The Science of Stress

What causes stress reactivity and how can it be managed?

Posted Dec 22, 2020

Source: Ataner007/Pixabay

Consider these two statements:

  1. Stress is good for you: Stress motivates you and helps you stay alert and focused.
  2. Stress is the silent killer: Stress causes irritability, fatigue, sickness, and death.

Which of the above is true?

The answer depends not just on the stressors themselves but also on how we react to stress.

In this article, I summarize key points from a paper by Kiecolt-Glaser et al., published in the October 2020 issue of Current Directions in Psychological Science, which reviews factors affecting stress reactivity. I end by discussing effective coping and techniques for managing stress reactivity.

Good stress and bad stress

Let me begin with a question: What is the stress response (aka the fight-or-flight response)?

The fight-or-flight response is the body’s response to stress. Mediated by the sympathetic nervous system, the fight-or-flight response is associated with a series of complex physiological reactions, like increased breathing rate, higher blood pressure, reduced heart rate variability (HRV), redirection of blood flow to skeletal muscles, elevated blood sugar, and changes in the levels of cortisol, epinephrine, and other hormones.

An optimal stress response is one that occurs quickly, is proportional to the threat, and halts soon after the challenge has been met. To illustrate, a response to a knife-wielding maniac is adaptive only if it quickly prepares the body to fight or run away, and if it subsides soon after the threat is gone.

In contrast, when, say, a hurtful comment triggers long-lasting and intense physiological or psychological reactions, the stress response is dysfunctional and maladaptive.

When this maladaptive stress response occurs regularly, it causes health conditions associated with chronic stress.

How? In part through increased inflammation. Chronic inflammation has been linked to numerous health conditions: Heart disease, diabetes, arthritis, asthma, chronic pain, depression, and metabolic syndrome—high abdominal obesity, blood pressure, blood sugar, and cholesterol.

Individual stress reactivity

A variety of individual-level factors affect stress activity.

For instance, depression worsens stress reactivity; however, the opposite also occurs: Greater stress reactivity increases inflammation and worsens depression.

Even a history of depression is linked with greater stress reactivity. Why?

The scar theory of depression suggests major depressive episodes (e.g. in reaction to the loss of a parent) leave behind “scars.” These scars sensitize the individual and increase the likelihood that comparably minor events (e.g. changing schools) will trigger episodes of depression.

Mood disorders may, when combined with heightened stress response, influence other aspects of well-being as well. For instance, they can result in weight gain. Kiecolt-Glaser found that adults with a history of mood disorders who were more hostile during marital conflict discussions as well had decreased postmeal resting energy expenditure—equivalent to a weight gain of nearly eight pounds (if sustained for a year).

Other individual-level influences on stress include cognitive factors: Rumination, worry, and anticipatory anxiety. These often prolong or worsen physiological arousal, meaning they result in higher blood pressure and cortisol levels, and worse HRV reactions.

Last, in terms of the effects of early life adversity, the Biological Embedding Model suggests stressful experiences like childhood abuse and trauma are “programmed” into immune cells involved in the inflammatory response, making them more reactive to stress. Therefore, individuals who have experienced childhood abuse might have greater stress reactivity even many years after the maltreatment ended.

Interpersonal stress reactivity

People also influence the stress reactivity of others, such as their romantic partners. How?

During interactions, romantic partners’ stress levels may synchronize, and, over time, partners could begin to respond in a more similar way to the same stressors.

Of course, couples can influence each other positively too. Positive relationships are characterized by mutual validation and support, which help reduce stress reactivity. In contrast, negative relationships are characterized by frequent conflict and hostility (e.g., eye-rolling, sarcasm). And, as it occurs in some unhappy marriages, sometimes romantic partners become stuck in a negative cycle of violence and abuse, which results in increased stress reactivity and a greater chance of developing a mental illness.

Research by the authors of the current review found that compared with less hostile pairs, newlyweds who expressed more hostility during marital discussions showed higher levels of stress hormones such as epinephrine. More importantly, “Postconflict epinephrine in the first year of marriage was 34% higher in couples who subsequently divorced than [ones] still married 10 years later.”

Techniques for managing stress reactivity

In summary, greater stress reactivity results in physiological dysregulation, which is associated with chronic diseases like heart disease, autoimmune disorders, and clinical depression. These conditions often have a negative effect on stress reactivity. This results in a vicious cycle that worsens systemic inflammation, immune functioning, and chronic diseases, and contributes to frailty, accelerated aging, and possibly early mortality.  See Figure 1.

Arash Emamzadeh (adapted from Kiecolt-Glaser et al., 2020)
Source: Arash Emamzadeh (adapted from Kiecolt-Glaser et al., 2020)

What can we do to break this vicious cycle?

Managing stress reactivity requires learning about factors that influence the stress response, and then identifying and altering modifiable influences on stress, such as unhealthy thinking patterns (e.g., rumination, worry) and dysfunctional communication patterns (e.g., sarcasm, insults).

As for reducing stress reactivity more directly, one possibility is to stimulate the parasympathetic nervous system (e.g., using breathing techniques) to counterbalance the effect of the sympathetic nervous system.

Popular stress management techniques—contemplative practices such as yoga and mindfulness meditation—may also reduce stress reactivity.

For instance, in one investigation, experienced yoga practitioners had lower levels of IL-6 (an inflammatory marker) when compared to yoga practitioners with less experience. And a meta-analysis concluded meditation is associated with reduced markers of stress—reduced cortisol, blood pressure, and C-reactive protein (an inflammatory marker).

Last, as the authors note, aside from meditation, “exercise, a healthy diet low in sugar and saturated fats, and regular high-quality sleep may also reduce stress reactivity as well as depressive symptoms.”