You can tell a soon-to-fail entrepreneur by the tired, haggard look in his eyes. Like extras from "The Walking Dead," they stumble around looking not entirely alive.

Because they aren’t.

Despite covariance in the rate of startup failures with overworked CEOs, the problem persists. Some founders are fanatical when bragging that they work 60 to 80 hour weeks. Their sense of building “sweat equity” blinds them to the sacrifices they make -- to their health, to their marriages, to their families and communities. What they mistake as a successful lifestyle is actually a massive failure.

Related: Here's Why the 8-Hour Workday Doesn't Work

Personal fatigue.

People are not designed for 80-hour work weeks, at least not over the long term.

Various studies show that we humans operate efficiently for maybe 10 hours a day, and that is if you sleep well, eat right and exercise regularly. As you will quickly see, attempting to work more than 10 hours is an exercise in diminishing returns, as it keeps you from being at your peak performance for those 10 top hours.

Most people need a solid eight hours of sleep to rejuvenate. This leaves 16 waking hours in a day. A fair amount of that time is spent in maintenance: eating, bathing, brushing teeth, walking dogs and other mundanities. Subtract also from these 16 available hours the minimal family interaction and duty time (driving kids to school), special events (seeing your doctor for that chest pain that has been nagging you), your commute time (which for most people is non-productive). Pretty soon, you may only have 10 hours in a day to do real work.

The only ways you can do more is to either work seven days a week (and that only buys you a maximum of 20 extra hours of productivity) or you skip doing those things called life. You ignore your spouse, miss your kid’s soccer game, renege on volunteer work, avoid the gym and live on fast food since you don’t have time for real food. With this lifestyle you soon won’t have a spouse, won’t see your kids because they live with your ex, are mutually ignored by people in your community -- and you will be found dead of a heart attack with a McDonald’s sack clenched in your fist.

Related: Working Long Hours Could Kill You

Why entrepreneurs work too hard.

Impatience is a universal trait with entrepreneurs. They have a vision and want to achieve it before the weekend. They also lean toward perfectionism, and pay close attention to the myriad of details in their business. Between wanting it done now and wanting it done right, they often choose to do it themselves. All of it.

But life doesn’t work that way. You don’t scale that far. Yet you start down the road of overworking yourself because you make many of the common entrepreneur mistakes:

  • You don’t prioritize: Not everything is equally important, and you let B’s get in front of A’s.
  • You don’t tackle "Tough Things First": Dread of big problems and distasteful tasks keep you from launching important initiatives.
  • You don’t delegate: Fear of other people not performing tasks the way you think they should be done causes you to micromanage or otherwise add to your workload.
  • You obsess over unimportant details: You cannot get your head out of the weeds long enough to see that the grass needs mowing.

Related: Those Long Hours at the Office Could Increase Your Risk of Heart Disease

Don’t be your own slave driver.

Overworked entrepreneurs get that way by their own hand. They are the only people who can undo the damage.

Knowing that your best performance fades after 10 hours, you need to aim for working 50 hours or less each week. I was the CEO of Micrel, a major semiconductor company, for 37 profitable years. In those nearly four decades, I put in an average of no more than 50 hours per week. I managed this by maximizing my time at work. It is much preferable to work well than to work hard. If you work well for 10 hours, it beats working poorly for 20.

Work Smarter: It sounds trite, but be smart about your every move. Remember that one good, well-thought-out decision makes things great. One bad decision requires a lot of work to undo.

Change the organization: If you find there is no way you can keep up within a 50-hour week, then you need to change your organizational design. Some work that other people should do is landing on your desk, and you need to redesign responsibilities accordingly.

Learn to let go: If you hire good people, communicate to them a clear vision, articulate the common mission and establish a solid corporate culture, you have no need to micromanage. Let these great employees do great things by doing them for you.