It is a universally accepted notion you learn as a child: eight hours of sleep is the recommended amount needed to lead a healthy lifestyle.

Of course, then you grow up and here comes college and the SATs, and all-nighters before the final exam because you want to go through the material just one more time. Or, you know, because you were having so much fun at that party, lost track of time, and forgot about that early morning class.

As an entrepreneur, sleep can become a luxury in which most aren't able to indulge. But if you sleep less than seven hours per night, science says you're actually doing yourself harm--and it probably goes without saying, but that's not good for business. Besides the well-known effects--feeling tired and possibly overeating--you might be more likely to misunderstand social cues. The loss of nuance can, among other things, squash a nascent business deal or put relationships with everyone from employees to vendors at risk.

In particular, sleep-deprived individuals have more difficulty reading the facial expressions of others, shows a 2014 study published in Experimental Brain Research. It studied 49 healthy young adults; half slept normally and half spent a night without any sleep. (Scientists claim these results correlate with the experience of a chronically sleep deprived state.)

The next day, when the subjects were presented with images depicting various facial expressions, the sleep-deprived group took more time to recognize the emotions in all types of faces, particularly sad faces.

"If you are slower to identify what is happening and that is coupled with what we know, that you become more impulsive when sleep-deprived and risk-taking goes up, that can have deadly consequences," Namni Goel, a sleep researcher at the University of Pennsylvania Perelman School of Medicine, told the Wall Street Journal.

While Goel is referring to individuals in safety-related fields, like military personnel, police officers or airplane pilots, the combination could also jeopardize your business venture. Just imagine you're trying to negotiate a better deal with a supplier. In a sleep-deprived state you might misinterpret your supplier's expression, mistaking annoyance with serenity at a potentially hefty cost.

Another consequence of not getting enough sleep is a lower threshold for stress, notes David Dinges, a professor in the psychiatry department at Penn. "You're basically less able to emotionally cope with it," he told the Wall Street Journal. "That would explain rage responses to small things."

Other studies show people who don't get enough sleep are less emotionally expressive. Recent neuroimaging studies have found that sleep deprivation weakens the activity of the prefrontal cortex--critical for regulating emotions--while amplifying the activity in the amygdala, a part of the brain that processes emotions.

Sometimes you can't avoid those late-night early-morning combos, but you may want to reschedule important meetings or key discussions for well-rested days.