We all know that missing sleep doesn't feel good. It makes you less able to think clearly, focus well and makes most people feel more moody (in other words, grumpy). But a lack of sleep can do more than that. It can add an inch to your waistline, and it could also cause a little bit of damage to your brain.
It can damage your DNA
For many people, lack of sleep is par for the course due to their job. Working an overnight shift often means sleeping in shifts, which is the case for a lot of doctors.
A team from the University of Hong Kong studied 49 doctors — half of whom worked overnight shifts — to determine if sleeping less had any effect on DNA. The overnight group slept on average two to three hours between calls with patients. The other group slept about seven hours a night. Researchers took blood samples for each doctor after a few days, and the results showed that the overnight doctors had more DNA breaks and less DNA repair gene expression.
But what does DNA damage exactly mean for someone's health?
Researchers said DNA damage may be linked to an increased risk for cancer and cardiovascular, metabolic, and neurodegenerative diseases. "Although this work is very preliminary, it is clear from the results that even a single night of sleep deprivation can trigger events that may contribute to the development of chronic disease," senior study author Dr. Siu-Wai Choi, told Medical Xpress.
But, the team also noted that more research is needed to determine how large a role DNA damage plays in sleep deprivation and chronic diseases.
It can affect your workday
You might need a few extra cups of coffee to feel perky on the job after a restless night. But researchers say it doesn't take much sleep loss to make your job performance falter.
Losing just 16 minutes of sleep could be enough to cause poor judgement at work and fill your day with distractions. A 2019 study published in the journal Sleep Health found that workers are more likely to fall off task after a poor night's sleep. That, in turn, raised their stress levels.
"Findings from this study provide empirical evidence for why workplaces need to make more efforts to promote their employees' sleep," said lead author Soomi Lee, assistant professor in the School of Aging Studies at the University of South Florida, in a statement. "Good sleepers may be better performers at work due to greater ability to stay focused an on-task with fewer errors and interpersonal conflicts."
It can impact how you eat
Skipping sleep also may be related to poor nutrition. A 2019 study finds that people who get fewer than the recommended seven hours of sleep per night get lower amounts of key nutrients including vitamins A, D, and B1, as well as magnesium, niacin, calcium, zinc and phosphorus.
"Our findings suggest that individuals with short sleep duration might benefit from improving their intake of these nutrients through diet and supplementation," said the lead study author Chioma Ikonte, in a statement.
The results of the study, which was presented at the annual meeting of the American Society for Nutrition, didn't say whether it was the lack of sleep causing the problem with nutrient intake or vice versa. The scientists suggest more research is necessary to see whether taking nutrient supplements might help sleep.
It can drive away your loved ones
We've all had those days when we didn't get enough sleep and felt grumpy all day long — and those around us noticed.
According to a study from the University of California, losing sleep can affect your relationship with others.
"The less sleep you get, the less you want to socially interact. In turn, other people perceive you as more socially repulsive, further increasing the grave social-isolation impact of sleep loss," study senior author Matthew Walker, a UC Berkeley professor of psychology and neuroscience, told Medical Xpress. "We humans are a social species. Yet sleep deprivation can turn us into social lepers."
The study surveyed 18 college students on nights they got a normal amount of sleep and nights when they didn't. Researchers found that students who were sleep deprived stayed between 18% and 60% further away from other people compared to students who had a full night's rest. The researchers also analyzed brain scans and found that sleep deprivation increases brain activity in a neural circuit known as the "near space network," where the brain perceives potential incoming human threats. Additionally, another circuit that encourages social interaction was turned off by sleep deprivation, worsening the problem.
However, the feeling of loneliness and social isolation doesn't have to last forever. "On a positive note, just one night of good sleep makes you feel more outgoing and socially confident, and furthermore, will attract others to you." Walker said.
Not only can lack of sleep affect your social life, but it can also make you angrier.
Research from Iowa State University says even losing just a couple hours of sleep a night can make you angrier.
"Despite typical tendencies to get somewhat used to irritating conditions — an uncomfortable shirt or a barking dog — sleep-restricted individuals actually showed a trend toward increased anger and distress, essentially reversing their ability to adapt to frustrating conditions over time," said Zlatan Krizan, professor of psychology at Iowa State.
Krizan's team divided participants into two groups — one group that continued their normal sleep routine and the other group that slept two to four hours less for two nights in a row. Both groups were subjected to different sounds before and after sleep and rated them.
"In general, anger was substantially higher for those who were sleep restricted," Krizan said. "We manipulated how annoying the noise was during the task and as expected, people reported more anger when the noise was more unpleasant. When sleep was restricted, people reported even more anger, regardless of the noise."
How sleep deprivation disrupts brain activity
A small study in 2017 looked at the cause of those sleep loss-induced mental lapses. Researchers found that sleep deprivation disrupts brain cells' ability to communicate with each other. The researchers believe that disruption leads to temporary mental lapses that affect memory and visual perception.
For the study, researchers studied 12 patients with epilepsy, who had electrodes implanted in their brains for surgery. They were staying up all night because a lack of sleep can trigger epileptic attacks. While they were up, researchers had them sort images as quickly as they could. The task grew more challenging as the patients grew sleepier.
“We were fascinated to observe how sleep deprivation dampened brain cell activity,” said lead author Yuval Nir of Tel Aviv University in a statement. “Unlike the usual rapid reaction, the neurons responded slowly and fired more weakly, and their transmissions dragged on longer than usual.”
The study was published in the journal Nature Medicine.
For the record, you can't make up for the damage done by missed sleep once it's behind you. But you can minimize damage by banking sleep (that is, sleeping more in advance of a time you know you're going to sleep less).
This is your brain without sleep
A 2014 study, published in the journal Sleep, says that pulling an all-nighter or regularly sleeping less than you should can actually damage your brain.
The study's researchers looked at specific proteins that are usually found in brain-injured people (concussions) and found that those protein levels were higher (20% higher) in people who worked all night, compared to a control group that got a good night's rest. While the levels weren't as high as the protein levels found in concussed people, the study shows that lack of sleep does real physical damage to the brain.
"It's during sleep that unimportant synapses are discarded and the important synaptic ties are strengthened," Emerson Wickwire, Sleep Medicine program director at Howard County Center for Lung and Sleep Medicine in Columbia, Maryland, and assistant professor at Johns Hopkins School of Medicine, told Fast Company. Wickwire was not involved in the study.
When you lose sleep (or worse, don't sleep at all), you brain is unable to do those important repairs and maintenance activities. Outside of it affecting your brain, the work you do while sleep-deprived is also likely to be riddled with errors. Think you are better than that? Many of the most significant disasters of the last 20 years are due to lack of sleep and ensuing human error, including the Challenger disaster, the Chernobyl explosion, the Exxon Valdez Oil spill and plenty of others (and near-misses) — and these were mistakes made by highly trained, experienced professionals. Who needed more rest than they got.
Editor's note: This story was originally published in May 2014 and has been updated with new information.