glucose, crackling your synapses, and shifting your brain waves, surging your neurotransmitter levels up and down. Long-term, each of these changes leaves a trace. As you feel fear, excitement, desire, delight, and other emotions, blood surges into various regions of the brain, growing new brain cells, bulking up one area, atrophying another. Certain neural paths and connections are dug deeper; others are left to wither and die. Each of these biological shifts may even alter your genetic expression.
These ups and downs are not all bad, though. The enduring legacy of lifetimes of these surges and shifts made it possible for the human race to adapt to a changing environment, and they’re the reason we’ve survived astounding challenges through the millennia. The reason we’re still around is because our ancestors paid more attention to negative stimuli than to positive stimuli, a human trait. Psychologist Roy Baumeister called this our “negativity bias.” 20 We’re the great-great-great (times a thousand) grandchildren of the people who survived vicious attacks and raging storms, because they knew that danger meant they had to react quickly and keep those close to them safe from harm. We can thank our ancestors for being Nervous Nellys—they kept the human race alive, after all—but they also cemented the modern human brain’s innate focus on negativity. Because of the strength of that instinct, unless we today learn to counter that dark focus, we soon discover that negativity can drown out positivity way more easily than the opposite. (Psychologist Paul Rozin quotes an old Russian saying that sums it up well: “A spoonful of tar can spoil a barrel of honey, but a spoonful of honey does nothing for a barrel of tar.” 21 )
Yes, we evolved and survived as a species primarily because we were constantly on the lookout for danger, our brain developing a habit of seeking out and fixating on the negative. And that tendency can get even more pronounced within an individual lifetime. If we experience a trauma, especially in early life, that event gives us irrefutable proof that our innate bias is correct, programs the developing brain to overreact to future stressors, and further strengthens our SNS’s already heightened reactivity. 22 If we don’t do something to change these unconscious instincts, our SNS continues to dominate and we become “wired to worry,” gravitating toward fear-based, hectic, run-run-run lives. The chronic activation of our stress hormones ages our brains, our skin, and our hearts, and we get locked into the downward spiral of Negative Feedback.
Triggering stress can become such a default that our PNS can lose some of its power and become weakened. Luckily, we humans have learned that we can counterbalance this deficit. Hanson says we can consciously work to strengthen the PNS with, for example, deep-breathing techniques, meditation, yoga, and other centering, stress-relieving activities; such “work” helps us relax and allows the body to release tension routinely, before it can build up and become toxic. 23 For example, one Nepali study showed that a type of meditative exercise called pranayama can help strengthen the parasympathetic system in as little as five minutes a session. By slowly breathing in, through both nostrils, for four seconds, and then breathing out for six seconds, while thinking about an open blue sky, study participants significantly reduced their blood pressure and slightly reduced their heart rate. 24 This type of deep breathing exercise has been proven to strengthen the sensitivity of the baroreflex, a mechanism in our cardiovascular system that inhibits the SNS and activates the PNS. When we strengthen the baroreflex, we strengthen the PNS. 25 Neuroscientists, psychologists, meditation teachers, and even trainers for the U.S. military, who seek methods to help manage soldiers’ chronic stress, have found that the stronger the PNS is, the more flexible and responsive
These ups and downs are not all bad, though. The enduring legacy of lifetimes of these surges and shifts made it possible for the human race to adapt to a changing environment, and they’re the reason we’ve survived astounding challenges through the millennia. The reason we’re still around is because our ancestors paid more attention to negative stimuli than to positive stimuli, a human trait. Psychologist Roy Baumeister called this our “negativity bias.” 20 We’re the great-great-great (times a thousand) grandchildren of the people who survived vicious attacks and raging storms, because they knew that danger meant they had to react quickly and keep those close to them safe from harm. We can thank our ancestors for being Nervous Nellys—they kept the human race alive, after all—but they also cemented the modern human brain’s innate focus on negativity. Because of the strength of that instinct, unless we today learn to counter that dark focus, we soon discover that negativity can drown out positivity way more easily than the opposite. (Psychologist Paul Rozin quotes an old Russian saying that sums it up well: “A spoonful of tar can spoil a barrel of honey, but a spoonful of honey does nothing for a barrel of tar.” 21 )
Yes, we evolved and survived as a species primarily because we were constantly on the lookout for danger, our brain developing a habit of seeking out and fixating on the negative. And that tendency can get even more pronounced within an individual lifetime. If we experience a trauma, especially in early life, that event gives us irrefutable proof that our innate bias is correct, programs the developing brain to overreact to future stressors, and further strengthens our SNS’s already heightened reactivity. 22 If we don’t do something to change these unconscious instincts, our SNS continues to dominate and we become “wired to worry,” gravitating toward fear-based, hectic, run-run-run lives. The chronic activation of our stress hormones ages our brains, our skin, and our hearts, and we get locked into the downward spiral of Negative Feedback.
Triggering stress can become such a default that our PNS can lose some of its power and become weakened. Luckily, we humans have learned that we can counterbalance this deficit. Hanson says we can consciously work to strengthen the PNS with, for example, deep-breathing techniques, meditation, yoga, and other centering, stress-relieving activities; such “work” helps us relax and allows the body to release tension routinely, before it can build up and become toxic. 23 For example, one Nepali study showed that a type of meditative exercise called pranayama can help strengthen the parasympathetic system in as little as five minutes a session. By slowly breathing in, through both nostrils, for four seconds, and then breathing out for six seconds, while thinking about an open blue sky, study participants significantly reduced their blood pressure and slightly reduced their heart rate. 24 This type of deep breathing exercise has been proven to strengthen the sensitivity of the baroreflex, a mechanism in our cardiovascular system that inhibits the SNS and activates the PNS. When we strengthen the baroreflex, we strengthen the PNS. 25 Neuroscientists, psychologists, meditation teachers, and even trainers for the U.S. military, who seek methods to help manage soldiers’ chronic stress, have found that the stronger the PNS is, the more flexible and responsive
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