Sleep is more important than you could ever, well, dream. And not getting enough of it is actually pretty detrimental to your short- and long-term well-being.

“There are three pillars to health,” says Shelby Harris, PsyD, behavioral sleep-medicine specialist and author of The Women’s Guide to Overcoming Insomnia. “One is a proper diet. Another is proper exercise. And sleep should really be the third pillar.” If you don’t prioritize a good night’s rest, the first and second become more difficult to maintain, too. And that’s just one of the consequences of too-little sleep she mentions in addition to those below, noting that there are “so many” that this list is by no means exhaustive.

Before you read on in horror, however, Dr. Harris does note that worrying about the consequences of not sleeping can, for actual troubled sleepers, make it harder to get the needed rest. “It’s good to know that these consequences are an issue, and you should try to talk to a professional, but you shouldn’t constantly worry about it because for some people who are already anxious, that worry can worsen their insomnia problems,” she says.

And if you are a chronic insomniac, she notes that there are effective treatments available. “Medication is not the only answer—it is just one of the answers,” she says. “Behavioral treatments like Cognitive Behavioral Therapy are extremely effective for insomnia, and it’s a first-line treatment before we start throwing medications at people.”

There is a big difference between a troubled sleeper and someone who simply doesn’t prioritize sleep—just in terms of the amount of control one has over the situation. “There are some people who just don’t worry about sleep—they just say, ‘I’ll sleep when I’m dead, I don’t have time now’,” she says. “Those are the people that need to start putting pressure on themselves to sleep more.” In other words, if you’re not sleeping because of The Crown, you need to turn the TV off, stat.

According to Nathaniel Watson, MD, co-director of the UW Medicine Sleep Center at Harborview Medical Center, the optimal amount of sleep per night for most of us is seven hours. The exact number varies person to person, but generally speaking, if you’re consistently getting fewer than seven hours, you’re probably not doing yourself any favors; here, a few of the side effects you may experience from skimping on sleep.

This is what happens if you’re not getting enough sleep

1. Mood and mental health issues

REM sleep—one of the four stages of the sleep cycle—helps with mood regulation. So, sleep loss can cause negative mood states like irritability and crankiness. One study, which limited participants to five hours of sleep per night, showed progressive worsening of mood over the span of a week, based on questionnaire responses. Another study looked at sleep-deprived medical residents and found that their lack of sleep led to an increase in negative emotional reactions to work events as well as a decrease in the positive effects of rewarding activities.

Sleep deprivation can also lead to proper depression—several longitudinal studies have shown that insomnia is an independent risk factor for the development of depression in young adults. Research around this connection is constantly evolving; however, it’s believed that, as noted above, sleep deprivation decreases emotional resiliency and can lead to a bias toward negativity in thought and reaction which leads to depression.

Anxiety issues can develop, too, and actually this is more common in women than in men. Neuroscientists at the University of California, Berkeley, found that in brain scans, the results of sleep deprivation looked like what you’d see in an anxiety disorder. The same team also found that those who already suffer from chronic worry experience this effect the most.

2. Disrupted concentration

Focusing is difficult enough in 2020, right? Not sleeping makes it all that much worse. “So for some people, they find that they just can’t concentrate, or they can’t focus on a task or do their work as effectively as they used to be able to,” says Dr. Harris. Even watching TV—as in, actually focusing in on it rather than doom-scrolling simultaneously—could be more difficult, she explains. One reason for this, scientists at UCLA found, is that tired brain cells experience communication issues that result in spaciness. And according to research, an astounding 75 percent of people with attention deficit hyperactivity disorder (ADHD), may be experiencing a chronic underlying sleep issue.

3. Trouble remembering things

Impaired focus or concentration in turn impairs working memory (imprinting something you read or an event as it happens), so that’s one way sleep deprivation can mess with your memory. But losing sleep, especially REM sleep, also impairs memory consolidation—which is what gets memories to stick over time. If you’re not getting enough REM sleep, Dr. Harris explains, you’ll start to experience problems with short and long-term memory. There’s an additional bit of bad news here, too. Sleeping aids might help you feel asleep, but they’re not actually allowing your brain to perform the kind of sleep that aids in memory creation.

Plus, the depression which can result from a lack of sleep can exacerbate memory issues as well, both by further disrupting the focus that helps us form memory and by actually damaging brain cells in memory-related areas of the brain.

4. Blood pressure changes

If you usually get less than five hours of sleep per night, you are at an increased risk for high blood pressure, says Dr. Harris. One study shows that just one sleepless night results in higher blood pressure levels the following day. And scientists believe this may explain why a lack of sleep over time can lead to cardiovascular issues and heart disease.

5. Weakened immune system

Dr. Harris tells me that she’s seeing a lot of patients right now who are concerned about lowered immunity due to sleep issues, and it’s certainly a legitimate worry. “We find that even one night of real sleep deprivation lowers your body’s immunity,” she says. “So, you might get sick more, just because you can’t fight off germs easily.” In fact, one study took blood samples from 11 pairs of identical twins with different sleep patterns and discovered that, in each pair, the sibling who slept less had a more depressed immune system. “What we show is that the immune system functions best when it gets enough sleep,”  says lead author Nathaniel Watson, MD, co-director of the UW Medicine Sleep Center at Harborview Medical Center.

6. Increased risk of diabetes

When you’re not sleeping, Dr. Harris says your body ceases to process the hormone insulin—which is critical to blood sugar regulation—as well as it would if you were getting a solid night’s rest. This insulin resistance can then lead to the development of Type 2 Diabetes over time. “So, you have a higher risk of Diabetes [with sleep deprivation],” she explains. In fact, one (animal) study actually showed that losing just one night of sleep did as much to increase insulin resistance as six months on a high-fat diet. And according to Charlotte Martin, RDN, the high blood sugar levels that result from insulin resistance can then cause further sleep disturbances in an exhausting cycle.

7. Increased risk of dementia and Alzheimer’s disease

Sleep cleans your brain of what are called plaques—abnormal proteins that cause inflammation in the brain and disrupt nerve communication—says Dr. Harris, so if you don’t sleep, you’re going to have more plaque buildup. One study showed, in fact, that buildup increased by 5% after just one night’s loss of sleep. And that can put you more at risk for later-in-life brain-related decline like dementia and/or disease like Alzheimer’s. “When people have Alzheimer’s, we find these plaques in their brains,” Dr. Harris explains.

Chronic insomnia patients were found in one study to have double the risk of developing dementia than their more restful peers, which is a pretty significant stat. And while it’s specific to those who can’t sleep, that doesn’t mean those who are choosing to stay up are necessarily free and clear of these consequences. So, tuck in, because your brain needs a break if you want it to work for you not just tomorrow, but for the rest of your life.

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