This week, Aussie audiences watched on as acclaimed TV host Todd Sampson entered a cage fighting ring to face one of his greatest fears: surviving a round in a professional Mixed Martial Arts bout.
In his new science documentary 'Body Hack' -- that premiered on Channel Ten earlier this week -- Sampson has stepped out of his comfort zone to explore how human beings adapt to extreme physical challenges. Instead of observing them, he is becoming them.
Controlling your breathing is probably the most important thing you are going to learn. Mike Winkeljohn
Which brings us back to going up against a professional cage fighter -- and embracing fear.
'Before I teach you how to strike and throw punches, I want to first find out how well you can take punches," his trainer Mike Winkeljohn from Albuquerque, New Mexico, said.
Standing eye-to-eye with middleweight fighter Phil Hawes for the first time, Sampson buckled and bolted.
The fight or flight response
It is an automatic stress response that we have been endowed with to facilitate survival.
"If we consider ancient times, the natural environment would have been replete with life-threatening animals all seeking to ensure their offspring's survival," Dr Muireann Irish, Senior Research Officer at Neuroscience Research Australia, told the Huffington Post Australia.
Imagine you find yourself eye-to-eye with a sabre-toothed tiger. The sight would trigger an automatic response to allow you to run faster, jump higher or see more clearly to escape unscathed.
"In this way, being able to perceive a stimulus as threatening and to respond swiftly has been critical in ensuring the survival of humankind," she said.
Today, the story is a little different.
"While we no longer have to run from tigers or woolly mammoths in the wild, fear and anxiety are unfortunately very much present in our lives."
"We now contend with psychological triggers such as deadlines, presentations, performance reviews, that while not truly life-threatening, nevertheless trigger off the flight or fight response."
What happens when we face fear?
A complex biochemical process is triggered when we perceive a situation as threatening.
Dr Irish explains:
"A structure located deep in the brain called the hypothalamus sends something akin to a 'distress signal' to the autonomic nervous system and provides the catalyst to a cascade of physiological events," she said.
If our nervous response starts in the brain, we also have the ability to stop it there.Todd Sampson
Our heart rate and blood pressure increases -- as does our blood glucose levels. Our pupils dilate, our muscles tense and our blood vessels constrict to direct more blood to the major muscle groups.
Our digestion and our immune system are also suppressed to conserve energy for those vital functions.
"Collectively these physiological processes ensure that we can run faster, jump higher and see more accurately, all in the service of escaping the immediate threat," she said.
Meanwhile, our brain becomes more alert and attuned to external surroundings, redirecting "attentional resources to the 'big picture' to ensure that the individual focuses on the main threat".
This is a complex picture to wrap your head around. But managing fear and pain can seemingly be quite simple.
The power of the breath
For his next training session, Sampson and his trainer venture to the 'Hill Of Tears' amidst the mountains of Albuqerque to understand a fighter's emotional regulation.
The key? Slowing down their breath.
"Controlling your breathing is probably the most important thing you are going to learn," trainer Winklejohn said. "Our motto is to get comfortable being uncomfortable."
Breath is the bridge to our nervous system, so if you want to trick your body into believing everything is okay, slow down your breath.Todd Sampson
Why is this the case?
"A common feature of anxiety is rapid and shallow breathing from the upper lungs that can lead to increased shortness of breath. This reflects the activation of the sympathetic branch of the autonomic nervous system in response to a perceived threat," Dr Irish said.
Slow breathing counteracts this stress response by activating the "parasympathetic system", otherwise known as the "rest and digest" system. By signalling the hypothalamus in our brain to regulate our neurohormones, our blood pressure decreases and our heart rate slows.
"Learning to breathe more slowly and more deeply -- from the diaphragm and not the chest -- can counter the effects of the fight or flight response and enable the individual to master their feelings of anxiety."
Whilst you may not find yourself facing a cage fighter any time soon, the message remains clear: master your breath.
Click below to follow HuffPost Australia on Snapchat!