Elon Musk is a genius. I'm a huge fan of what he's trying to accomplish at Tesla, and I've written often about how he uses emotional intelligence to communicate effectively.

But there's one practice of Musk's that I'm not a fan of: sending late night emails.

Musk's practice of sending out emails when most people in his time zone are asleep is well documented. One of the most recent examples: a 1:20 am email in which Musk announced a major round of job cuts.

But wait, you say. The rules have changed. We live in a world that rewards extreme hustle.

Musk himself claims to work 80 hour weeks. (That's his regular schedule; he says he works over 100 hours a week at times.) After all, as the famous CEO explained on Twitter: 

"There are way easier places to work, but nobody ever changed the world on 40 hours a week."

Others will say that writing an email at 1:00 in the morning doesn't mean you expect your people to read the message at that time, much less to respond to it. But as a team leader, you must remember that your behavior sets the example. If you regularly send late night emails or work extreme hours, you're communicating expectations, whether you want to or not.

This brings along some major problems. Here are a few of them:

It's not productive. 

Research shows that when people work too many hours, they're prone to make errors. 

For example, University of Texas at Austin professor Dawna Ballard found that social workers who were forced to work overtime not only made more mistakes when filling out reports, they were more prone to deceit--like faking visits to the homes of at-risk children.

(This research could explain why Musk himself has become prone to such high-profile mistakes in recent times.)

No matter how much you want to work, "there are just physiological barriers," Ballard told Quartz. "There's only so many hours in a day, and there are only so many hours a person can work and still function."

It's not sustainable.

Of course, there may be times when working long hours is necessary to meet a deadline or due to some other circumstance. If you do this well--by creating the right atmosphere and providing special rewards--such times can even bond your team closer together.

But expecting your people to work months (or even years) at breakneck pace is a recipe for removing all joy from the workplace. The result: higher turnover, less experience, and increased difficulty getting teams to gel together.

Additionally, as my Inc. colleague Geoffrey James pointed out, working long hours over a sustained period of time increases risk of heart disease, stroke, and early death.

So, in addition to killing your culture--you may be killing your employees, too.

It discourages diversity.

"Working at a company like this is a choice," some say. "If you don't like it, work somewhere else."

What type of workers does such a culture attract? 

Type A personalities, for sure--and plenty of youth, too. In fact, according to compensation tracking company PayScale, Tesla reported an extremely young median employee age of 30 years old. In contrast, the median age of a Tesla Model S and Model X owner is just under 54 years old, according to automotive researcher Hedges and Company.

Can you see any potential problems with a very young set of employees designing and creating a product for a much older buyer?

Diversity is about more than gender and race...it's about bringing in varying viewpoints and perspectives, all influenced by life experience. That diversity is needed to encourage innovative thinking and continued learning--and to avoid the groupthink and echo chambers that can slowly destroy a company.

Whether you're leading a team or an entire company, remember that your behavior sets the bar. Regularly sending late night emails or working extreme hours is a recipe for disaster.

In contrast, if you encourage balance and self-care, you'll increase productivity in the long run--and attract a more diverse workforce.

If you treat your employees as people with lives outside of work, you'll inspire company loyalty.

And if you set an example of hard work in a sustainable manner, you'll set a pace your people can maintain indefinitely--a major key to long-term success.

Published on: May 13, 2019
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The opinions expressed here by Inc.com columnists are their own, not those of Inc.com.