When working with the public, whether as a cashier, receptionist or even a fast-food store worker, you’ve most likely had to fake a smile at least for a few minutes— possibly tons of times.

Though it’s a polite gesture and it’s good for customers and business, it might lead to something a bit dangerous in your personal life.

According to a recent study by researchers at Penn State and the University of Buffalo, forcing a smile at work could lead to heavy drinking.

In the study, researchers interviewed around 1,500 people who routinely work with the public, including nurses, teachers and service industry workers.

The results of the study showed that those who find themselves regularly faking or amplifying positive emotions, like smiling, are likely to engage in heavier drinking after work.

So, if you often fake emotions or try to be positive when you’re actually not feeling it, you might be a much heavier drinker than those who don’t sugarcoat things.

Those who suppress negative emotions are also more likely to drink heavily after work.

While previous study has linked service workers with problematic drinking, Alicia Grandey, professor of psychology at Penn State, said it’s not clear why.

Grandey said:

“Faking and suppressing emotions with customers was related to drinking beyond the stress of the job or feeling negatively. 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.”

Grandey added that she believed employees who fake or suppress emotions may use more self-control in the workplace, but not have a lot of self-control after work.

Grandey noted:

“The relationship between surface acting and drinking after work was stronger for people who are impulsive or who lack personal control over behavior 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.”

She also said that people who work in more rewarding jobs will be less likely to drink afterward:

“Nurses, for example, may amplify or fake their emotions for clear reasons. They’re trying to comfort a patient or build a strong relationship.”

“But someone who is faking emotions for a customer they may never see again, that may not be as rewarding, and may ultimately be more draining or demanding.”

Grandey now hopes this study will change how employers treat their workers.

She said:

“Employers may want to consider allowing employees to have a little more autonomy at work, like they have some kind of choice on the job.”

“And when the emotional effort is clearly linked to financial or relational rewards, the effects aren’t so bad.”