(Newsroom America) -- If you show up at work tired, you may want to focus strictly on your own tasks. New research suggests helping coworkers in the morning can lead to mental exhaustion and self-serving behavior in the afternoon that ultimately can create a toxic work environment.
The study builds on the previous work of Michigan State University's Russell Johnson and colleagues that found helping others at work can be mentally fatiguing for employees.
Turns out, that helping behavior can be particularly harmful when it's done in the morning hours.
"The increase in mental fatigue from helping coworkers in the morning led employees to reduce their helping behaviors in the afternoon and, perhaps more interestingly, they engaged in more self-serving political behaviors in the afternoon as well," said Johnson, associate professor of management in MSU's Broad College of Business.
"They switched from being other-oriented in the morning to being selfish in the afternoon."
Johnson and colleagues studied 91 full-time employees over 10 consecutive workdays (participants completed two surveys a day - morning and afternoon - on their workplace experiences).
While previous research has noted the "dark side" of helping others on an individual's well-being and performance implications, Johnson said, this study is the first to explore the downstream effect on political behavior.
Helping others may not only harm the well-being of the individual, but through the subsequent increase in political behavior may harm others in the office as well, the study says.
"Although we did not identify the consequences of these political behaviors, research has established that political acts from employees can culminate into a toxic work environment with negative well-being and performance consequences."
The authors aren't suggesting workers never help their colleagues in the morning, of course, but that they show discretion, particularly when they start the day already tired or mentally fatigued. When they do help coworkers in such circumstances, employers can make sure they get work breaks and lunch periods to help them recover.
If breaks aren't possible, managers should make sure they encourage proper separation from work once employees return home.