You know that old saying that you should not harbor ill feelings? And that it's unhealthy to keep things inside, so you should vent to help you feel better?

Maybe you just need to air things out about a wrongdoing. Your colleagues will be sure to hear you out. No harm done, right?

Not so fast.

According to new research published in the European Journal of Work & Organizational Psychology, while venting and complaining about something or someone may give you that temporary relief, dwelling on its negative energy actually makes you feel worse.

More specifically, if you find yourself engaging in the complaints and criticisms, this mindset will cement that negative event in your head, severely affecting your ability to focus, work and be productive, even a day later.

It Comes Down to "Good Sportsmanship"

Here's what the research found. A group of 112 study participants--all gainfully employed--were tasked with keeping a personal journal of their working week for three days. At the end of each day, participants recorded how much they had engaged in complaining during that day, and how much focus was put on all the things that went wrong at work. They were then asked to rate their mood. Low scores in these areas meant the participant had practiced "good (or high) sportsmanship."

Participants exhibiting low sportsmanship, the ones that focused on the bad experiences for a relatively long time, felt bummed out and in a bad mood up to 24 hours. By stewing about their problems, it would make their bad mood dramatically worse. The next work day, these co-workers experienced lower levels of energy and commitment to their work. Not good for business.

"When sportsmanship was low, worse negative events took a greater toll on participants --they not only reported lower momentary mood and less satisfaction and pride with the work they'd been doing that same day, but they also tended to experience lower mood the next morning," reported Alex Fradera in British Psychological Society (BPS).

"But when sportsmanship was high -- meaning that participants hadn't complained, escalated minor issues, or stewed over things too much -- bad events, even rated as severe, didn't impact mood or work engagement, that day or the next," writes Fradera.

Should Complaining or Venting Stop?

Is the research telling workers of good conscience that they should just zip it and be a good company soldier? Well, not quite.

Holding things back and not letting others know how you actually feel when encountering a stressful work situation is still the antithesis of what should occur.

When bad things happen and problems arise, you need to speak up. But the researchers warn against foot-in-mouth syndrome--rehashing work drama and spouting off emotionally-charged words that will further alienate your colleagues.

The technique is to resolve it tactfully with the right approach, at the right time (a day or two after the negative event, when you're under control and not riled up), and using the right words--think healthy venting--to express yourself in a respectful manner.

What's gotta go? It's that unconstructive criticism and drive-by complaining that we ruminate on for hours that we must consciously choose to avoid. Well, unless you want to ride that 24-hour mood swing to the Land of the Severely Bummed. Who wants to work with that person next to him or her?

By the way, the researchers define good sportsmanship as "tolerating less-than ideal circumstances or minor workplace distractions and discomforts without complaining."

In other words, don't sweat the small stuff. Just get over it and move on.

Bottom line: In the end, it's a choice you make to decide how you're going to feel later. While you may no be able to control everything that happens to you at work, you can control how you react to it.