Sometimes I find myself feeling that my body is less than impressive — especially after a workout, when I can feel my muscles trembling and my lungs straining, and I’m convinced that, if the zombie apocalypse ever did happen, I would probably just let my self get bitten, rather than attempt to spend the rest of my life running away. Dystopian futures aside, however, it’s good to remind ourselves once in a while that our bodies are actually fantastically complex, powerful machines that are extremely skilled at multitasking, regulating themselves, and, oh yeah, keeping us alive.
The human body is delicate in many ways, relying on a finely calibrated balance of chemicals, temperature, fuel, sleep, and exercise, but it’s also tenacious as hell, and has a number of frankly insane mechanisms in place to make survival possible even in the most extreme situations. Not everyone has the same reactions to stimuli, of course — so the fact that, for example, one person could survive with out food for two months doesn’t mean that you or I can — but that fact that anyone could is pretty amazing in itself, and testament to the fact that the body is both awesome and a little crazy.
1. Go without food for up to two months.
The human body can survive on only water for up to 60 days. In 2012, rescuers in Sweden found a man trapped in a car beneath snow who claimed he had been surviving on nothing more than snow for two months; in 2011, a woman lost in Nevada survived for almost 50 days on nothing more than water and a bit of trail mix. Considering that many of us start getting hangry within only a few hours of eating, surviving these extended periods without food may seem impossible, but the body is set up to cope with starvation in a strategic way, first burning through glucose (our main source of energy when food is readily available), then fatty acids converted to ketone bodies. Eventually, the body will start consuming its own muscles to provide energy to the brain.
2. Develop super strength in times of extreme stress. (Well, maybe.)
We’ve all heard stories of mothers suddenly developing the strength to lift cars when a child is stuck beneath; in a 2013 example, two teen girls in Oregon reportedly lifted a 3,000 pound tractor that had fallen on top of their father. This phenomenon, called “hysterical strength,” is not well understood (After all, how would one test it in a controlled environment?), and scientists contest whether it’s actually possible. Researchers have theorized that if it is possible, we have adrenaline to thank. According to Discovery Health, adrenaline and noradrenaline are hormones that help regulate “heart rate, increase respiration, dilate the pupils, slow down digestion and … allow muscles to contract.” In short, they help to ready the body for emergency situations, and enact “flight or fight” responses. Pscyhology Today explains,
When adrenaline is pumped into our circulation, blood is shunted away from our guts (who needs to digest food during a fearful situation, anyway?) and to our muscles. This, in turn, means more oxygen gets to our muscles. Adrenaline also facilitates the conversion of our body's stored energy source, glycogen, to fuel in the form of glucose. The combination of increased oxygen and energy levels strengthens our muscles beyond normal levels.
3. Regulate body temperature.
Extreme heat and cold can be very dangerous for the human body, and we have a number of mechanisms in place to maintain proper body temperature, including sweating and shivering. However, a 2013 study suggests that, at least to some extent, our minds can affect our body temperatures. The study, led by Dr. Maria Kozhevnikov, found that, through certain types of meditation, nuns in Tibet were able to increase they core body temperatures and dry wet sheets wrapped around them with their body heat. When the researchers had non-experts use similar meditation techniques, they were also able to alter their core temperatures. Although these results don’t indicate that we all have a magical ability to warm our bodies in extreme cold, they do suggest that humans have more mental control over core body temperatures than previously thought.
4. Be temporarily immune to pain.
I always want to cry foul during action movies when a character experiences intense physical trauma and then just walks away from it like nothing’s happened. It turns out, however, that people do experience pain differently in emergency situations. In an emergency, the body is flooded with endorphins, which block pain signals. Thus someone may be seriously injured and not be aware of it at first because endorphins are blocking their perception of pain; this is a survival mechanism that allows the injured person to continue to function long enough to get out of harm’s way.