The strain of suppressing negative emotions can have serious repercussions for physical as well as mental health, according to researchers at the University of Jena in Thuringia.
Far from being a myth, a study by Marcus Mund and Kristin Mitte has shown that bottling things up can indeed lead to trouble further down the line.
The body reacts to such repression in a similar way as it does to danger: with a raised pulse and perspiration.
Over time, this can lead to high blood pressure - with a significant knock-on effect on health. The condition is associated with an increased chance of developing a wide range of illnesses, from coronary heart disease to kidney damage.
In the original article published last year in the journal Health Psychologies, the researchers identified a particular group, so-called "repressors", who were particularly at risk.
"These people are distinguished by the way that they attempt to conceal outward signs of fear, and also by their defensive behaviour. They avoid risks and always seek a high level of control over themselves and their surroundings," Marcus Mund explained in a statement on Thursday.
But the news is not all bad for such individuals. Although they might be at a higher risk of developing certain illnesses associated with high blood pressure, other diseases, such as cancer, show no correlation with emotional repression.
And in other respects they tend to fare better than their looser-tongued counterparts. Recovery from a range of conditions appears to be faster among the repressors.
"Because of their great need for control, repressors are generally very disciplined and are more motivated to adapt their lifestyles in line with their condition," said Mund.