We human beings are hardwired to sleep eight hours a day.

What happens when we don't do this? No matter the reason, when we deprive our bodies of sleep, there are significant physical and mental consequences.

Dr. Rafael Pelayo of Stanford University's Sleep Disorder Clinic doesn't mince words. Sleep deprivation is dangerous, he told Healthology Inc.

This is what happens to your body if it's deprived of sleep:

·        You have problems with memory and concentration.

·        You have problems finding the right word.

·        You get irritable.

·        Neurotransmitters in the brain become altered.

·        Children's growth will be stunted.

·        You become more susceptible to infection.

·        At its extreme, sleep deprivation can lead to death.

While eight hours of sleep has long been considered the gold standard for pillow time, many of us can't sleep that long as we juggle the multiple demands of work and family

But be careful how much sleep time you lose on a regular basis. Surprisingly, if you sleep six hours a night, that's considered too little and could lead to sleep deprivation, according to researchers from the Penn State College of Medicine.

 Lack of sleep isn't just a personal problem. It's an economic problem. When we don't sleep well, we cost our companies, communities, and ourselves money. Because of lack of sleep, approximately $90 billion a year is spent on lost productivity, absenteeism at work, car accidents, and sleep and stimulant medication, reports Healthology.

 Too much sleep might be as bad for you as not enough sleep. Research from the Boston University School of Medicine showed that how much sleep you get each night is correlated with your rate of mortality. In a study of 4,541 men and women, those who slept for nine hours or longer were 70 percent more likely to die over a 14-month period than those who slept seven to eight hours. Those who slept six hours or less had a 50 percent higher chance of dying.

 The optimal amount of sleep is seven to eight hours. The lead author of the Boston University study, Daniel Gottlieb, does note this: There is no direct association--that is, a cause and effect between sleep and mortality. Still, he told MSNBC that he finds the link striking and says further research is needed.

 Here's a great reason to get your zzzzz. Sleep helps us learn better. According to the Journal of Sleep Research, the best way for us to learn and understand complex material is to sleep on it. And the sooner the better. HealthScoutNews reports that when a period of learning is immediately followed by a nap, the new information is incorporated in our dreams. When this happens, it turns up again and again as we sleep. It's this repetition that helps us master the complex concepts we were just taught in the classroom and establish the new ideas in our mind. This method of learning is actually better than writing down the information, reviewing the topic in the library, and highlighting notes--all common study habits of good students.