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We've all faced the dilemma at some point: Should I keep studying (or working) and delay bedtime, or log out and hit the hay?

In college, I regularly stayed up until midnight or 1 a.m. studying and writing lab reports, even though my alarm went off at 5 a.m. each morning for rowing practice. It was just so tempting to stay up late when there was so much work to be done—so much work, all the time.

But while running on four or five hours of sleep in college let me finish a lot of work, I was sleepy. I nodded off during class, ate more food to keep myself awake, and became more susceptible to catching colds. I found it harder to study because I hadn’t paid attention in class. I even found myself sometimes being short-tempered toward my friends.

Sound familiar?

Today, after working in a sleep research laboratory for the past four years and becoming intimately acquainted with what the research says about sleep curtailment, I am much more inclined to shut the books, close my laptop, and crawl into bed, because the fact is that there are literally no benefits—none, zip, zero, nada—to depriving oneself of necessary sleep.

What does sleep deprivation do to your body?

Just one all-nighter alters your immune system’s functioning, similar to the way stress does. One night of sleep deprivation significantly reduces the peak of your white blood cells' diurnal rhythm, making you more vulnerable to illness and infection.

A single night of sleep deprivation results in increased blood pressure. Even a half-night of sleep loss can have the same effect for individuals who are hypertensive or prehypertensive, suggesting activation of the sympathetic system.

Your body experiences many unique changes during sleep related to growth and thermoregulation, which curtailing sleep disrupts. Satiety hormones, like leptin and , are also altered, which may result in increased hunger and weight gain.

One week of mild sleep restriction (six hours per night—a pretty typical schedule for most people, right?) causes increased secretion of proinflammatory cytokines, which can contribute to cardiovascular and neurocognitive dysfunction. (Recovery sleep on the weekends lowers these inflammation levels.)

One week of six hours per night is associated with a change in the transcription of over 700 genes, many of which are implicated in the body’s circadian rhythms, , and metabolism.

What does sleep deprivation do to your brain?

One night of total sleep deprivation reduces the coordination and speed of our ability to eye-track, as a study that simulated driving ability after insufficient sleep assessed.

The same study that found an increase in cytokines with modest sleep restriction for one week found that three nights of recovery sleep (10 hours per night in bed) was not sufficient to reverse deficits in attention and reaction time, as a simple computer task measured.

Taken together, many studies have concluded that chronic sleep loss is associated with deficits in both short- and , memory formation, , and attention/vigilance.

How can you tell if you're getting enough sleep?

You can take a test called the Epworth Sleepiness Scale. If you add your total score (out of a maximum of 24 points), you can get a sense of how sleepy you are, subjectively. (The average person scores around four or five.) There’s also an objective test of daytime sleepiness in which an individual has several 20-minute nap opportunities throughout the day. The lower the sleep latency, the greater the “sleep need.”

But sometimes you don't feel like you could actually fall asleep during the day, and yet it’s still clear you aren’t getting enough sleep. Do you find it difficult to get out of bed in the morning? Feel you need coffee to start your day? Find yourself yawning frequently? Feel sluggish, unmotivated, inattentive, or foggy-headed? Find yourself getting sick more often, or unable to perform as well in the gym? You’re probably running on too little sleep.

You have a test or project due tomorrow, and you're too stressed to fall asleep. What can you do?

If you absolutely must study in the hours before bed, make sure that you’re not studying in bright light. Light, especially in the blue wavelength, suppresses the secretion of melatonin, a hormone the pineal gland synthesizes to prepare your body for sleep. Computer, tablet, and phone screens are the worst culprits for blue-light exposure onto the retina. Consider downloading the program f.lux , which automatically softens your computer screen’s brightness at sunset. You can also try donning a pair of orange glasses to filter out blue light. (Read about the experiment I did on myself!) Try to limit bright light exposure at least one hour before bed.

, which automatically softens your computer screen’s brightness at sunset. You can also try donning a pair of orange glasses to filter out blue light. (Read about the experiment I did on myself!) Try to limit bright light exposure at least one hour before bed. Consider deep breathing and techniques to relax. I keep a MP3 and a pair of earbuds by my bed every night, just in case. Even on my most nights, following along with the voice’s commands is extremely helpful in relaxing me.

Associate your bed with (or ) only. Don’t work or study in bed. If you’re in bed paralyzed with stress and can’t fall asleep, get out of bed and find a quiet activity until you’re ready to try again. Associating your bed with will only make you dread bedtime even more each night.

If your insomnia is chronic (more than three times per week for at least three months), consider seeing a sleep specialist who may prescribe a that can suppress your body’s stress system, or refer you to a cognitive behavioral specialist for treatment.

So…should you stay up an extra hour working, or give yourself an extra hour of sleep?

I don’t think this question needs answering! Physical effects aside, sleep loss makes it difficult to learn, pay attention, and memorize information. Working late at night, to a degree, becomes counterproductive; delaying sleep cuts into our precious slow-wave sleep stage, which is associated with reduced cortisol levels and memory consolidation.

You get one body and one brain in life. Give them enough sleep—it’s the single best thing you can do to perform and feel your best every day.