Many of us ignore our bunged-up nose, banging headache and switch in temperature in order to drag ourselves into the office. However, these are our body’s way of telling us we need to stay in bed. Scientists now believe people’s ‘selfish genes’ are partly to blame for these symptoms, not just the germs and viruses that come with colds and flu.
As the side effects are so miserable, sufferers should keep isolated, which will prevent illness from spreading to others. Therefore, in genetic terms, the symptoms are designed to reduce the infection risk to more people.
“From the point of view of the individual, this behaviour may seem overly altruistic,” says Dr. Keren Shakhar, of the Psychology Department of the College of Management Academic Studies, “but from the perspective of the gene, its odds of being passed down are improved.”
However, in modern times, people often power through, thus spreading illness.
According to Guy Shakhar of the Weizmann Institute’s Immunology Department and Dr Keren Shakhar, feeling ill is an evolutionary adaptation. Details published in the PLOS Biology paper feature a common list of symptoms which support this idea, like loss of appetite preventing disease from spreading into food and water.
Humans aren’t the only species that seek time alone when under the weather; animals behave similarly, suggesting this behaviour has been passed on for thousands of years. It may appear counterproductive, as illness affects chances of survival and reproduction, but it does in fact protect the gene.
“We know that isolation is the most efficient way to stop a transmissible disease from spreading,” Prof. Guy Shakhar adds. “The problem is that today, for example, with flu, many do not realise how deadly it can be. So they go against their natural instincts, take a pill to reduce pain and fever and go to work, where the chance of infecting others is much higher.”
So the next time you wake up sweating and with a pounding headache, let the selfish genes kick in.
“When you feel sick, it’s a sign you need to stay home. Millions of years of evolution are not wrong,” the scientists stressed.