It's a holiday weekend. Planning to catch some extra zzzzs? You know you need them. We'd all like to get the prescribed seven to nine hours of sleep each night, but let's face it, it often doesn't happen. And whether it's because of insomnia, over-booked schedules, or the modern status symbol of exhaustion, perpetual daytime drowsiness can seem like something we just have to suck up.
But plenty of research suggests sleep deprivation isn't something to shrug off. It can have serious, long-term effects on your health and cognition. Here are some of the ways that getting less than six hours a night of shut-eye (something like 30 percent of adults report is the case) for any prolonged stretch of time takes a toll.
1. It Can Literally Change Your Genes.
A 2014 study showed that just one week of insufficient sleep resulted in changes to the expression of over 700 genes. It's not clear what all the affected genes are responsible for, but some of them are known to relate to regulation of metabolism and stress response. The study also found, understandably, that when they were awake, participants showed more lapses in attention.
2. It Can Make You More Likely To Have A Stroke.
And by a sizable amount, too. Researchers found that in middle-aged or older people who don't exhibit other stroke risk factors—they're not overweight and they don't have a family history of strokes—regularly getting less than 6 hours of sleep a night made them four times more likely to suffer a stroke. The study involved tracking 5,666 people over the course of three years.
"A lot of people say that when things get stressful and schedules get tight, sleep is the first thing to get sacrificed," study researcher Megan Ruiter, of the University of Alabama at Birmingham, told the Huffington Post. "It turns out that it's a lot more problematic than we previously realized."
3. It Can Increase Your Appetite And Make You Retain Fat More.
In 2012, a group of scientists reviewed 18 different studies published between 1996 and October 2011 relating to weight gain and partial sleep deprivation (meaning, consistently sleeping less than the recommended amount as opposed to pulling a single all-nighter). They found consistent evidence that lack of sleep increases the hunger-stimulating hormone ghrelin, and decreases the hormone leptin, which is key for energy balance and food intake. Both changes are liable to make you hungrier throughout the day.
This is supported by another 2012 study (with an admittedly small sample size) that found 16 men of normal weight selected larger portion sizes for themselves after nights of deprived sleep, suggesting "that sleep deprivation enhances food intake regardless of satiety," study researcher Pleunie Hogenkamp, of Uppsala University, said in a statement.
4. It Can Ruin Your Ability to Make Healthy Choices.
An expansive study conducted by researchers in Denmark and Finland followed 35,000 adults over eight years to track how insufficient sleep impacted their lifestyle. They found that the more regular sleep participants received, the more likely they were to make healthy choices. For example, regular sleepers who smoked at the start of the study were more likely to have quit smoking four years later, compared to smokers who either shortened their average sleep duration over the course of research or experienced an increase in sleep disturbances.
Similarly, inadequate sleep correlated to an increased risk of taking up high-risk alcohol consumption, becoming physically inactive (among the initially physically active), and becoming overweight or obese.
5. It Can Deplete Your Memory-Making Ability.
But then again, so can too much sleep, according to a study out of the Harvard-affiliated Brigham and Women’s Hospital in Boston. The researchers interviewed a group of women about their sleep habits in 1986 and 2000. Over the course of a six-year period after that initial interview, the participants were asked about their memory and thinking skills. Women who regularly slept five hours or fewer a night performed worse than those who slept the recommended seven to eight on brain performance tests—although, so did the women who slept nine or more hours. The researchers concluded that both too much and too little sleep will mentally age someone two years beyond their actual age.
It's not clear what the internal mechanism is that relates sleep to brain function, but scientists theorized that it might have something to do with the fact that people who are regularly sleep deprived are more likely to have high blood pressure, diabetes, and narrowed blood vessels (another reason to get a full night's worth) which could decrease necessary blood flow to the brain.
6. It Can Cause Bone Density Loss.
At least in rats. A 2012 study published in the journal Experimental Biology and Medicine showed that sleep-deprived rats had numerous signs of osteoporosis: decreased bone mineral density, less fat in their bone marrow, and double the amount of megakaryocytes (bone marrow cells that produce platelets), compared to rats who slept normally.
7. It Can Make You More Anxious.
You know lack of sleep makes you crabby the next day, but a 2012 study showed specifically how sleep deprivation increases activity in the portion of the brain that controls the anticipatory response. In small doses, the anticipatory response helps us prepare for upcoming events in our lives, but people who suffer from anxiety have an overactive sense of it. The admittedly small study showed that for 18 young adults, staying awake for 24 hours significantly amplified anticipatory activity in the brain, particularly among people who were already anxious to begin with.
8. It Impairs Your Ability To Develop Normally.
Human infants sleep a ton—just like fruitfly infants. And, at least in the flies, diminishing this sleep early in life has long-standing negative affects. A 2014 study looked at first, why infants sleep so much and secondly, what happens if they don't. Fruitflies that were genetically modified to sleep less when they were young grew up to have a certain section of their brain noticeably smaller—specifically the region responsible for the development of courtship behavior. It's not clear if the correlation to humans is exact—do restless babies grow up to be boorish dates?—but it shows that early sleep deprivation permanently stunts brain development.
9. It Increases Your Chance of Mortality.
How bad is not sleeping? It makes you more likely to die sooner. A 2010 study followed 1741 men and women for 10 years (women) or 14 years (men) and found that for men, insomnia—sleeping less than 6 hours a night regularly—translated to a 21 percent higher mortality rate. Women had a more negligible 5 percent higher mortality rate. This result was determined after adjusting for factors like age and race, as well as things that could also result from lack of sleep—smoking, alcohol use, depression, and a higher BMI. In other words, it's not just that insomnia causes men to adopt unhealthy habits that lead to premature deaths. Not sleeping itself is killing them.