Much has been said about the so-called "man flu"—when men appear to experience respiratory viruses more severely than women—and lighthearted new research review in the BMJ Christmas issue suggests the phenomenon might exist outside internet memes.
An impetus for research
While the term "man flu" may not exist in medical literature, it's in the Oxford and Cambridge dictionaries. The Oxford dictionary, for instance, defines it as "a cold or similar minor ailment as experienced by a man who is regarded as exaggerating the severity of the symptoms."
But a new research review suggests that it might not all be exaggeration, The Guardian reports. Tired of allegations of symptom exaggeration, Kyle Sue of Memorial University in Newfoundland took a tongue-in-cheek look at existing studies to determine "whether men really experience worse symptoms and whether this could have any evolutionary basis," according to the review.
What the research shows
Relying on evolutionary theory, epidemiology, and studies focused on immunology and endocrinology, Sue in the review wrote that the evidence suggests men might not be exaggerating their symptoms but rather have weaker immune responses to respiratory viruses.
For instance, research on mice suggests that testosterone could lower immune response to influenza while female sex hormones could amplify it. And according to the review, research also indicates that women might get better defense from the flu vaccine: Studies from vaccine questionnaires suggest that women are more responsive to it that men, and research shows "more down regulation of antibody response to vaccination" in men with higher testosterone levels—a finding that indicates testosterone may have an immunosuppressive role.
Further, research shows differences in responses to cold viruses between cells in pre-menopausal women and cells in similar-age men, the research review found. There wasn't a difference between post-menopausal women and similarly aged men.
The research also suggests that men take more time to recover from the flu, citing what Sue called "an unscientific survey" that found women took an average of 1.5 days for recovery while men took an average of three.
And ultimately, the research suggests that flu-stricken men are more likely to be hospitalized and even die when compared with women, Sue wrote. He cited epidemiological data from Hong Kong that show adult men were more likely than women to be admitted to the hospital for flu between 2004 and 2010, as well as observational data from the United States show that influenza-related death rates were higher among men than women of the same age between 1997 and 2007.
However, Sue noted that the studies in his review did not account for other behavior differences that correlate with sex. For instance, men are more likely than women to smoke and less likely to seek preventive care or care when sick.
Writing for Health News Review, Alan Cassels notes that the piece is part of BMJ's traditionally lighthearted Christmas issue, and he critiques some media outlets for not being more critical of the article's research methods. Cassels writes, "A careful look at the methods suggests that this was just one man dredging the literature for studies that would support his hypothesis. It's fine to have an opinion and to marshal an argument in support of it, but let’s not pretend that such selective cherry-picking amounts to a 'study' or 'rigorous' science."
The evolutionary argument
And while Sue acknowledged that the "evolutionary basis" for the man flu "remains unclear," he pointed to other researchers who have suggested that "the male strategy of 'live hard, die young' arising from stronger intra-sexual competition than among females has led to less investment in immunity.'"
In fact, Sue suggested, tongue-in-cheek, that women may only have themselves to blame for the "man flu." By selecting bigger, stronger, and faster men as sexual partners—men who had to focus on fighting and establishing dominance, rather than weaker men who might have had a stronger immune system—women might have helped weed out a more robust immune system among men.
Further, a man's retreat to the nearest couch upon being stricken with the "man flu" could itself be an evolutionary response, Sue wrote. "Classic modes of energy conservation may include lying on the couch, not getting out of bed, or receiving assistance with basic activities of daily living, which could all be effective for avoiding predators," Sue wrote.
The final word?
Based on the research, Sue asserted, "The concept of man flu, as commonly defined, is potentially unjust," particularly given that "clinical observers are more ready to … under-rate men's symptoms."
And while acknowledging the need for further research, he said the evidence as it stands supports a new public health policy: "Perhaps now is the time for male friendly spaces, equipped with enormous televisions and reclining chairs, to be set up where men can recover from the debilitating effects of man flu in safety and comfort" (Healy, "Science Now," Los Angeles Times, 12/12; Zillman, Fortune, 12/12; The Week, 12/12; Davis, The Guardian, 12/12; Sue, BMJ, 12/11; Cassels, Health News Review, 11/13).
This holiday season: How to avoid the flu when you fly
Download this infographic to learn about both the obvious and less obvious locations where germs on planes are rampant.