If you are a leader, one thing keeping you up at night should be that things are keeping you up at night.

Sleep deprivation has a deleterious effect on almost every aspect of leadership, from charisma and management to decision-making and ethics, according to Christopher Barnes, a professor at the University of Washington's Foster School of Business. "Problem-solving and creativity are two of the big ones that get hit," Barnes says. "People struggle with self-control. They are likely to chase high levels of risk and start to ignore the potential for loss."

The result is that a whole lot of people who shouldn't even be operating heavy machinery are operating complex organizations. That's not good for employees, shareholders, or the leaders themselves, who endanger their reputations along with employee morale and productivity.

Elon Musk thrust entrepreneurial wakefulness into the news in August when he copped to working 120-hour weeks and using Ambien. Richard Branson gets five or six hours a night; ditto Jack Dorsey. Such people boast they don't need much sleep. But "almost everyone who says that is fooling himself," Barnes says. A tiny portion of the population carries a genetic mutation that reduces the toll sleeplessness takes on cognition. The rest get so accustomed to functioning at reduced capacity "that it becomes your new normal," Barnes says. "You measure your performance against that rather than how you would be after a good night's sleep."

The cost to charisma

Most entrepreneurs recognize that sleep deprivation dulls their problem-solving and decision-making skills. Such deficits, if necessary, can often be addressed by a strong, better-rested executive team. But in a startup, the main thing founders have to sell is themselves. And sleeplessness degrades their ability to express the charisma and passion that lure investors, employees, and customers to their track-record-less ventures.

In experiments conducted by Barnes and several colleagues, leaders who slept poorly were less able than well-rested counterparts to muster the kind of positivity required to inspire the troops. Their speeches, consequently, received lower charisma ratings from third-party observers. Charisma is related to passion: The entrepreneur's most valuable resource also gets lost in the drowsy fog. That hurts leaders not just with employees but also with investors, who in some contexts are influenced by passion. "It is reasonable to expect that if you give that pitch after a short night of sleep you have just lowered your odds of getting funding," Barnes says.

Fatigue also takes a toll on physical features. Research shows that when people interact with the sleep-deprived, they pay attention to droopy eyelids and mouth corners, pale skin and fine lines. Facial features are crucial to human interaction. Consequently, such distortions may have a negative social impact.

Nutshelled: Lack of sleep makes leaders look and sound bad. "People don't think, 'Wow, that guy must be working hard to be so tired,'" Barnes says. "Instead what they see is, 'This person is not especially articulate. They are not looking very smart. They are not looking very charismatic.' You are just much less impressive when you are sleep-deprived."

Sleep-deprived leaders also are more likely to act unethically, because their self-control is on mute. "Unethical behavior usually means you are facing a temptation," says Barnes, whose research shows that people may behave more or less ethically depending how much sleep they got the night before. "If you cannot exercise self-control, then you cannot overcome that temptation."

A bad role model

Sleeplessness inflicts what is arguably the greatest damage on employee relationships and company culture. Leadership experts distinguish between traits of good and bad bosses. But, in fact, one person can be both. "We overestimate how much niceness is due to personality traits and underestimate how much of it is due to dynamic moods and sleep and [changing] workloads," Barnes says. Most people can minimize how often they act like jerks, "but when you are sleep-deprived that proportion of time grows."

Barnes's research shows that sleep-deprived leaders are less patient and more antagonistic to staff. They destroy relationships. And, because their insight is dulled, they have no idea they are doing it.

Founders also have unparalleled opportunities to influence culture for good or for ill by modeling behavior. Leaders who burn the midnight oil and then fire up the Keurig four hours later create followers who sleep less (by about 25 minutes) and also less well than employees of more balanced bosses, Barnes's research finds. Those zombified hordes--like their leaders--log long days doing suboptimal work.

Creating a culture that respects sleep begins with language. "I would encourage leaders to talk about sleep as a restorative thing that will make everyone more effective," Barnes says. In such environments, late-night outreach is unacceptable. "If you need to write an email at 3 a.m., then put a delayed delivery on it so it won't go out to your employees until 8 a.m.," he says. "Then you are not setting them a bad example."

Designating a space for naps is a good idea, although hard to pull off in square-footage-challenged startups. Open floor plans further complicate matters. Barnes points out that while napping at one's desk in view of everyone would be frowned upon in the United States, in Japan it is considered a sign of dedication. "The inference is that it is probably because of all the hours you have worked," he says.

Grabbing catnaps at home is easier. Barnes favors flextime and telework options "that let people optimize their work schedule to their own circadian process." He also urges leaders to be aware of their biases around flexible schedules. Research shows that when employees set their own hours, "those who start their days early get rated as having higher conscientiousness and job performance than those who stay late," Barnes says. "Even if they work the same number of hours and the quality of work is the same." 

Strategic sleep deprivation

For leaders grappling with their own exhaustion, Barnes reiterates conventional wisdom about keeping regular bedtimes and eschewing alcohol, caffeine, and nicotine in the hours before sleep. Devices can cause trouble, because the light from screens suppresses production of melatonin, the chemical that promotes sleep. Also, devices deliver new to-do items and upsetting news. You can buy glasses that filter the light. But they do nothing to repel the digital sticks that threaten to stir up your mental beehive.

Barnes also recommends mindfulness meditations, which do quiet those bees. Recently, he has had success with online cognitive behavioral therapy tools that battle insomnia.

For entrepreneurs and other leaders who view sleep, in Musk's words, as not an option, Barnes suggests deploying deprivation strategically. Every night, the leader decides how much she will sleep. In the maelstrom of a growing business, every night she makes her default option as little as possible. Instead, Barnes says, the leader should identify times when she needs to be her sharpest: those days when she will pitch to investors or make a major decision or address a town hall. Leading up to those occasions, she should increase her sleep time, trading work for sleep. When less is at stake, she can always trade it back.

"It pains me to say that, because I don't want anyone to ever trade away sleep," Barnes says. "But we have to be realistic about the demands on an entrepreneur."