Our grandmothers were right about most things, but one thing they, and we, often get wrong is the connection between the weather and getting sick.
The mistake actually makes sense. After all, everyone knows all of our kids, and all of us, get more sick and sick more often in the winter than the summer. And we all also know that it is colder in the winter than the summer. Therefore, doesn’t that prove that cold air causes colds?
After all, why else do they call these miserable illnesses “colds” anyway?
It turns out the answer comes from our friends in Hawaii, Israel, and Indonesia. Even where it is hot as can be, people still get tons of colds. I actually wonder if the runny nose, fever, achy, misery we call a cold is called a cold in India where people get plenty of these illnesses, but usually while is hot outside?
So why are we so sure getting chilled gives you a cold?
Three reasons come to mind:
- As noted, we all tend to get colds in Ohio when it is truly cold, even frigid outside. If we only get sick when it’s cold, it must be the cold that makes us sick, right?
- When we play or work outside when it’s 10 degrees, our nose gets chilled and to protect the delicate innards of our nostrils, our bodies make extra mucus to prevent freezing. So whenever we breathe freezing air for awhile we get a runny nose. If every time our nose gets chilly we get a runny nose, then the runny nose of a cold must be from the cold air, right?
- It’s called a cold! Why would eons of people call the illness a cold if it had nothing to do with being cold, right?
The answer to all three is not right. Here’s why:
Every single cold every caught is caused by a virus. Not cold air, a virus. No virus, no cold, even if it is -20 degrees and you have to stand outside for 6 hours with your feet in ice water. No virus, no cold.
Even more so, if you get a virus and it gets in you and multiplies, you are going to get sick, even if it sunny, 80 degrees, and you are cozy and warm. Viruses cause colds, not the weather. No virus, no cold. Yes virus, yes cold.
Now, one of the most peculiar facts about our relation to viruses, and I mean very peculiar, is their seasonality. Not weather seasonality, but calendar seasonality. No matter what the weather is, setting records for heat and drought, or for cold and wet, most viruses arrive on a certain day each year, and leave on a certain day.
We are nearing one of these great mysteries of biology, right now. The species of virus called influenza mysteriously appears every December and just as oddly nearly completely disappears every April, around the world.
When we look at graphs which plot outbreaks of influenza week over week every year, a pattern emerges. Every line goes up suddenly, and back down just as swiftly. That means that magically the virus appears each year across the United States, and then, just as strangely, it disappears. The climb begins late in the calendar year, and tapers in early Spring. Every year.
This happens everywhere. The influenza virus comes and goes in that same pattern, and on those same predictable dates, in Hawaii, Israel, and Indonesia, where it is warmer. No matter that the sun is beaming, there is no snow, it isn’t dark, people there get colds and flus seasonally too.
So, let’s take a look at our three reasons and see how they stand up to the actual facts:
- We get a lot sicker when it’s cold. That is a coincidence. The cold and flu viruses flare in December around the world. It just happens to be cold in most of the United States. But it would happen even it if was warmer in December. Cold temperatures do not cause colds, only viruses do.
- We get runny noses when we go outside. That does happen, but that’s not a cold, it’s just a sniffy nose until our nose warms up. Cold temperatures do not cause colds, only viruses do.
- We call it a cold. Well, that reflects our confusion, not an actual explanation. Cold temperatures do not cause colds, only viruses do.
Put it all together, and cold temperatures turn out to be associated with colds, they do not cause colds.
Associations are when two events coincide in time or place.
Causes are when one event precipitates another event. If the first event is absent, the other event will not, or will be less likely to, occur.
We know polio viruses are the only cause of polio, because when we got rid of the polio virus, all polio ceased entirely.
We know cold temperatures are associated, in Ohio, with colds, but do not cause them, because when we get rid of cold temperatures in hot areas of the world, people still get just as many colds.
Yes, they are called colds, and they happen in the cold winter, but only viruses cause colds. Enjoy the great outdoors and the biting chills of winter, they will not make you sick.
Enjoy the Season, and To Your Health,
Dr. Arthur Lavin