37 °C or you'll die...
Well, you have a little more room to operate than that. But the stakes are clear.
Human beings are warm-blooded animals. That means our body temperature has to stay within a range of around 36.5–37.5 °C (97.7–99.5 °F).
To stay within this range, our body regulates temperature. Much like a thermostat in a house.
Knowing how your body does that will help you dress for hunting.
In most cases, it's about being comfortable, focussed and performing your best. In a few serious situations, it's about survival.
In essence, you need to know two systems. Reaction to cold and reaction to warm.
How your body reacts to getting cold
When your brain senses temperature dropping, it will react in three steps.
- Change behaviour
- Reduce blood flow
As much as we want to think we're thinking individuals, our body controls a lot of our behaviour. The first reaction to cold is for the brain to start activities that will get you out of the cold or raise your temperature. That means getting out of the wind, into the warm etc. Or moving around to start burning calories. After that, your body will reduce blood flow to your arms and legs. It does that to prevent your organs from being cooled by the cold blood.
And that's a critical piece of information for hunters.
Reduced blood flow will reduce your ability to perform "fine motor tasks". That's another way of saying that it will become more difficult to operate your rifle.
The last reaction in this sequence is shivering. Because shivering generates enough movement to burn calories enough to heat you. Beyond that, it goes downhill towards cold shock (hypothermia) and death, but that's a topic for another article.
How your body reacts to getting hot
In the opposite case, when your body senes a temperature rise, the three steps are:
- Changing behaviour
- Increase blood flow
Changing behaviour means getting out of the sun, drinking water, slowing down etc. Increased blood flow will help move heat from your core out to your arms and legs, where it can be cooled down. The last step in this sequence is sweating. We'll cover that in more detail when talking about the ways we lose and gain heat.
It's intuitive to most people that we sweat when exercising hard. Even in cold weather. In cold weather, sweat can become a problem. This is a point we must reflect on when selecting clothes for hunting.
Beyond sweating, we're moving towards heat shock. But as per above, that's a matter for another article.
SummaryThe key points you need to remember from this article are:
- Your body temperature must stay stable around 36.5–37.5 °C (97.7–99.5 °F)
- Your body constantly regulates temperature with two different sets of reactions
- These reactions may also work against you
- They can make it difficult to operate your rifle or end up making you too cold
- So, you need to understand how to manage them
This was a summary of how your body regulates temperature when it gets too cold or too warm.
The next step is to look at the forces that will make you colder or warmer.
That way, you will know the requirements for your clothing system. The role each piece needs to play.
And you can pick the pieces with the right properties, to match a given situation.
That will help you stay safe and efficient. And 100% focussed on hunting.
Sources and recommended reading
- Hypothermia, Frostbite and other cold injuries - prevention, survival, rescue and treatment (G. Giesbrecht, J. Wilkerson) ISBN 0-89886-892-0
- Waterproof and Water Repellent Textiles and Clothing (editor J. Williams) ISBN 978-0-08-101212-3