Thermoregulation – a superpower YOU have !

June 2017

How can we run in the heat of L.A., swim across the sea between France and England, or survive accidents in the Rockies? Because we thermoregulate! Behind this somewhat barbaric word lies simply the capacity of our body to constantly adapt to the situation to remain at a stable temperature. The ability to thermoregulate is not just a fancy feature, or a talent that only some of us have at birth. This (super)power is actually life-critical.

Many of our vital organs, such as our brain, heart, and kidneys only work at a temperature approximating 98.6 °F (37 °C). Just a few degrees above or below can cause serious stress on these organs and impair their functioning. Without thermoregulation, one hour of moderate walking at the park would make you so hot that you would fall unconscious. But Human beings can swim in cold seas, cycle the Tour de France in July, and survive accidents in very cold regions. We can go through such extreme situations because our body has several weapons to fight against threatening thermal conditions.

First, let’s mention that we continuously produce heat. You, me, and every living person on Earth and beyond produce heat throughout the day. Even when we sleep our body remains active and this internal activity creates heat. In addition, as soon as we start moving we produce more heat. But to avoid overheating and collapse in the park we must get rid of this extra heat. We need to transfer it to the surroundings. So when it gets hot or when we start exercising, our brain sends a signal to open the blood vessels of our skin, hands, and feet. The result? The amount of blood flowing in our skin increases to reach almost two gallons every minute (8L per min)! A lot of heat is released like this. When this is not enough, we start to sweat… a lot. Walking fast in the heat can make you sweat up to two gallons (8L) over the course of the day! Our skin and t-shirt get wet, and as they dry, they cool, thereby cooling our body. But dripping sweat on the floor cools nothing but the floor!

Just like when it’s hot, the first response of our body to defend against cold is the tuning of the amount of blood flow. It is reduced to a minimum in places where it is not really needed: the extremities. Our hands and feet get cold -and uncomfortable- but as a reward, our body heat is maintained around the vital organs. If the temperature keeps falling, our muscles start to get harder and eventually demonstrate short, uncontrollable contractions. This is shivering. It is very uncomfortable and can reduce our ability to do other things, but at least it produces some heat and helps you stay alive.

But the most efficient weapon against harsh environmental conditions is our behaviour. We seek shade in the heat, look for warmer places when it’s cold, or adjust the number of layers we wear, sometimes without even noticing it! Without behavioural adaptation and the control of our blood flow, we would be continuously switching between sweat and shivers…

Thermoregulation is essential for your survival. It’s also required if you want to perform at your best, enjoy crazy challenges, or simply remain comfortable at work. Now that’s a superpower. The good news is YOU have it!