The study results could make employers rethink 'service with a smile' policies.

Forcing yourself to smile at work may lead to heavier drinking once you clock out for the day, according to new research.

A team of researchers at Penn State and the University of Buffalo studied the drinking habits of people who routinely work with the public. They found a link between those employees who regularly fake positive emotions, or suppress negative feelings, and heavier drinking after work.

Penn State psychology professor Alicia Grandey said the results suggest employers may need to rethink any "service with a smile" policies.

"Faking and suppressing emotions with customers was related to drinking beyond the stress of the job or feeling negatively," Grandey said. "It wasn't just feeling badly that makes them reach for a drink. Instead, the more they have to control negative emotions at work, the less they are able to control their alcohol intake after work."

The researchers used data from phone interviews with more than 1,500 workers in the U.S. and it included information about drinking habits and how often they faked or suppressed emotions, also known as "surface acting."

Researchers found that employees who interacted with the public generally drank more after work than those who didn't. The link between drinking after work and surface acting was stronger for those who feel like they lack control over how they can act at work.

"If you're impulsive or constantly told how to do your job, it may be harder to rein in your emotions all day, and when you get home, you don't have that self-control to stop after one drink," Grandey said.

In particular, researchers found employees with one-time encounters with customers, such as a call center or coffee shop, were more likely to drink after surface acting compared to employees in a field like health care or education.

According to Grandey, the study results suggested surface acting is less likely to lead to problems when the employee feels like their work is personally rewarding.