You’re walking on Centennial Trail along West Saanich Road when suddenly a large, tawny animal leaps out of the bushes at you.
The movement triggers your brain’s most ancient emotion-and-alarm system, deep in the most primitive part of your brain. Your amygdala, or fright centre, buzzes the nearby fear-processing centre in your hypothalamus, which instant-messages the alarm to your adrenal glands atop your kidneys, telling the glands to pump out stimulating epinephrine.
Almost simultaneously, your heart starts pounding, your muscles clench, your breath speeds up, you yell, you leap, pivot and crouch to face the animal with your arms raised defensively.
But, wait just a microsecond — your hypothalamus hasn’t finished with you. As you confront the threat, the hypothalamus recruits its nearby buddy, the pituitary gland, and goads it into sending its own alarm signal to the adrenal glands. This time, cortisol floods out, elevating blood-sugar levels and giving you energy to fight or flee — to save your skin.
And then — finally! — your prefrontal cortex kicks in. It analyzes the visual data, it riffles through your memory index and identifies the beast. The cougar about to sink its teeth into your neck … it’s a friendly house cat intent on winding its body around and between your tensed ankles.
Our stress response developed long before humans existed. Its control centre forms the ancient limbic system, deep within what is called the reptilian brain even in non-reptiles. The senses signal possible threat stimuli directly to this area of the brain, bypassing the more recently evolved prefrontal cortex with its higher-level reasoning and decision-making functions.
Which is why, when we are surprised or suddenly feel threatened, the fright–fight–flight response comes near-instantaneously and overwhelmingly, with more reasoned responses lagging.
The limbic system has kept us alive over thousands of generations, when the animals leaping from bushes did indeed mean to munch on us for lunch. It keeps us alive today when that bozo on his cellphone runs the red light and we have to jump out of the way, or when we have to gather the kids and leap out of a burning building.
However, few threats mean life or death to people living in our part of the world these days. But our limbic systems don’t differentiate. They either perceive threat, or they rest quietly.
Any threat will do — the looming deadline, the bit of lip from your teenage daughter, your boss having a bad day and experiencing her own stress responses. It could be traffic jams, public speaking, awkward family gatherings, difficult conversations.
The problem is, while the quick burst of our innate stress response kept our ancestors alive on the savannah and serves us on occasion today, modern stressors just don’t end. That means the stress switch is chronically on, and we are constantly barraged with stress hormones that ramp up our heart and our breathing rates, our blood pressure, our blood-glucose levels and so on.
Chronic stress can kill us. It has been shown to lead to cardiovascular problems, memory loss, inability to learn new information or skills, poor judgment, depression, anxiety, possibly Alzheimers’ disease and even cancer, among other effects.
And it isn’t getting any easier. We’re under more pressure to work 24/7, to multitask, to always be available and instantly responsive no matter what the hour, when what we need most amid the mayhem are regular, frequent, predictable periods of complete downtime, when we can turn off the stimuli and reset our limbic systems to healthy baselines.
Some professionals recommend meditation or deep, yogic breathing — shown to benefit behaviourally challenged high school students in Los Angeles. Others prescribe sufficient sleep, healthful meals and regular exercise. Some suggest reframing stressful situations — by volunteering to help those who are less fortunate, focusing on positive life events and aspects, and nurturing friendships and family.
Others say getting out into nature is crucial — recommending regular hikes and walks in places like Beacon Hill Park or Centennial Trail.
Just watch out for cougars and other predators.
And oversized, overly friendly house cats.