In the next four sections, I will discuss anxiety from a biological and evolutionary perspective.
Stress and anxiety are often associated with the clamor or modern life. Yet, "stress" is ancient. Most animals have a stress response. The "anatomy" or biochemistry (if not the triggers of stress) has similar features across many mammals. For us humans, anxiety is complicated. Some is useful if it leads to motivation to perform a task. Anxiety, we must remember is at times appropriate. It helps us act to diminish fear. We may not enjoy algebra, but the anxiety associated with failing a high school exam might motivate us to study harder. Usually, however, we get it when we don't want it. Anxiety can prevent us from getting a good night's sleep. It can lead to mental anguish. It can even ruin our concentration and prevent us from being functional. Yet it has its roots in evolutionary biology
You may have heard of the phrase "fight-or-flight". What is it? For one thing it is an evolutionary gift and we wouldn't be here without it. It is our natural "panic button." In the earliest period of our evolutionary life, the "fight-or-flight" response allowed us to flee from a predator (or rile ourselves up to pounce on prey). How does this biological response work so rapidly? The "fight-or-flight" response marshals a number of our body's most powerful systems: biochemical, cardiovascular and neurochemical, then rapidly strings them together, all in the service of pouncing on potential food or fleeing from a predator. If a saber tooth tiger purrs in the bush, we need to run, think clearly, become agile --- and do all of this immediately Almost instantly our pupils dilate (allowing in more light), our heart rate increases (allowing us to circulate more blood and oxygen to our heart and lungs) and our respiratory rate increases (preparing us to become physically active).
By now, you might be asking: what does this have to do with anxiety? Well, both the hallmark of acute anxiety and the "fight-or-flight" response is the rapid movement from a relaxed state to a stressed state. Indeed, many researchers believe that spikes in anxiety (or panic for that matter) are, in part, derived from the same evolutionary origins as the "fight-or-flight" mechanism. In the bush, the stress response might be useful for safety. Its present day vestiges can be destructive in the setting of modern sedentary life. Being plagued with anxiety in the middle of the workday, before a meeting or while lying in bed staring straight in the air anxiously ruminating is not helpful. By understanding some of the evolutionary origins of some of our anxiety, we can better understand the rapidity with which it envelops us. We also gain an inkling into how our breathing and heart rate fit into the picture of anxiety. This link between the "fight-and flight" mechanism and our modern day worries and anxieties is in important. From this point of departure we can learn a lot about ourselves as well as how to treat anxiety conditions.
Anxiety has multiple origins. Yet, it is important to keep in mind that it has some origins in evolutionary biology. Often, acute anxiety is not simply a matter of mental anguish. Rather our bodies become physically revved up. This helps us understand why we often can't simply "think" our way out of anxiety. Our biology has entered an active state. As we will see, understanding this aspect of anxiety becomes important in treating it.