JUANA SUMMERS, HOST:
Americans are anxious. Nearly three years of a pandemic, political unrest and ongoing economic instability have left people feeling fearful, ill at ease. This week, we're spending some time understanding anxiety. We will kick off the series with a simple question - what is anxiety? NPR's health correspondent Rhitu Chatterjee went looking for the answer and brings us this story.
RHITU CHATTERJEE, BYLINE: Most of us have experienced anxiety at some point in our lives, and we know how it shows up in our bodies - racing thoughts, struggling to sit still, queasy stomach, sensations that bring a sense of dread. Psychologist Bunmi Olatunji studies anxiety at Vanderbilt University.
BUNMI OLATUNJI: Anxiety is a feeling of nervousness and apprehension, and usually that feeling is in response to an anticipated threat.
CHATTERJEE: Take, for example, the pandemic, which brought the threat of disease. And while we may not enjoy feeling anxious, Olatunji says it's a normal and extremely useful emotion.
OLATUNJI: If you're anxious about something, that's motivation to either problem-solve or to do something about it.
CHATTERJEE: In other words, anxiety can be adaptive. That's why researchers think that it probably played a key role in human evolution because it alerted our ancestors to threats in their environment. Ed Hagen studies the evolution of emotions and mental illnesses at Washington State University.
ED HAGEN: And if you look at the kinds of things that people tend to be anxious about, they do seem to line up with those kinds of longstanding evolutionary threats.
CHATTERJEE: Like predators, poisonous foods and animals, disease and even social threats.
HAGEN: Most of us are, you know, really concerned that we maintain a good reputation with our friends and group members.
CHATTERJEE: Because being in a group meant physical safety and a higher chance of survival. These days, though, most people aren't fending off predators or foraging for food, but our anxiety is still warning us about modern-day threats. Wendy Mendes is at the University of California, San Francisco, and studies how emotions play out in our bodies. She says anxiety tends to rev up one part of our nervous system.
WENDY MENDES: In anxiety, you often will have an activation of the sympathetic nervous system.
CHATTERJEE: The sympathetic arm of the nervous system kickstarts our fight-or-flight response.
MENDES: It's part of that vigilance by monitoring the environment for threats.
CHATTERJEE: Our muscles tighten. Our heart rates go up as we prepare to fight the threat or run from it. But this activation also suppresses another key part of the nervous system - the parasympathetic nerves.
MENDES: As your parasympathetic system tells you, I'm hungry, I'm going to digest food, it affects your sleep - can't go to sleep when your parasympathetic system is suppressed.
CHATTERJEE: All that's helpful in the short term because it focuses all the body's resources on dealing with the threat. But then there are also situations that can put people in a heightened state of anxiety for longer periods of time, for example, a major traumatic event or chronic stresses like community violence or ongoing medical or financial problems. Mendes says when this short-term warning system that's anxiety starts to linger on, that's when it starts to become harmful.
MENDES: Think of it as, you know, constant pressure on a system. It's like if you only could breathe in and you could never breathe out.
CHATTERJEE: Research shows that chronic anxiety puts people at a higher risk of a range of physical health problems - insomnia, spikes in blood sugar levels, high blood pressure, cardiovascular disease. And prolonged, heightened anxiety could also become an anxiety disorder. Psychologist Elissa Epel is at the University of California, San Francisco.
ELISSA EPEL: Anxiety disorders develop when we start avoiding situations in life. This avoidance is what creates the disorder. It disrupts our life.
CHATTERJEE: Epel says there are good treatments for anxiety disorders. However, most people dealing with everyday anxiety probably don't meet the criteria for that. But their anxiety can still be high and erode away their health and quality of life.
EPEL: In this modern environment, when our mind is overtaxed with stimulation, our sensory system is overloaded, we don't tend to notice that we're carrying around anxiety.
CHATTERJEE: That's why Epel says it's important to pay attention to our anxiety and the little everyday threats it's telling us about, so we can address them in the moment and keep our anxiety in check so it doesn't take over our lives.
Rhitu Chatterjee, NPR News.
SUMMERS: And later this week, Rhitu will bring us tips and tools to manage anxiety. Transcript provided by NPR, Copyright NPR.