(NewsUSA) - Stress and anxiety form normal parts of the human experience. Seven out of every 10 Americans report feeling stressed or anxious every day.

But in an age when most Americans, according to a survey by Anxiety Disorders Association of America (ADAA), feel stress and anxiety so severe that it interferes with daily life, people will need to learn to distinguish between normal stress levels and anxiety disorders.

Anxiety is a normal reaction when something isn't right. But the 40 million U.S. adults with an anxiety disorder experience persistent, irrational and overwhelming anxiety that interferes with daily life.

"'Anxiety disorders' is the term used to include generalized anxiety disorder (GAD), obsessive-compulsive disorder (OCD), panic disorder, posttraumatic stress disorder (PTSD), social anxiety disorder or social phobia, and specific phobias," said ADAA President and CEO Jerilyn Ross, MA, LICSW. "They are the most common mental illnesses in the U.S."

Completely eliminating stress proves impossible, but people can learn to manage their stress through lifestyle changes. For example, regular exercise helps ease anxiety. Some studies show that exercise can work quickly to elevate depressed moods in many people. A brisk walk or other simple activity can deliver several hours of relief, similar to taking an aspirin for a headache.

Regular aerobic exercise has been shown to decrease overall levels of tension, elevate and stabilize mood and improve sleep and self-esteem. Science has also provided some evidence showing that physically active people have lower rates of anxiety and depression than sedentary people. That's why exercise is an integral part of every treatment program recommended by Ross.

"People may feel powerless in terms of home life, finances or politics, but they're in control when they exercise," said Ross.