‘Man flu’ may be real, says review

Tired of his male friends and colleagues complaining of being criticized for not manning up when they feel fluish, Dr. Kyle Sue set out for evidence that “man flu” is legitimate.

According to his review, men aren’t whiners, but rather the immunologically inferior sex, a phenomenon for which there might be evolutionary explanations.

Sue found evidence men tend to have worse symptoms, be hospitalized more, and die more often from influenza than women, regardless of underlying disease.

“The concept of man flu, as commonly defined, is potentially unjust,” Sue, a clinical assistant professor in family medicine at Memorial University of Newfoundland, concludes in the Christmas edition of the British Medical Journal. The annual issue features quirky, peerreviewed scientific papers based on real data.

(“While we welcome lighthearted fare and satire, we do not publish spoofs, hoaxes or fabricated studies,” the prestigious journal assures.)

As Sue reported, the Oxford dictionary defines man flu “as a cold or similar minor ailment as experienced by a man who is regarded as exaggerating the severity of symptoms.”

“Since about half t he world’s population is male, deeming male viral respiratory symptoms as ‘exaggerated’ without rigorous scientific evidence, could have important implications for men, including insufficient provision of care,” Sue wrote.

So, he performed a literature search. First came animal studies showing female mice have stronger immune responses than male. University of Ottawa researchers reported last year that male mice infected with a bacterial infection “displayed more sickness behaviour” and bigger fluctuations in temperature than female mice.

Mice aren’t the perfect stand- ins for humans. However, Sue also found studies suggesting sex differences in human exposure to influenza.

For example, one U. S. study that examined flurelated deaths from 1997 to 2007 found that, for adults, within several age groups, the rate of flu- associated mortality was somewhat higher i n men t han in women, regardless of underlying heart disease, cancer, chronic respiratory disease or kidney disease.

A 2013 study by Stanford University researchers found women tend to have a generally stronger antibody response to flu shots compared to men with high amounts of circulating testosterone (men with relatively low testosterone responded more or less the same as women). That suggests higher levels of testosterone suppress the immune system, while estrogen is immune-enhancing.

Others have found the sex differences appear to disappear when menopause hits and estrogen levels fall.

Some have postulated a robust immune system is less vital for men, from an evolutionary perspective, “because males of many species are more likely to die from trauma before an infection kills them,” Sue said.

The energy needed to clear their bodies of viruses may have been better invested in other “biological processes,” he said, l i ke growth, muscle development and reproduction.

“Evolutionarily we selected more for men with bigger muscles and more physical strength as opposed to a better immune system,” he said. Men also had to compete with other men — the “live hard, die young” strategy — that led to “less investment in immunity.”

“There are benefits to energy conservation when ill,” Sue wrote. “Lying on the couch, not getting out of bed or receiving assistance with activities of daily living could also be evolutionarily behaviours that protect against predators.”

In an interview, Sue said he gets why women might complain when men don’t look as sick as they say they feel.

“Is there a physiological basis for that, or is it just that women are more resilient and able to juggle more things than men can,” he said. Though it’s changing, women generally shoulder more domestic duties. “Women are feeling that, ‘ we have to deal with all of this, why can’t men just be like us and manage more while they’re sick?’”

“I t ’s not s ayi ng t hat women don’t need to rest as well and be taken care of when they’re ill,” he said. “Both genders could probably benefit from that.”