The Biggest Hidden Cause of Burnout (and What to Do About It) Hint: Burnout has nothing to do with overworking.

You're running on empty at work and getting dangerously close to burning out. Better rest up, scale back your hours, and set some healthier boundaries, right?

Maybe not.

Burnout is the product of chronic and unmanaged workplace stress, so it's natural to assume that overworking is the primary cause. Casually mention your impending burnout to a friend or colleague, and nine times out of 10, they'll suggest you take some time off, catch up on your sleep, and maybe even talk to your manager about a reduced workload.

Related: These Three So-Called Stress-Relievers Are Actually Making Your Burnout Worse

But what if we're missing something?

There's a hidden cause of burnout that we don't talk about much. And it has nothing to do with overworking. Shocker, right?

It's feeling a lack of control -- over your work assignments, over workplace relationships and even over the future of your career.

As a career change coach, I have many clients who are on stress leave from burnout, and many others who are getting dangerously close to that point. And in very few cases, it's because of overworking. Don't get me wrong, that's certainly an issue for some, but the people I work with are burning out because they feel powerless and trapped, like they have no control over their work.

This feeling of powerlessness is the main reason why so many people find themselves getting sick, going on stress leave and often eventually quitting.

The Mayo Clinic defines burnout as a combination of physical and emotional exhaustion, and an erosion of identity at work. There's a heavy emotional component -- and nothing evokes a more emotional response than feeling powerless.

Here are three ways feeling a lack of control may be contributing to your burnout or the burnout of your employees -- and what to do about it:

Related: 4 Science-Backed Ways to Prevent Burnout

1. I feel like I have no control over my work.

This may occur if you have no autonomy over your work assignments or no freedom or flexibility in the direction of your work, either in your day-to-day tasks or the larger trajectory of your work. One of my clients was recently "rewarded" with a promotion she didn't want, doing work she doesn't enjoy. In a matter of months, she went from being a top performer to being on sick leave because of burnout -- not because of an excessive workload, but because of a terrible job fit.

The more proactive you can be about voicing your specific desires for work assignments and career growth opportunities, the better. If you don't, you may risk someone making those important career decisions for you. Gulp!

If you're an organizational leader, take your employees' work assignment requests seriously. Engaged employees who are proactive about their own growth are a gift to organizations! When people feel stagnated, give them room to grow -- preferably in the direction they want to grow.

2. I feel like I have no control over my relationships at work.

A recent Gallup poll of 7,500 American workers found that the causes of burnout have "less to do with expectations for hard work and high performance -- and more to do with how someone is managed." The old saying, "people don't quit jobs, they quit bosses" applies here. Interpersonal issues are underscored when the problem is with a boss instead of a colleague because of the inherent power difference. When people work for an overbearing micromanager or an abusive boss, they often feel powerless to address it because of (justified) fear of making the problem worse, retaliation or even dismissal.

If tense workplace relationships are at the root of your burnout, consider your options for addressing it and choose the one that feels safest (especially if the issue is with your boss). Timing matters, so choose a time to have a discussion when you feel calm, not triggered or in the middle of a blowout.

If you're a leader and an employee reports an interpersonal issue at work (or, heaven forbid, raises an issue with your own behavior), take a deep breath, listen, and don't take it lightly. Unresolved interpersonal dynamics are one of the main reasons organizations lose good people to more civil and supportive workplaces.

Related: Experiencing Burnout? Ask These 3 Questions to Help You Fall Back in Love With Your Business.

3. I feel like I have no control over the future of my career, and it's leading to burnout.

Sometimes people outgrow jobs. And sometimes people outgrow entire industries. I work with many people who feel trapped on a certain career path, especially if they've invested a significant amount of time and energy getting there. I remember feeling that way myself back when I was a professor and believed I had no choice but to stay on that track.

Many people struggle to stay on the career path they're on until they just can't do it anymore -- until they get too miserable or depressed or (you guessed it) burned out. If your burnout is because you're in the wrong profession, may I kindly suggest you work toward making a change? Things aren't likely to get better until you do.

This is a tricky issue for organizational leaders to manage. The best you can do is help people to keep growing within the organization so that they (hopefully) won't feel the need to leave for greener pastures. But if you run a law firm and one of your lawyers wants to become a brewmaster (a real career change one of my clients made), there's not much you can do but wish them well.