Sleep is complicated, so say the poets and so say many of us. To some sleep is a waste of time. Why sleep when we could be living or working? To others it is akin to death. And, for others it is escape from living. To some it is the agony of insomnia—that craving for sleep but not getting it. And, for yet others sleep is welcomed rest, part of the natural rhythm of living–eating, working, reflecting, playing, sleeping.

I have always needed my sleep. As a kid I remember my father quoting Benjamin Franklin, “Early to bed and early to rise, makes a man healthy, wealthy, and wise,“ as he shooed my five siblings and me off to bed. Hearing that call to sleep I was ready. Later in college, I would go off to late night gatherings with my friends only to fall sound asleep in a corner while they partied away. They teased me mercilessly but try as I might, I couldn’t stay awake. Years later, working in a high-tech culture that was definitely anti-sleep, I vividly remember colleagues boosting about how little sleep they needed and that lack of sleep never affected their performance. I also recall feeling somewhat inadequate as I kept my silence on my need to sleep.

Science tells us sleep is good for us—for the mind, brain, and body. Sleep is not only good for us, it is as essential as eating.  Here are four good reasons why.

1. Sleep enhances memory. After a night’s sleep memory performance is 20-to-30 per cent better. After a night without sleep, people are forty per cent worse memorizing lists of words, Matthew Walker of the Sleep and Neuroimaging Lab at the University of California, Berkeley tells us.

2. Getting enough sleep keeps our cognitive abilities sharp.  On the other hand, sleep deprivation, for example getting four hours of sleep instead of seven-and-a-half or eight, wrecks havoc over time. Each night without adequate sleep adds additional burden to our cognitive facilities. We don’t think as fast, our judgment is poorer, and our reaction time slows down. I’m thinking of my colleagues espousing how lack of sleep didn’t affect their performance. What were they thinking? Or was their thinking impaired? As it turns out sleep deprived people do not know how strong their limitations are. So, there you are.

3. Getting enough sleep helps us to regulate mood.  Sleep deprived people suffer mood swings. They are irritable one minute and giddy the next. In one study the brains of sleep-deprived participants were scanned as they were shown highly negative images of torture and mutilation. Their emotional brain, specifically the amygdala, showed a strong, hyper-active response while the amygdala of the well-rested control group showed a modest, controlled response.

4. Sleep keeps our physiology functioning in balance. Our biology reads lack of sleep as a stressor leading to diabetes, heart disease, high blood pressure, and stroke. Studies at the University of Chicago have shown that getting only four hours of sleep a night for six days impairs the body’s ability to metabolize sugar putting the body in a pre-diabetic state. And, not just that! Participants were hungrier and ate more. When researchers checked the participants’ levels of leptin, they found a decrease. Leptin tells the brain that we are full. With these reduced levels of leptin, the study participants didn’t know they had eaten enough, and so kept eating.

So go ahead and sleep! It is good for you.