I was in the middle of a workout class when, out of nowhere, I felt it—a pressure blooming in my chest. My breathing started to become heavier, and not from exertion. Tears began to prick the back of my eyes. I knew exactly what was happening; I was on the cusp of a panic attack. And besides being freaked out, I was really confused. Sure, maybe I was a little more stressed about work, but there was nothing out of the ordinary going on in my life that would warrant such a strong emotional (and physical) reaction.

And that’s the insidious thing about anxiety and panic disorders—there oftentimes isn’t anything rational about it. “The definition of anxiety is, to some degree, an irrational fear or danger reaction to something that actually isn’t that level of dangerous or fearful,” says Gail Saltz, MD, the associate professor of psychiatry at the NY Presbyterian Hospital Weill-Cornell School of Medicine. Sometimes it manifests in a panic attack, or vomiting, or sweaty palms. But what triggers these different physical symptoms of anxiety? I asked Dr. Saltz to explain.

Our bodies have a natural fight-or-flight response when faced with potential dangers. This reaction is great when we need to, say, run away from a T-Rex should you be in a Jurassic Park—esque situation. But Dr. Saltz says that when you experience anxiety, your sympathetic nerve system (which controls that above-mentioned fight-or-flight response) overreacts. Your body gets this rush of norepinephrine, which is a stress hormone and neurotransmitter that increases your alertness, speeds up your heart rate, and tells your body to increase blood flow away from non-essential areas to your muscles (so you can more quickly run away). This isn’t necessarily a bad thing per se…except there is no clear external threat warranting such a response.

This influx of norepinephrine can trigger a variety of physical responses. Dr. Saltz says the most common are sweating, rapid heartbeat, nausea, feeling jittery or “tingly,” and shortness of breath. “The reaction of the sympathetic nervous system makes one symptom more predominant for some people than others, but it isn’t really known why exactly this is,” she says. This is also why it can be difficult to tell if shortness of breath is from anxiety or something else, for example.

Physical symptoms vary from person to person, but certain types of anxiety are more likely to trigger certain symptoms. Panic attacks generally trigger very severe physical symptoms, while Dr. Saltz says that some people experience anxiety without having any sweaty palms, nausea, or heavy breathing. “It’s all in their thoughts,” she says. Basically, our sympathetic nervous system reacts pretty much the same in terms of anxiety—but the physical symptoms that it triggers will vary from person to person.

Ah, anxiety. So fun. I’m going to go look at pictures of Jeff Goldblum to decompress now. Highly recommend.

Got anxiety? Send this cheat sheet to your partner to help them be effectively supportive. Then, see if acupuncture can help you manage your anxiety.