Explainer: What is anxiety?

Similar to fear, anxiety comes from worry about some event that will not kill you — and may not have even occurred


The stress that accompanies school or tests can trigger ongoing feelings of anxiety. But studies show that how we view anxiety can make a big difference in whether this stress helps or hurts us.


Your heart pounds and muscles tense. Sweat beads up on your forehead. These physical reactions signal that the body is stressed and prepared to deal with a potentially life-threatening situation. Sometimes that threat is real. For instance, it might be a coiled snake in your path or a deep chasm you need to cross. Other times, the threat comes from some event that won’t kill you, even though it may challenge your ability to cope. Examples might include taking a test or having to move to a new city. The stress triggered by such non-life-threatening events is known as anxiety.

Anxiety lives in your head. But the stress it triggers affects your whole body every bit as much as does the stress provoked by, say, staring down a hungry lion.

Not surprisingly, anxiety is related to fear. Fear is the emotion we feel when faced with a danger. Fear is also what kept our ancestors alive when a rustle in the bushes turned out to be a hungry lion.

As soon as the brain detects danger, it turns on a cascade of chemical reactions. Nerve cells start signaling one another. The brain releases hormones — chemicals that regulate bodily activities. Fear-triggered hormones ready the body to either fight or flee.

Indeed, turning on this fight-or-flight response is the evolutionary purpose of stress. It triggers some major changes in how the body functions. For instance, blood moves away from the fingers, toes and digestive system. That blood then rushes to large muscles in the arms and legs. There, the blood provides the oxygen and nutrients needed to sustain a fight or to beat a hasty retreat.

a photo of a lion roaring
Our species developed its fight-or-flight response to deal with real threats, such as a lion that our ancestors might have encountered on the savanna in Africa. PHILIPPE ROUZET/ FLICKR (CC BY-NC-ND 2.0)

But sometimes we don’t know whether a threat is real. That rustle in the bushes may not be a lion, just some breeze. Our bodies don’t want to take a chance, so they respond. They prepare us to confront or to flee that possible threat. Your ancestors survived precisely because they reacted, even to what turned out to be false alarms. You might say that evolution has primed people and other animals to be hyper-responsive to certain situations. And that can be a good thing — unless we become too hyper-responsive.

And that’s anxiety. Think of fear as a response to something as it is happening. Anxiety comes from worrying about what may (or may not) happen.

As with fear, anxiety makes us more alert. Our muscles tense. Our hearts beat faster.

Faced with a real life-threatening situation, we would now run away or stand and fight. Anxiety, however, is all about anticipation. There is no actual fight or flight to release us from the strange things happening inside our bodies. So our bodies don’t get to clear away the hormones and brain-signaling compounds (called neurotransmitters) that have been released.

That ongoing response can leave us lightheaded. It happens when our brains are denied the oxygen that is now being sent to our muscles. These reactions also can lead to a stomachache, as our food sits, undigested, in our bellies. And for some, anxiety can lead to a paralyzing inability to cope with life’s stresses.

Everyone experiences anxiety now and again. It’s perfectly normal, for instance, to feel butterflies in your stomach before giving a presentation in front of the class. For some people, however, anxiety can become overwhelming. It can become so disturbing that a person may feel a need to skip school or stop going out with friends. We can even become physically ill.

The good news: Anxiety experts have a number of techniques to help people control such overwhelming feelings.

Power Words

(for more about Power Words, click here)

anxiety A nervous reaction to events causing excessive uneasiness and apprehension. People with anxiety may even develop panic attacks.

chasm  A great or deep gulf or fissure in the ground, such as a crevasse, gorge or breach. Or anything (or any event or situation) that would seem to present a struggle in your attempt to cross to the other side.

evolution (adj. evolutionary) A process by which species undergo changes over time, usually through genetic variation and natural selection. These changes usually result in a new type of organism better suited for its environment than the earlier type. The newer type is not necessarily more “advanced,” just better adapted to the conditions in which it developed.

hormone   (in zoology and medicine)  A chemical produced in a gland and then carried in the bloodstream to another part of the body. Hormones control many important body activities, such as growth. Hormones act by triggering or regulating chemical reactions in the body. (in botany) A chemical that serves as a signaling compound that tells cells of a plant when and how to develop, or when to grow old and die.

hyper-    A prefix that means excessive or exaggerated.

nerves Long, delicate fibers that communicate across the body of an animal. An animal’s backbone contains many nerves, some of which control the movement of its legs or fins, and some of which convey sensations such as hot, cold, pain.

neurotransmitter   A chemical substance that is released at the end of a nerve fiber. It transfers an impulse to another nerve, a muscle cell or some other structure.

stress  (in biology) A factor, such as unusual temperatures, moisture or pollution, that affects the health of a species or ecosystem. (in psychology) A mental, physical, emotional, or behavioral reaction to an event or circumstance, or stressor, that disturbs a person or animal’s usual state of being or places increased demands on a person or animal; psychological stress can be either positive or negative. 

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