Lesson objective:

In this lesson, we learn about the effects of chronic stress on the brain, body and behavior.

The duration of exposure to stress – whether physical or emotional– matters greatly in determining its effects on the overall health and wellness of the stressed individual. 

Short term exposure to stress can result in helpful, adaptive responses like heightened attention for specific tasks, or productive inflammation to treat infection. On the other hand, long-term or repeated exposure to stress can chip away at health and override some of the gains made during short stress exposure. 

As stress grows, hyperarousal–which again, is the activation of various stress response mechanisms in the brain and body for an extended period of time–keeps your mental energy and attention fixated on new possible threats and stressors. 

It makes you hypervigilant to threat, even when there is no threat, or when the threat exists only in the mind. 

And while hypervigilance is an important feature of chronic stress and trauma–and we’ll discuss those in more detail later–the hyperarousal of our systems associated with chronic stress can have many effects on the entire body, on our physical health.

Simply, chronic stress can have profound effects on the whole body, head to toe. 

The effects of chronic stress on the body differ from person to person and are based on the type and degree of stress, age, genetics, life experiences, and the situation itself. 

Your response will vary just as the source of stress varies. 

It is possible that when faced with the same situation twice, you react differently each time. There is not necessarily a “pattern” to how anyone will react to a stressful situation or even to periods of chronic stress.  

In general, the effect of chronic stress and trauma can be seen at three levels–at the level of the brain itself. In the rest of the physical body, and in our behavior. Again, that’s brain, body, behavior. Chronic stress and trauma affect each person across these three levels, and its important that we give each layer due attention, while noting that what we mention here only scratches the surface of the possible effects of stress and trauma. 

We’ll start with the body, then the brain, and then behavior, which encompasses relationships, both with ourselves and others, and our interactions with the world around us. 

In terms of the body, chronic stress affects the cardiovascular system, the respiratory system, sleep, the immune system, and the gastrointestinal system, among others. 

Remember, the brain is also an organ, a part of the physical body. And just as other physical systems like the heart and lungs are affected by stress, the brain as a physical organ is also affected by chronic stress. Indeed, the physical brain changes through chronic stress exposure. Chronic stress can affect both the physical size of certain parts of the brain and also the neural architecture inside those various parts. We’ll get into that after first talking about the rest of the body.

So, as stress increases and the brain and body change, recall that the changes we discuss are all well-intentioned. The brain and body catalyze these changes under the assumption that survival is at stake, even if, ironically, those changes decrease overall health and wellbeing over time. 

In some ways, the effects of chronic stress are highly adaptive for the short term, but pose challenges in the long term. And as we discuss the various negative effects of chronic stress, note that much of what goes wrong can be undone, or at least managed to reduce harmful effects. Where there are negative impacts, there is also the possibility for healing. More on that soon.