zom-bie 1 -  a person held to resemble the so-called walking dead. 2 - a person markedly strange in appearance or behavior

If this sounds like it describes you, don't panic! You're probably not undead, but there's a good chance you're sleep deprived. Lack of sleep affects many aspects of your physical and mental health, which can leave you feeling like you belong in a George A. Romero movie. Daytime sleepiness, fatigue and falling asleep immediately are the most obvious sleep deprivation signs, but there are others that may surprise you. If any of these sound familiar, it may be time to change your sleep habits or see a doctor.

Sleep Deprivation Signs

1. You're experiencing memory problems. There are three primary memory-making functions: acquisition, consolidation and recall. You acquire a memory when you learn something new, then it consolidates in your brain so that you can recall it in the future. Sounds simple enough, right? Well, not when you're sleep-deprived. Without adequate sleep, it's extra hard for your brain to complete these necessary functions.

2. You're having a hard time concentrating. Studies have linked sleep deprivation with lower alertness and concentration , which is harmless enough if all you're doing is trying to read this article, but potentially deadly if you're behind the wheel on a highway. Combined with fatigue and daytime sleepiness, this can be one of the more dangerous sleep deprivation signs.

3. You're cranky and irritable. Like a fussy baby in need of a nap, adults are also prone to crankiness if they aren't catching enough zzzz's. When you're exhausted, you're more likely to be irritated by every little thing—and that's not fun for anyone. Even worse though, studies show that sleep problems increase the risk of depression and anxiety.

4. You're hungry all the time. Two words:leptin and ghrelin.These essential hormones help regulate the appetite—signaling when you're full (leptin) and when you need to eat (ghrelin). Lack of sleep, however, throws the careful balance of these hormones all out of whack, causing ghrelin to increase while leptin drops. (Maybe this is what makes zombies so hungry for brains!)

5. You're getting sick more than usual. Your immune system relies on sleep to function to the best of its ability. Studies have shown that if you don't get enough sleep, you have a higher risk of getting sick after being exposed to a virus . Not only that, but it may take more time to recover , too. Doctors recommend between 7 and 8 hours of sleep each night to fortify the immune system.

There's no reason to continue walking around like a zombie. Most sleep problems are treatable once you identify the root cause. If any of these sleep deprivation signs apply to you, take action so you can return to the land of the living!