Everyone knows that it’s important to get enough sleep, but you may not realize just how many things can go wrong when you don’t.

Here are unfortunate risks of partial and total sleep deprivation, some more common than others.

Scientists don’t yet know exactly why sleep deprivation leads to headaches, but it’s a connection. Doctors have noticed for more than a century that Migraines can be triggered by sleepless nights, and 36 to 58% of people with sleep apnea wake up with “nondescript morning headaches.”

Sleep deprivation is associated with tunnel vision, double vision, and dimness. The longer you are awake, the more visual errors you’ll encounter, and the more likely you are to experience outright hallucinations.

Scientists are just beginning to investigate the relationship between sleep and cancer, and different kinds of cancer behave differently. But since disrupted circadian rhythm and reduced immunity are direct results of sleep deprivation, it’s no surprise that preliminary research seems to indicate that people who don’t get enough sleep are at increased risk for developing certain kinds of cancer, most notably colon and breast cancers.

Another study reported higher marital happiness among women with more peaceful sleep, although it’s hard to say whether happy people sleep better, better sleep makes people happier or most likely some combination of the two. Insomniacs are also twice as likely to develop depression, and preliminary research suggests that treating sleep problems may successfully treat depressive symptoms.

When researchers kept people awake for 88 hours, their blood pressure went up, no big surprise there. But even subjects who were allowed to sleep for 4 hours a night had an elevated heart rate when compared to those getting 8 hours. Concentrations of C-reactive protein, a marker of heart disease risk, increased in those fully and partially deprived of sleep.