May 2022

Stress, biology and belief

4 min read

“Stress is harmful — learn how to manage it.” This is a common message many of us have become accustomed to hearing. But, like many other statements, it is only half the story and does not paint the full picture. Let’s start with the basics first: the biological mechanisms involved in stress.

We are all familiar with the feeling of stress, but are we familiar with its biology?

Sympathetic ganglia are a chain of neurons that run along our spinal cord, from our neck to below our navel. Their role is to deliver information to the body about stress via acetylcholine. In the brain, acetylcholine is involved in focus and muscles are involved in contraction. When something stresses you, the sympathetic ganglia release acetylcholine. Another group of neurons called postganglionic neurons respond to acetylcholine by releasing adrenaline responsible for the fight-or-flight response. Parts of our body that need to be active have beta receptors that respond to adrenaline and signal blood vessels to dilate (blood rushes into our legs, heart rate speeds up). Other parts that can spare energy have alpha receptors that signal blood vessels to contract. These are parts involved in digestion, reproduction and other “things that are luxuries for when things are moving slow” (Link).

Uncertainty — the body doesn’t label short-term stress

The stress response is the same regardless of whether we face a threat or an exciting challenge. Acetylcholine and adrenaline are the molecular response to uncertainty (Link). The lion’s body reacts the same way to chasing a gazelle as a gazelle’s body reacts to escaping the feline danger. Neither knows if it can succeed. The stress response is a generic mechanism that tells our body and brain to do something. If you try to suppress this instinctive movement, you may feel that as a tremor, tension or agitation. Our perception labels the experience as stressful or exciting. Our bodies don’t. Here lies the key to understanding and harnessing the power of short-term stress. The same excitement at an amusement park that gives us energy and makes us forget about lunch, staying hydrated or work, at a molecular level is mediated by the same mechanisms that are activated when we are faced with a stressful work deadline. Getting used to the physical feeling of short-term stress in our body can help us calm our minds and focus our thoughts on the task at hand — be that completing a work-related task on time or scoring a new high score in a game.

Levels of stress

Short-term or acute stress has numerous protective effects on our life. Short-term stress is indicated by dilation of pupils, increased heart rate, sharpening cognition (Link) and enhancement of immune function (Link). Today, this stress may stem from challenges, arguments, criticism and infections. When adrenaline is released in the body, it gets our blood pumping, our minds focused, our muscles ready and liberates killer cells from immune organs to combat and suppress infection. In procrastination, we use the short-term stress response to our advantage — the impending deadline cues our mind and body to work and we usually deliver on time.

But there are times when constant short periods of stress transition into prolonged periods of stress that can last days, weeks, even months. If we are no longer able to sleep, we are leaving the “good” short-term stress zone behind. The first stop is medium-term stress that can last anywhere from a few days to a couple of weeks. This can tip either way based on our capacity to manage stressful situations. When external pressure exceeds our capacity to manage our stress response, we enter the harmful long-term stress zone.

Long-term stress or chronic stress is the culprit of many conditions. Being able to switch between fight and flight and rest and digest states allows the body to regulate itself and maintain healthy levels of adrenaline and the stress hormone, cortisol. Exposing our bodies to constant fight or flight response, without switching back to rest and digest, can negatively impact our biology. Heart disease risk increases because of the way adrenaline impacts blood vessels (Link). Excessive cortisol coursing through our bodies can increase cravings for calorie-dense foods while decreasing energy expenditure (Link). Moreover, when we are not socially connected enough, the body releases higher levels of tachykinin which can make us feel more irritable, paranoic, fearful and lonely (Link).

How our beliefs impact our stress response and cortisol levels

Psychologist Alia Crum and her colleagues looked at how people’s mindsets around stress impact their responses to stress. They exposed separate groups of employees of a financial institution to two videos: one portraying the stress-is-harmful mindset and the other the stress-is-enhancing mindset. After a week, people who had watched the stress-is-enhancing videos believed that stress has more positive effects. They had better mental health and work performance than the people who watched the stress-is-harmful mindset video (Link).

Crum and colleagues showed that the stress-is-enhancing mindset helped people respond better to stress during a public speaking task with more adaptive cortisol response to stress and more openness to feedback. The researchers observed that the stress-is-enhancing mindset boosts the stress cortisol response for people with low cortisol levels and buffers the cortisol response for people with high cortisol levels (Link). This shows how the right mindset can help us be in a better posture to achieve an optimal level of arousal when under stress and then take the next step towards improvement.

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