Mitchell thinks he is making himself look great when he emails his boss at midnight on a Saturday on his BlackBerry.

Eileen thinks she's saving her job by being the last one on the IT team to leave every evening.

Najit thinks she's got the world's best client relationship because she never says no to a request.

Adam burns through double espressos getting his client work done and cuts back the hours he reports so he's not perceived as burning up billable hours.

What's wrong with this picture? Why are we killing ourselves? How are these things really making us look? I'm all for seeing commitment and diligence from my team, but the last thing I want to see is that they are burning themselves out or putting on a performance for my benefit.

As I hear more and more stories of overkill, I think of the concept of Energy Management and how it is increasingly becoming more important in our global work environment.

Energy Management is a phrase that may have originally been coined by Nina Merer, a corporate trainer and coach practicing in the late 1980s and early 1990s. Her Energy Management programs took traditional time management concepts and reframed them as prioritizing energy resources.

Energy Management is an art form. In order to manage energy effectively, we need to make sure we have an equal amount of input to output. When we start depleting our energy stores without recharging them, we sabotage our ability to work effectively.

Why are we convinced that "above and beyond" makes us look more valuable to our company? It's perfectly appropriate to demonstrate our competence or loyalty to our organization, but how do we know when it's overkill? How do we protect our energy from being depleted? The best way to distinguish between appropriate "above and beyond" and overdoing it is to ask yourself these three questions:

• Is what you're doing sustainable over time?

• Is what you're doing something that really adds value?

• If it doesn't add value and if it's not sustainable, are you gaining something important from it?

When you answer yes to any of these questions, above and beyond is the right decision. When you answer no, you have something to think about, and that's setting boundaries. Remember these important boundary-setting rules, and you can avoid sacrificing your precious life energy with no return on the investment.

Your time and energy are valuable.

If you don't protect your valuable energy, who will? Unless you are superhuman, your job probably demands that you set up some rules about jumping to the rescue or going above and beyond the call of duty. Remember that your time and energy are valuable, and that means you must prioritize the time that feeds your energy, not just the time devoted to performing. Customers, bosses, key deliverables—all of these are important. How do you balance everything that comes your way during a given week? By making sure you set clear expectations of what you can and cannot deliver.

A coach on our team recently told me this story: Two principles in a midsized company hired Ken to facilitate a team meeting. They were concerned about holding the meeting in their conference room, which they had just designed and built in their new office space. When asked why they were uncomfortable, they said, "We're always interrupted by emergencies if we're in the conference room instead of a hotel. It makes it impossible to get anything done, because we're stressed out and waiting for the next thing to happen." If they are in the office, they are unable to set a boundary; and if they are out, they are able to set one. It is not as if emergencies will not happen—but if they are at a hotel, they won't know about them.

Their challenge was to set the clear boundary that they couldn't be interrupted during the meeting. That boundary allowed them to use their own facilities for productive work. Once they started valuing their own time, they were able to create a rule that no interruptions were allowed.

Making yourself look good doesn't mean kissing up.

Dr. Wayne Dyer is widely credited with the wise saying, "You teach others how to treat you." Well, I'm a big believer in that statement. You teach others to regard you as important by respecting your own time and energy, not by always asking "How high?" when they say "Jump."

An executive in my coaching practice, "Stan," is a key account director for a global consulting company that works with big-name clients worldwide. His clients are very demanding and will call at all hours of the day or night with requests both large and small. Instead of telling clients that some issues should be dealt with during business hours or with someone else on the team at a different level, Stan's response is to be constantly available and to try hard to meet every possible need at any hour of the day.

Unfortunately, this is not sustainable, nor is it adding any value. Stan's belief system has always been that the customer is always right, and that great customer service means always making yourself available for any issue that might come up. This is an excellent attitude, but what about when that isn't actually serving the client anymore? Stan is so exhausted that his mind isn't clear to address the big picture strategic issues with his client. Stan's challenge is that he has set up a dynamic in which the client expects him to perform above and beyond all the time. He has to set up a new relationship in which he teaches them that he can be the most useful when he protects his time and isn't always available to them for every small thing.

In sum, it doesn't make you look good to be constantly there, constantly say "yes" or constantly focus on one stakeholder above all else—be that your client, your boss or your project.

You have a choice – sustainability or burnout

In order to function at our best, we need to work in a way that doesn't cause burnout or fatigue. Sustainable work practices support our ongoing role and responsibilities over time, not just in the heat of the moment.

I know something's wrong in my world when I'm concerned I can't handle one more question from my team or one more deliverable or I'll be crushed by the weight of my to-do list. This is a signal to me that I need to take a deep breath and set some boundaries around my time and energy.

One of the keys is to take responsibility for our own boundary-setting, and not to blame overwork on bosses, colleagues or the high-pressure systems we work in. Author and corporate stress-reduction expert Doc Childre says, "One of the biggest contributors to low-energy fatigue is blame. Blaming a boss who made you work late or your impossible, overloaded life will only drain you. Fatigue from emotional energy drain results in diminished presence during the workday." We all have our moments of complaining, blaming or frustration, but in the end, we have a choice. We can choose when to go above and beyond, we can choose to set clear boundaries and we can choose to adapt or to leave our jobs altogether if they are not manageable.

Karlin Sloan, M.A., is founder and president of Karlin Sloan & Co. (www.karlinsloan.com), based in New York City and Chicago, which provides executive coaching, team-building and leadership development.