You’ve probably heard that you need to get your eight hours of sleep a night, but how often do you actually get that? Most people get by on six or seven hours, or sometimes even less. And sometimes this feels fine. But this might be even more harmful than we thought.

Sleep deprivation can be really serious—even as serious as some diseases, like cancer. That’s because frequently not getting a full night’s rest is linked to a higher risk of actually getting cancer, according to a study published in the Journal of the National Cancer Institute. Research has shown lack of sleep can lead to colon or breast cancer in particular.

Being sleep impaired can also have a negative effect on your heart, a study published in Sleep Medicine Reviews found. Blood pressure and risk of heart disease can both increase the more sleep deprived you are.

There’s more bad news. If you ever noticed that on a day you were particularly sleep deprived, you can’t remember much that happened that day, there’s research to back that up. One study published in the Journal of Clinical Endocrinology and Metabolism (among others) have found that adults running on empty have find it difficult to remember words they’ve learned and are sometimes unable to improve skills that were learned on that day.

It makes sense then that when you’re regularly not sleeping, you risk long-term memory loss. Frequent poor sleep has been shown to lead to structural changes in the brain that are associated with impaired long-term memory. On the contrary, the more sleep you get, the better your memory.

Additionally, lack of sleep does damage to your skin. Skin actually can’t heal as quickly or as well when you’re sleep deprived as it can when you’ve gotten enough shuteye, according to a study in Clinical and Experimental Dermatology. This can lead to wrinkles, age spots, and saggy skin.

What’s more, have you ever noticed when you didn’t get a full eight hours, you’re super hungry? Like the you want to eat everything—especially junk food—kind of hungry? You’re not imagining it. It’s common for those who frequently get poor sleep to crave high-calorie foods throughout the day, research shows—and give in to that temptation. Why? Sleep deprivation results in hormonal imbalances, and experts believe these hormonal imbalances make you crave that kind of thing. That leads us to the fact that sleep deprivation is linked with a high body mass index and obesity, since you undergo hormonal imbalances from lack of sleep.

You also might notice that you’re pretty irritable on a handful of hours of sleep—you’re more easily annoyed by things, you might have a short fuse, and you’re quick to snap. That’s why when little kids throw a tantrum, the parent usually says something like “you need a nap.” This applies to adults as well!

There are tons of other ways sleep has a negative effect on your health—from being more susceptible to catching a cold, to making you clumsy and increasing your risk for depression. But we’re going to stop, since, well, it’s depressing. Make sure you’re getting at least eight hours of sleep a night. Here are some easy ways to help you fall asleep.

Did you know sleep deprivation could be so detrimental to your health? How many hours of sleep do you usually get a night?