The Fight-or-Flight Response: What It Is & How It Aids Survival

This article is an excerpt from the Shortform book guide to "The Upside of Stress" by Kelly McGonigal. Shortform has the world's best summaries and analyses of books you should be reading.

Like this article? Sign up for a free trial here.

What is the fight-or-flight response? How can the fight-or-flight response work against you?

The fight-or-flight response is a physiological reaction to a perception of threat. It mobilizes your physiological resources to prepare you to face danger. However, this response has negative effects, too: when you perceive danger where there isn’t any, you experience unwarranted fear and anxiety.

Keep reading to learn about the psychology of the fight-or-flight response and how it aids survival.

Fight-or-Flight (Threat) Response 

What is the fight-or-flight response? This response occurs when you perceive your life to be in danger. For example, you’re felling a large tree in your yard and when you step back to watch the trunk tip away from you, you notice it’s starting to lean in your direction. Your body surges with energy and you leap clear of the crashing branches.

What Happens When You Fear Your Fear Response?

If your threat response can be triggered by your perception of danger, what happens if you view your own threat response as dangerous? When you view the physical symptoms of your own threat response (such as shaking) as a threat, this leads to a spiral of extreme panic, otherwise known as a panic attack. This response is even more likely when the symptoms of your threat response come on unexpectedly and without an obvious cause. In this case, the physical effects of your threat response may cause you to think something bad is happening to your body and lead you to worry for your safety. 

Although this isn’t considered dangerous, it’s very uncomfortable and can prevent you from performing aspects of your daily routine or attending important events that you think might cause a panic attack. One treatment for panic disorder is cognitive behavioral therapy, which can help you adjust your threat response appropriately for non-threatening triggers.

When your life’s on the line, fight-or-flight equips you for survival in a variety of ways:

  • Your body releases hormones like adrenaline, cortisol, and dopamine to create and distribute more energy, motivate action, and increase your focus on an immediate threat.
  • Your body releases excess stores of sugar and fat into the bloodstream for energy.
  • You breathe harder and your heart starts racing to deliver oxygen, sugar, and fat more efficiently to your muscles.
  • You slow or disable processes like digestion and growth that aren’t necessary for surviving an immediate threat.
  • Your blood vessels constrict and inflammation increases in anticipation of injuries that will need repair.
  • This stress response makes you more aware of and reactive to similar triggers in the future.
Although McGonigal describes multiple aspects of fight-or-flight, she doesn’t cover the phenomena of freezing or fainting, which are also part of a sequence of hard-wired reactions to threats that researchers termed the “defense cascade.” Researchers describe freezing as the early phase of a threat response, which involves a sudden drop in heart rate and body tenseness. This behavior allows you to stop and scan your surroundings before potentially fighting or fleeing. In animal studies, prey commonly uses this response to stay hidden from predators. 

Fainting results from a sudden drop in heart rate and blood pressure, which might happen for a couple of different reasons: during a threat response, your body sends extra blood to your legs to help you launch into action. However, even if you don’t use your legs to get away, this process still draws blood away from your brain, which can cause you to faint. Another theory is that fainting protects your heart from extreme stress responses by effectively shutting down your reaction.

In all these ways, fight-or-flight gives you energy and motivation, and it helps you repair injuries to survive immediate threats at a moment’s notice. However, this response can also be negative: As you process your environment in terms of its potential threat to you, you typically experience negative emotions like fear, shame, and anger.

McGonigal claims that fear and anger characterize your threat response, but research shows that these two emotions are actually associated with separate stress responses. One study claims that anger is likely to result from viewing a situation as low-risk with a sense of confidence and strength. This causes a physical response that includes more energy production and causes less inflammation, which researchers consider a functional response to aggression/confrontation. In contrast, the study claims that fear and shame are likely to result from perceiving a situation as dangerous and risky while feeling more self-doubt. 

Additionally, researchers found that fear was associated with lower energy production and higher inflammation than the anger response. The higher levels of inflammation associated with fear have been associated with shame, which is an emotion that leads to fleeing. So, this study associates fear and shame with a typical fight-or-flight response, as McGonigal does, but it demonstrates that anger is associated with a less defensive, more aggressive response.

Chronic fight-or-flight responses, in which your body frequently reacts with intensity to perceived threats, can cause long-term health effects like faster aging, suppressed immunity, and greater susceptibility to illnesses like cardiovascular disease. 

How Does Chronic Stress Lead to Faster Aging and Disease?  

Chronic stress increases aging by shortening telomeres within cells. Telomeres determine how many times a cell can divide. When telomeres shorten to a certain point, cells can no longer divide and eventually die. This is what prevents our bodies from continuing to heal from cell damage and illnesses like cardiovascular disease. 

However, shortened telomeres are not all bad. In fact, one study found that shortened telomeres decrease your risk of cancer by limiting rapid cell division. This study concluded that long and short telomeres pose a near equal level of health risk, with longer telomeres increasing the likelihood of cancer and shorter telomeres increasing the likelihood of illnesses like heart disease and Alzheimer’s.
The Fight-or-Flight Response: What It Is & How It Aids Survival

———End of Preview———

Like what you just read? Read the rest of the world's best book summary and analysis of Kelly McGonigal's "The Upside of Stress" at Shortform.

Here's what you'll find in our full The Upside of Stress summary:

  • Why stress is an ally that should be embraced
  • How stress can lead to enhanced health, greater success, and a more meaningful life
  • How to change your mindset about stress to receive its benefits

Darya Sinusoid

Darya’s love for reading started with fantasy novels (The LOTR trilogy is still her all-time-favorite). Growing up, however, she found herself transitioning to non-fiction, psychological, and self-help books. She has a degree in Psychology and a deep passion for the subject. She likes reading research-informed books that distill the workings of the human brain/mind/consciousness and thinking of ways to apply the insights to her own life. Some of her favorites include Thinking, Fast and Slow, How We Decide, and The Wisdom of the Enneagram.

Leave a Reply

Your email address will not be published.