The first five days of the cold shower challenge has proven to be far easier than I expected.
Now, the first morning was pretty intense. It took around two minutes to catch my breath and each time the water hit the back of my neck, it was like getting electrocuted. As I stood there wondering if I was ever going to get oxygen to my lungs, I was tempted to shut the water off and wash my hair another time.
However, I eventually gained enough control of my breathing to do a quick lather and rinse and called it quits after 3.5 minutes. Toward the end, my legs started to tingle, which I think was partly due to the cold and partly due to my locked out knees and inability to relieve the tension running through my body. I quickly sought refuge underneath my towel, and the wave of energy and panic became manageable.
For whatever reason, this was the only session where things felt unbearable. Each morning since has left me in a state of shock for about 10 or 15 seconds, followed by a boost of energy and mental calm. I won’t go as far as saying I’m comfortable during these showers, but the thought of taking a cold shower doesn’t haunt me either.
Although the initial shock subsides rather quickly, I have experienced an interesting effect after drying off. Once the icy water droplets are wiped away, I can literally feel a sense of warmth rush over me. Out of curiosity, I wanted to find a possible explanation for this sensory overload.
Let’s talk about body temperature.
It is common knowledge that the human body runs an internal temperature around 98.6 degrees Fahrenheit. Assuming someone is in a climate controlled room, with a light layer of clothing, the surface of the skin is around 90-91 degrees. Although I’m sure many of you out there would debate this reality given the consistent freezer like temperatures of your significant others (or yourself).
I mention these facts in order to provide an understanding that water at a lukewarm 60 degrees is actually cold enough to induce hypothermia. In fact, any water below normal body temperature can cause damage.
When I read this, I was really surprised. A sunny, 60-degree day is about as perfect as it gets in my eyes, but transfer that temperature from air to water, and I could find myself in a heap of trouble. According to the Personal Floatation Device Manufacturers Association, the human body cools 25 times faster in cold water than cold air, which is just another reminder that we are very much meant to stay on land (I like to say I have a certain “respect” for water).
Now, I don’t have a thermometer to stick under my shower head to see how cold the water actually is, but from what I’ve read it’s reasonable to suspect a temperature of around 65 degrees. That’s an immediate 25-degree swing from my stable skin temperature, so any feelings of shock shouldn’t be unexpected.
So, what happens inside the human body when met with this sudden change? Well, there are quite a number of things that I will address in future posts, but sticking with the exploration as to why my body is overcome with warmth after drying off, let’s dig into vasoconstriction.
One of the natural physiological responses to an abrupt lowering of one’s body temperature is the narrowing of the blood vessels (a.k.a. vasoconstriction). Just like you have to reprioritize your daily to-do list whenever an emergency comes up, your body reprioritizes keeping your vital organs fully functioning over keeping the feeling in your extremities.
As your blood vessels constrict, the heart has to work harder and harder to keep blood flowing to your extremities, which results in neuron damage (i.e. losing feeling in your fingers and toes) in extreme circumstances. This vasoconstriction allows your vital organs to receive more blood flow than usual in order to fight against the lowering temperatures near the body’s surface.
A great example of how this works was documented by astronaut John Grunsfeld in his first attempt to climb Mount Denali. After eclipsing 10,000 feet, he started to notice his toes were getting really cold (go figure). Once he reached his camp, he took the temperature of his toes and chest, which had a staggering 46-degree difference (42 degrees versus 88 degrees)!
His heart was working hard to keep things like his liver and kidneys working properly without much concern on whether or not a few toes were lost in the process. Our bodies are amazing things, and have an astute understanding of what we do and don’t need in order to stay alive.
Although I’m not experiencing quite this drastic of temperature difference between my outer skin and internal organs, it should come as no surprise that once my body is dried off, the widening of my blood vessels provides a surge of warmth to my skin’s surface. I find it pretty cool to feel my body's need for homeostasis so noticeably.
Science is cool, the human body is amazing, and exploring this topic has proven to be a fruitful endeavor thus far. Next week, I'll be digging even deeper into the science world by highlighting how cold water immersion is being used to slow the progression of a debilitating disease. I hope you’ve enjoyed this journey so far and look forward to seeing you in the comments below!