Evan Vucci/AP Images

About a third of US adults don’t get enough sleep.

And sleep deprivation has serious consequences for your brain and body.

Many people think they can get by on less than seven to nine hours a night — the amount of sleep doctors recommend for most adults — or say they need to sleep less because of work or family obligations.

The Tesla and SpaceX CEO Elon Musk recently acknowledged in aninterview with The New York Times that his long work hours were taking a toll on his well-being and raising concerns among his friends.

That prompted Arianna Huffington to post an open letter to Muskabout his sleep schedule, telling him that he was “demonstrating a wildly outdated, anti-scientific and horribly inefficient way of using human energy.”

Musk posted his response on Twitter at 2:30 a.m. ET. “I just got home from the factory,” he said. “You think this is an option. It is not.”

Musk seems to understand that working 120-hour weeks is harmful. As Matthew Walker, a neuroscientist who’s an expert on sleep,previously told Business Insider, “The shorter your sleep, the shorter your life.”

Most adults need seven to nine hours of sleep, and kids have to get even more, though needs do vary from person to person. Some incredibly rare people can actually get by on a few hours of sleep per night, while others on the opposite end of the spectrum are sometimes called “long sleepers” because they need 11 hours nightly.

But regardless of your body’s clock, a lack of sleep will cause your physical and mental health to suffer.

Here are 30 health consequences of sleep deprivation.