Increased heart rate. Heavy breathing. Maybe even sweating hands.

These can be symptoms of the fight-or-flight response, your body’s physiological reaction to perceived physical or mental threats. Generally speaking, these are signs of anxiety, your body’s reaction to stress. This type of anxiety is normal and can be expected to hit during certain life events and can last for brief periods of time.

However, individuals with anxiety disorders often experience these intense emotions for prolonged periods of time, which can impact their day-to-day living. There are several types of anxiety disorders, including generalized anxiety disorder, panic disorder and phobia-related disorders, like social anxiety disorder. And while each type has unique symptoms, generalized anxiety disorder (GAD) is the most common and will often involve persistent worries regarding nonspecific life events and situations.

“Anxiety is the most common mental health condition seen in our society,” explains Danesh Alam, MD, medical director of Behavioral Health Services at Northwestern Medicine Central DuPage Hospital.

Symptoms of anxiety disorders are thought to be a disruption of the emotional processing center in the brain rather than the higher cognitive centers. The brain’s limbic system, comprised of the hippocampus, amygdala, hypothalamus and thalamus, is responsible for the majority of emotional processing. Individuals with an anxiety disorder may have heightened activity in these areas.

“Anxiety can be severely debilitating and good treatments are available,” says Dr. Alam. Ways to cope with anxiety include medication, therapy and lifestyle changes.

Make sure to make time for your mental health. As you can see, there’s more than meets the eye when it comes to the science behind anxiety.