It's not clear why men may have a weaker immune response to respiratory viruses, but hormones could play a role, with the "female" hormone estrogen, in particular, providing a protective effect against these viruses, Sue said.
The study examined the rate of hospital admission of men with reported flu and women with reported flu, they found evidence that adult men have a higher risk of hospital admission and higher rates of deaths associated with flu compared with women, regardless of underlying disease.
"No scientific review has examined whether the term "man flu" is appropriately defined or just an ingrained pejorative term with no scientific basis", he writes in an article published December 11 in the British Medical Journal.
And then this: "In an unscientific survey, men suffering from a flu reported taking more time off from work than women".
Some evidence also supported a finding that men suffer more from viral respiratory illness than women because their immune systems are less robust.
Lead researcher Dr Kyle Sue from the Memorial University of Newfoundland found fellas have weaker immune systems when it comes to dealing with chest, cold and flu bugs.
"There need to be more studies, higher quality studies that control for other factors between men and women before we can definitely say that this difference in immunity exists", he told the Guardian.
"However there has been some research to suggest Respiratory Tract Infections - as they are known - can present more severely in men than women and the best advice for anyone affected is to rest at home, drink plenty of fluids and to take over-the-counter painkillers, such as paracetamol".
Medical professional also deserve some of the blame, Sue says, since "clinical observers are more ready to...under-rate men's symptoms".
In short, women have stronger physical constitutions than men. For our ancestors, the effects of testosterone (i.e., increased muscle and bone mass) may have outweighed the potential immunosuppressive effect of the hormone, he said.
For all this, Sue sees the term "man flu" in its current context as "potentially unjust".
"I think the symptoms are real", Sue said.
Also, she found that males are more susceptible to complications and exhibit a higher mortality due to many acute respiratory diseases. In times of illness, it allows men to conserve their energy by lying on the couch or not getting out of bed. "Is it that women are more resilient, that they are able to juggle more when they are ill, or is it that they don't have as severe symptoms?" Sue asked. "I was surprised that there were far more female authors for the studies I cited than males".