take the unneeded extra energy, including the broken down muscle, back to the fat stores.So if you release cortisol unnecessarily, you're far more likely to gain weight and get sick. And guess what? Studies have shown that those who get less-than-sufficient sleep produce more than the normal amount of cortisol.Because hormones besides leptin, ghrelin, and cortisol affect body weight and all hormone production differs from person to person somewhat, it's hard to calculate to what degree a lack of sleep increases body weight. David F. Dinges, PhD, director of the Unit for Experimental Psychiatry and chief of the division of Sleep and Chronobiology at the Perelman School of Medicine at the University of Pennsylvania, however, believes it's considerable.In a 2015 Medical News Today article, he estimated that when adults are sleep deprived, they eat an additional 500 calories a day.Last month, researchers at the University of Pennsylvania confirmed his estimate with a study of 36 healthy adults who slept either four hours or 10 hours a night for five days. Additionally, the lack of sleep reduced resting metabolism in subjects by 50 to 60 calories per day.Statistics like those might just motivate you enough to ensure you get at least seven, preferably eight, hours of sleep a night.If you live long enough to make the change.No, I'm not engaging in yellow journalism. I'm simply introducing the latest report released by the AAA's Foundation for Traffic Safety that states vehicle-crash risk increases dramatically in those sleep deprived. And sleep deprived doesn't mean the red-eyed doctor in residency who just pulled an all-nighter.It's true if you sleep as little as one hour less.Then your chance of being in a crash nearly doubles, an increase significant enough to for the AAA to claim the reduction "may have deadly consequences."Get less than four hours of sleep one night and then drive a vehicle, and your chance of an accident increases by 11-fold for the next 24 hours, making that form of transportation also a form of Russian roulette.