It's about that time of year when those cold and flu viruses will be making yet another surge across the country. When they hit, we're certain to encounter a number of symptoms including sniffles, coughs, sore throat, and fever. For most of us, this will be just another moment where we've caught a bug. But for some, particularly men, the experience may cause a unique consequence more commonly known as the "man cold."
The condition is difficult to define but anyone who has seen it knows what it entails. Based on a survey in 2010, men tend to complain more about symptoms. They also tend to exaggerate their illnesses. Though this is not universal among the male population, those who fall victim seem to suffer endlessly until they miraculously return to the best of health.
Scientifically speaking, there is some validity to the "man cold." In 2010, a study of gender differences in immune responses suggested men may suffer more from the occasional cold or flu infection. This was later supported in 2013 with a study looking at the immune response to the influenza vaccine. There was indeed a gender gap and men were on the losing end.
As to the reason for the difference, the culprits appear to be sex hormones. In the 2013 study, testosterone suppressed the male immune system making a cold and flu more troublesome. As for the opposite of testosterone, estrogen, in 2014, the chemical was shown to enhance immune activity in the lung and help reduce the severity of infections.
But while the biological mechanism behind the "man cold" may be somewhat understood, there is still one burning question left unanswered: why does it happen? After all, we all encounter a variety of pains, not just colds and flus. There has to be some underlying social health factor hidden within the moans and groans.
There now may be an answer. Last week, two Israeli researchers offered a hypothesis as to why men (and women) experience such a sudden change when infected. The basis for their theory, however, was not to gain attention, but to preserve the species. To them, the real reason behind the aches, pains, and plaints appeared to be a form of altruism to ensure the rest of the population doesn't end up with the pathogen.
The team didn't specifically look at the "man cold" but instead what they called sickness behaviour. The symptoms include pain, fatigue, depression, loss of appetite, and most importantly, a trend towards social isolation. All of these symptoms come from the production of an immune response once an infection begins.
First, the authors attempted to explain the biology behind sickness behaviour. Deep within each of us, our immune cells continue to circulate looking for any signs of an attack. When one happens, a variety of molecules called cytokines are produced. These chemicals circulate through the body and may end up affecting various regions of the brain, including those responsible for social functions, the thalamus, hypothalamus and amygdala. When cytokines meet the brain, changes in emotion, learning, and even altruism can occur. Over a short period of time, an individual can transform from a happy, well-adjusted person, to one looking for isolation.
The duo then moved from the physical to the root of their theory, the social, suggesting the reason for this behaviour change may be a psychological phenomenon known as kin selection. Initially, this concept was used to explain how parents tend to sacrifice themselves for the betterment of their children. But in a larger context, this drive to serve the larger cause may also work to help us reduce the spread of infection. This type of experience has been seen before during the time of the Great Plague when an entire city isolated itself to protect neighbouring towns. For the duo, this drive to protect others may be an underlying reason for sickness.
If the theory is correct, then there are three reasons for sickness behaviour and yes, the "man cold." The first is to reduce the chance of infection to susceptible people. After all, when we are sick, we tend not to trust anyone other than those we find closest to us. The second is to ensure kin selection is maintained. By keeping to ourselves, we are ensuring we don't cause troubles for others. Finally, being sick helps to reduce the potential for an outbreak by limiting the number of possible contacts during illness. This indirectly ensures our population will thrive by reducing the chance of decimation by an infectious disease.
This hypothesis may be sound but the authors also admit modern day influences do tend to go against the intentions of sickness behaviour. In the 2010 survey of the "man cold," almost three-quarters of the men, despite their symptoms, still went into work. In another example, the ability to travel across borders in a matter of hours allowed one man to take Ebola from West Africa to the United States. Both directly contradict the kin selection theory and may require even more investigation to determine whether there is a cutoff point for altruism based on illness.
While the researchers continue to explore and learn more, for the rest of us, we can learn to appreciate and even respect the "man cold." After all, there is a good reason for all those moans, groans, and complaints. He's just trying to help preserve the human race.
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