A study found work stress increased the likelihood of men - but not women - complaining of sore throats and sniffles.
One explanation given for the finding was that men tended to "overrate" the severity of cold and flu symptoms. Women, on the other hand, were more likely to adopt a "stoical" attitude and soldier on in silence.
The South Korean researchers wrote in the journal Occupational Medicine: "Any association between work-related stress and the common cold may be accentuated in males by their reaction to experiencing a cold and attenuated in females by their more stoical response."
"Man flu" is defined by the Wiktionary online dictionary as "a cold or similar ailment as suffered by a male seen as wildly exaggerating the severity of his symptoms".
The scientists studied 1,200 manual workers from 40 different companies in Incheon, South Korea.
They found that men with demanding jobs were 74 among men with "insufficient job control" and by 40% among those with "inadequate social support".
However the researchers could find no significant association between stress factors and cold complaints among women.
In the UK, stress and depression are the biggest long-term cause of work absenteeism, affecting a quarter of all employees.