Fight, Flight, or Freeze

Sometimes emotions show up in the body intensely, especially when we’re caught off-guard or feel threatened. When we face a dangerous or stressful situation, our brains quickly launch a fight-flight-or-freeze response similar to what animals experience in the wild: when an animal is being chased by a predator, it will instinctively run away, fight back, or freeze.

Creepy big spider crawling right at you? Put on the spot by your teacher when you’re unprepared? Upsetting comments on a social media post? These scenarios are very different, but for all of them, your brain triggers a chain of responses to enable a split-second reaction, even when the situation you’re facing isn’t life-threatening.

During a fight-flight-or-freeze stress response, your adrenal glands pump out a hormone called adrenaline. The surge of adrenaline makes your heart pound, breathing quicken, and muscles tense. Extra oxygen shuttled to your brain makes you super alert and sharpens senses like sight and hearing. Blood sugar and fat spill into the bloodstream to help give you a burst of energy to physically respond.

You might feel these sensations not only in the moment, but also in anticipation of an event like an important exam, a big game, or a performance. After an adrenaline surge, it can take your body a while to calm down and return to its pre-heightened state.

A closer look

Two parts of your nervous system oversee the brain-body loop during a fight-flight-or-freeze response: your sympathetic nervous system quickly readies your body to respond to a threat. Then, much more slowly, your parasympathetic nervous system returns your body to a calmer state.

Here's how part of the relay between your brain and body works:

• The amygdala, the section of the brain that processes emotions in hyperspeed and serves as an alarm system, sends out a distress signal. The hypothalamus fields that signal and tells the autonomic nervous system to get cracking to protect you. This happens in the blink of an eye.
• Your autonomic nervous system has two branches: the sympathetic nervous system and the parasympathetic nervous system. One revs you up, the other calms you down.
• The sympathetic nervous system acts like an accelerator pedal when a threat is detected. If the brain keeps perceiving a threat, the sympathetic nervous system stays engaged and hormones that keep the body revved up and prepped to take action keep pumping.
• The parasympathetic nervous system acts like a brake. When a threat passes, the hormones keeping the body revved up start to fall off and the parasympathetic nervous system steps in to dampen the stress response. You might notice your breathing and heartbeat slow and your muscles begin to feel less tense. The wind-up that gave you energy to act slowly unwinds, a process sometimes called “rest and digest.” Long, slow exhalations help bring the parasympathetic nervous system online.

For more, watch Opens in a new tabThe Fight Flight Freeze Response.

What to try

If you’re experiencing a fight-flight-or freeze reaction, deep breathing exercises (see Breathing exercises) or even a few minutes of sighing can help you calm your body down.

Cyclic sighing

When you’re feeling anxious or stressed, try sighing for five minutes. This helps your body calm down by engaging the part of your nervous system that acts like a brake on the fight-flight-or-freeze response. You can try this almost anywhere.

1. Breathe in through your nose, filling your lungs about halfway. Pause.
2. Then instead of breathing out, inhale through your nose again to fully fill the rest of your lungs.
3. Breathe out very slowly through your mouth.

Repeat these steps for five minutes. Even trying just a few cycles can help.

For a demonstration on cyclic sighing, watch the first 2:30 minutes of a Stanford Medicine Opens in a new tabvideo.