Having spend the last couple of days largely incapacitated on the couch by a simple common rhinovirus (which may have affected the quality of my last two posts), I've been wondering about the phenomenon of the man-cold, which seems to be more than just an advertising trope. The evidence I have is anecdotal, but it does seem like colds hit men harder than they hit women, and I've been wondering why this would be the case.
The first thing that occurred to me was that women probably do have somewhat more robust immune systems than men, and that makes a certain amount of evolutionary sense on several levels, mostly having to do with reproduction and child-rearing. Also, let's face it, men are a bit more expendable than women in the gene-propagating game; biologically, dad can check out right after conception and baby can survive and even prosper, while mom needs to stick around for a couple of years after that at least for a decent chance at grandchildren.
But I don't think that really answers the question. I don't think the symptoms I suffer when I have a cold are really all that much worse than those affecting my wife when she gets it. No, I think it really does come down to men being wimps, at least with respect to things like colds. And I think there's actually a plausible evolutionary reason for that.
Here's what I mean, first of all, by "wimp": someone with a low tolerance for discomfort. I don't mean pain threshhold, although that's a related concept, because men pride themselves in their ability to press on despite terribly painful injuries. Not that women can't also do this, but rather that we don't see the same kind of gender-linked phenomenon as we do with the man-cold. We don't have "man-sprains" or "man-sunburns". What I'm talking about, at least in the context of men-with-cold-being-wimps, is the kind of discomfort that is not a result of physical trauma gloriously won in battle, but of feeling sick from disease or poison. And I'm suggesting that a low tolerance for that kind of suffering, a propensity to lie in bed and moan from a relatively small degree of discomfort, might actually have served an evolutionary purpose.
Consider our ancestral environment, and in particular the different social/economic roles filled in hunter/gatherer societies. By and large, hunting (and warfare) have historically and prehistorically been primarily male areas, while gathering has been more open to both genders (if perhaps tending to be dominated by females). Hunting and fighting are kind of a high-performance activities, with rather high stakes for failure. If you go to gather roots and berries with a head cold, well, you may come back with fewer roots and berries than if you were in peak health, but the risks of not coming back at all are not substantially higher; it's still worth it to go ahead and collect food. However, going off to raid another tribe's village, or trying to bring down a giraffe or mammoth, a head cold can put you at substantially greater risk of failure and possibly death. In other words, having a cold can make the odds of a successful hunt so low as to be not worth the trouble.
Now, nature doesn't generally rely on our cool rational intellect to make these calculations for us. It doesn't lead us to carefully assess how many calories we've consumed recently, and decide how much more we should or shouldn't eat. Rather, it equips us with animal appetites and instincts; we eat because we FEEL hungry, not because we've made a rational calculation that we ought to do so. Likewise, rather than trusting our ancestors to coolly assess the odds of an ill-timed sneeze spoiling an ambush, nature has given us threshholds for various forms of discomfort that make us feel more or less horrible, and more or less enthusiastic about going out and hunting or gathering or whatever it is we normally do.
And that, I think, is why men are such wimps when it comes to colds. In our ancestral environment, the better decision when you had a cold was not to go hunting, so men are laid low by relatively mild illness, while women will still go out gathering while suffering the very same symptoms. Of course, men aren't wimps in battle, and can ignore pain and fight on despite grievous injuries. But there, the evolutionary payoff is different; it's too late to stay home once you're fighting an angry auroch, so your best chance is to go all-out physically and either kill it or run like hell.