An open mouth can get you in trouble. Serious trouble.

It can even lead to cardiac arrest, especially in cold weather.

One thing we’re having an abundance of this year, you’ve probably noticed, is cold weather. And search as I might, I can’t find any weather channel that holds out much hope for anything to change, except for the worse, for the foreseeable weeks – maybe months.

We’ve all heard of people collapsing, even dying, while shoveling snow. It’s usually put down to the physical exertion – and to an extent, that’s true.

It’s true because during heavy exertion, we usually start heavy mouth breathing, taking in great gulps of air through our mouth. The heavier the exertion, the bigger the gulps. The bigger the gulps, the more cold air intake.

So what’s the problem with that? Sounds perfectly normal.

The problem is cold air. Sudden intake of winter-cold air through the mouth goes directly to our ‘core’ and can shock our lungs. And with snow shoveling, we can soon find ourselves breathing heavily – and usually through the mouth. Studies show this causes CO2 levels to drop which, in turn, reduces blood flow to the heart. Obviously, this is not good. Often, cardiac arrest ensues, also not good.

You wouldn’t think, after the hundreds of thousands of years we’ve been kicking – and shoveling – our way around the world that we’d still have to learn how to breathe?

But, if you go by the plethora of articles and books, from the public and medical research alike, we evidently do.

From books to classes to long, complicated instructions, people are being taught “how to breathe.”

But the basics are super simple: Shut your mouth and breathe through your nose.

Perhaps the two most dangerous mouth breathing times are the aforementioned heavy exercise in cold weather and sleeping with your mouth open – especially if you have sleep apnea, where a person actually stops breathing several times during the night. After a few seconds, they start with a great gulp of air. Sometimes, they don’t ever start breathing again.

Many people have sleep apnea and don’t know it. If you awake with a dry mouth and feeling like you wrung out, chances are, you have sleep apnea. If people tell you you snore a lot, you well might suffer from it. It’s something that needs to be checked.

So just how should we perform the one thing that we have done, second by second, since we squalled our first breath? Through the instrument given us to do it with: the nose.

The nose is uniquely designed to take air safely into our body. It takes fresh air through its chambers, warming and humidifying it on its way and delivering it to our lungs and core safely pre-warmed and moisturized. It also, via the fine hairs in our nostrils, the cilia, filters out germs, dust, etc.

Your nose also produces a small amount of nitric oxide via the sinus mucous membranes. Nitric oxide acts as a bronchodilator and vasodilator. That helps lower your blood pressure while increasing oxygen in the lungs. Nitric oxide also kills viruses, bacteria and other germs. The nose is quite a marvel of design. Its purpose is for breathing – and holding up our glasses.

The mouth is for eating and talking. Otherwise, we should keep it shut.

Marion Tucker-Honeycutt, an award-winning columnist, a Maine native and graduate of Belfast, now lives in Morrill. Her columns appear in this paper every other week.