They can begin suddenly and peak quickly, with their signature trembling, nausea, and ragged breaths rolling in waves. A panic attack is your body your body being gripped with fear, but what triggers that fear and how often it takes hold of you depends on who you are. The stimuli vary from person to person, but what remains constant is the experience itself — and its prevalence among humans. Most people, at some point in their lives, will experience a panic attack because it’s an adaptive response brought about by human evolution.

“Panic attacks themselves are not unusual,” Raphael Rose, Ph.D.. the associate director of the Anxiety and Depression Research Center at the University of California, Los Angeles, tells Inverse. “Anyone can have a panic attack, and often people will have one or two panic attacks at some point in their lifetime. While panic attacks are not uncommon and an isolated one is usually not a problem, they can be distressing and lead to problems like panic disorder.”

Rose explained to Inverse that there’s a nuanced distinction between experiencing panic attacks and being diagnosed with a panic disorder and that the experience and the consequences that can come along with it are all a part of human evolution. Based on that conversation and other research, the guide below tells you what goes down when panic sets in.

Panic attack
Most people will have a panic attack once or twice in their lifetime.

What is a panic attack?

The Mayo Clinic defines a panic attack as “a sudden episode of intense fear that triggers severe physical reactions when there is no real danger or apparent cause.” If you’ve gone through a panic attack, you might think of it as fresh hell that’s come to make you feel miserable. Sometimes, it can peak within 10 minutes or less from its outset. Other times, distinct episodes can come and go in waves over the course of several hours.

Although it can sometimes feel like the attack comes out of nowhere, in 2011 scientists from Southern Methodist University found that people actually go through about one hour of significant physiological instability before a panic attack settles in. A true panic attack includes four or more of categorized symptoms, whereas a “limited symptom attack” involves three or less. These include but aren’t limited to a fear of dying, a fear of insanity, dizziness, an increased heart rate, a sense of being detached from oneself, and chills.

Physiologically, the body’s sympathetic nervous system (responsible for the “fight or flight” response) gets activated as the parasympathetic nervous system (“rest and digest”) is put on hold. This is the root cause of the rise in blood pressure, heart and breath rate during a panic attack. Parts of the brain become hyperactive as well, in particular the areas of the brain called the periaqueductal gray and the amygdala, which control the brain’s autonomic responses to fear. Rose explains that this process, culminating in the body harvesting energy for fight or flight, is why some people may feel so exhausted after a panic attack.

Amygdala
The amygdala controls autonomic responses associated with fear.

What is panic disorder?

A single panic attack does not a panic disorder make. People diagnosed with a panic disorder meet specific criteria developed by experts, which include recurrent, unexpected panic attacks but also long periods of fear that another attack will strike — in other words, an intense fear of panic attacks. According to the University of Pennsylvania’s Center for the Treatment and Study of Anxiety, approximately two to three percent of Americans have panic disorder at some point in their lives.

“People who develop a panic disorder begin to fear those physiological effects and essentially what you have is a fear of fear,” says Rose. “There’s a belief that those symptoms are dangerous — they might think they’ll go crazy or they’ll have a heart attack. A person who has a panic attack can move on, but those with panic disorder can turn inward and are overly focused on the sensations.”

stress
Panic attacks can be triggered by many things.

Why do panic attacks happen?

A panic attack can be spurred by anything: a physically and emotionally traumatic event, like going through a car crash; a psychologically threatening one, like a public presentation; or even rumination on more chronic anxieties, like work or financial stress. It really depends on the person, and if that person is diagnosed with a panic disorder, experts study their individual characteristics in order to treat them in highly specific ways. Genetics as well as environmental and stress factors also come into play, meaning that some people are more prone to panic attacks than others.

“The tricky thing with panic attacks is that something can be clearly triggering it, or it’s possible there can be no clear causative event,” says Rose. “The experience of panic shares many similarities across individuals, while what triggers a panic attack can vary across people.”

Rose says it stands to reason that panic attacks have an evolutionary basis. Panic is a form of fear, and fear is an adaptation that allowed our ancestors to pass on their genes: The ancient human that was afraid of the sabertooth tiger, after all, was much more likely to survive and have offspring than the one who stepped up to pet it. Panic attacks, according to some psychiatrists, are a fear response to a stimulus that feels threatening but isn’t actually as dangerous as, say, that sabertooth tiger.

“The main idea behind fear is that it’s there to protect us, and therefore, it is adaptive,” says Rose. “What we don’t have is a fear response for a sabertooth tiger and a different fear response for a public speaking situation. It’s the same and, accordingly, it can be activated in a way that might seem disproportionate to the threat. But our body is still perceiving a threat and reacts with the strong, intense experience of fear.”

Rose explains that our “relatively thin-skinned” existence has been what’s helped us survive to be at the top of the food chain. We need to protect our selves physically and socially — and that’s likely why the threat of failing in social situation can cause such a smack of fear to the heart.

worried person
Doctors recommend sticking to a treatment plan to help the worsening of panic attacks.

How can you stop a panic attack?

There’s no definitive way to stop panic attacks from happening, but doctors recommend sticking to regular physical activity to alleviate anxiety and reducing caffeine intake. Treatment is possible: Rose believes the best results come from cognitive behavioral therapy (CBT), a type of therapy in which a psychotherapist or therapist helps the patient respond to what causes them fear in a more effective way. Often, CBT encourages patients to lean into what makes them uncomfortable and learn that fear is something they can overcome.

“When we’re treating panic disorder, we’re trying to get people to see that while panic is uncomfortable, it’s not dangerous,” says Rose. “There’s actually nothing you need to do to get rid of it, and nothing to fear about it, and that’s the main point of the treatment for panic disorder.”