There was once a time — when I was younger — when I bragged about how little sleep I needed: “I can go on just three or four hours of sleep,” I remember telling people, thinking that it was a sign of strength. I’ve since learned that not getting enough sleep isn’t a sign of strength — it’s more of a weakness. It hurts our businesses and it could kill us.

Kill us?

Yes, that’s according to professor Matthew Walker, who is the director of the Center for Human Sleep Science at the University of California, Berkeley. His book, called Why We Sleep: The New Science of Sleep and Dreams has just been released. Lack of sleep has been linked to many diseases — from cancer to Alzheimer’s — as well as obesity, diabetes, and poor mental health.

“Once you know that after just one night of only four or five hours’ sleep, your natural killer cells — the ones that attack the cancer cells that appear in your body every day — drop by 70%, or that a lack of sleep is linked to cancer of the bowel, prostate and breast, or even just that the World Health Organisation has classed any form of night-time shift work as a probable carcinogen, how could you do anything else?” Walker said in an interview with the Guardian.

It’s a huge problem that affects us personally. And it also affects our businesses.

Not getting enough sleep diminishes our mental abilities. It clouds our decision-making. It makes us irritable. It causes us to do things that we may not have done if we were thinking with a clearer head. As business owners, our employees, customers, suppliers, partners, and their families are relying on us to make the best decisions we can so that our companies can continue not only to survive, but also to grow and provide a livelihood for all.

RELATED: Stressed? Not Sleeping? Here’s What Science Says About Sleep and How Much You Need to Be a Productive Small Business Owner

Purposely not taking care of ourselves is violating the fiduciary responsibility that we all assume when we choose to lead.

Of course, there are many people who suffer from insomnia and this is a condition that is challenging to treat. But there are others, like me, who often choose to stay up later to watch the end of the game or a movie, do more work, have another drink, or read a little more. This just pushes our bodies too far.

Happily, I changed my habits a few years ago:

  • I stopped having that last glass of wine late in the night.
  • I drank that last cup of coffee at lunch, not dinner.
  • I made it a point to get the lights out around 10 p.m.

Sure, sometimes I don’t fall asleep right away. But relaxing and deep breathing in a quiet, darkened room without any stimulants is meditative. I admit that not all nights are the same and sometimes my travel schedule interrupts this routine. But I try to close my eyes and catch some sleep on longer flights or even — and this is true — put my head down for a 30-minute catnap at my desk. I don’t think these practices replace the value of a good night’s rest. But they help. Walker suggests going even further, like alarming oneself 30 minutes before going to bed in order to begin to “wind down.”

Our jobs as business owners require us to be healthy and mentally alert. The smartest business owners I know are balanced. They are not workaholics. They understand the benefits of moderation. They work hard, but then they know when to stop. They play hard, but then they know when to rest. They take care of their bodies and their minds because they know they are not only harming themselves, but potentially the others around them if they don’t.

So listen to me: Go to bed. Trust me, the world will continue to turn and you’ll be more able to deal with tomorrow’s problems after a good eight hours’ rest.

How much sleep do you need each night to run your business successfully the next day?

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