Handshakes lasting longer than three seconds may trigger anxiety, according to one study.
The Dundee University School of Social Sciences study found that meetings and business relationships could also be negatively affected.
In the study, 36 people were interviewed by a researcher about their career prospects before being introduced to a second researcher.
The second researcher would shake his hand for less than three seconds – described as the normal period of time; for more than three seconds or not.
Their reactions were then analyzed.
After a longer handshake, participants showed less interactional pleasure, laughed less, and reported increased anxiety.
After the shorter handshake, they didn't smile that much but said the handshake seemed more natural.
No changes were observed after non-handshake.
Dr Emese Nagy, a psychology reader who led the study, said: "While shaking hands longer may seem like a warm gesture on the surface, we found that they negatively affected receiver behavior even after shaking hands. .
"Politicians are particularly interested in prolonged handshakes, which are often an expression of warmth, but also as a means of demonstrating authority.
"However, our findings suggest that while this may seem impressive to cameras, this behavior may compromise the quality of their personal and work relationships from the start, which could have repercussions for millions of people."
The findings are published in the journal Perceptual And Motor Skills.