F3 or the Fight-Flight-Freeze response is the body’s automatic, built-in system designed to protect us from threat or danger. For example, when you hear the words, “look out!” you may be surprised to find how fast you move, and thankfully so, as you narrowly miss a flying puck sailing through your kitchen window! Or when you see a bear on the trail up ahead, you stop and remain quiet and still until it moves on. In both scenarios your system demonstrates its effectiveness at protecting you from danger.

The F3 system is critical to our survival from true threat or danger, but what happens when there is no real danger? Interestingly, anxiety can also trigger this system into action when we believe there is threat or danger even if there is not. For example, you may yell at your partner for pushing you into agreeing to speak at a conference when you don’t feel ready (fight). Or you avoid going to a party or leave early because you don’t feel comfortable around unfamiliar people (flight). Or, your mind goes blank when your boss asks you a question (freeze). All of these are examples that can cause anxiety, which in turn, can mistakenly trigger the Falarm. Public speaking, parties, and answering questions are not dangerous situations, but if your alarm system is set to “high alert” it will go off even in relatively harmless situations.

Learn more about some of the common changes your body can make to protect you from danger by reading the below:


When you breathe too fast or too deep, you may feel a little lightheaded. This is called hyperventilating. Don’t worry. It’s not dangerous! Your body is just trying to get more oxygen and blood to your large muscles so you can fight, run, or hold still.


When you are confronted with danger, your pupils get bigger to let in more light so you can better spot the danger. This can make things seem brighter or fuzzier, and you may even see some black spots or other visual effects.


When you are faced with danger, blood from your fingers starts to move towards bigger muscles, like your biceps. These bigger muscles need energy to help you fight or run. Your fingers may feel numb, cold, or tingly as blood moves away from them.

Arm Muscles

When faced with danger, your body tenses up, so you are ready to spring into action. The muscles in your arms tense up so you can strike out at danger, pull yourself away, or hold still.

Sweat Glands

Your body works hard to help you get ready for danger. It takes a lot of energy, which can cause your body to heat up. Sweat from your underarms, palms, or forehead cools down your body.


When your body is preparing itself for action, it makes sure blood and oxygen is pumped to major muscles like your biceps or thighs. This gives you energy and power to strike out at danger or to run away as fast as you can.


When your body thinks you are in danger, it puts all its resources into protecting you. Other systems in your body (like your digestive system) slow down, because your body thinks giving you energy to deal with the danger is more important than digesting that sandwich you had for lunch. Of course, this means you might get an upset or sore stomach from that sandwich sitting in stomach acid while it waits to be digested once the danger passes.

Thigh Muscles

When faced with danger, your body tenses up, so you are ready to spring into action. The muscles in your legs tense up so you can run away, fight back by kicking, or hold still.