How Norepinephrine and Endorphins Whack Depression
Author: Kate Findley
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By Peter M. Vishton, PhD, William & Mary
Edited by Kate Findley and proofread by Angela Shoemaker, The Great Courses Daily
Researchers have found that arousal can help you overcome depression, and exercise seems to have the same effect on the brain as a selective serotonin reuptake inhibitor (SSRI) drug. Why is that? Professor Vishton explains.
What Are Endorphins?
How is it that exercise can be as powerful a tool for overcoming depression as SSRIs? Researchers have found evidence for several different answers to this question. One possibility is that, during physical activity, our brains produce extra neurotransmitters such as endorphins which can help lower depression.
Endorphins are neurotransmitters associated with the regulation of pain perception. When your body is physically damaged, our brain computes a perception of pain.
If you are running or biking, the consistent, repetitive stress placed on the muscles results in damage and a pain perception associated with it. Just to be clear, this exercise-induced damage, in this case, is a good thing.
Exercise stresses and damages those muscles. As you recover from that damage, your muscles repair themselves and, in addition, make themselves a little stronger than they were before the exercise.
The homeostasis concept applies here as well. If you feel a consistent amount of pain, your brain takes steps to reduce it. Endorphins are released, which inhibit the brain’s response to that discomfort.
How Physical Pain Mitigates Depression
Imagine you are exercising. You are out for a 30-minute jog or walk. As you repeatedly stride forward, you fatigue—and damage—your muscles.
Your brain starts to produce endorphins to counteract the painful effects of this. Thirty minutes later, you stop.
What happens to those endorphins? Eventually, the endorphin production drops again, but not immediately.
For a while—many minutes in some cases—those endorphins continue to be produced and continue to influence the brain. Many people report a feeling of great pleasure when this is happening. Colloquially, this is sometimes referred to as the runner’s high.
A painful stimulus plus endorphins equals homeostasis; you’re at that normal state. When you stop exercising, the painful stimulus is gone.
Nothing plus endorphins equals pleasure. It’s almost as if, for a few minutes, you have taken a mild dose of morphine. The endorphins don’t seem to merely dull the physical pain of exercise but to also dull the mental and emotional pain of depression.
Norepinephrine and Exercise
In fact, a variety of other neurotransmitter systems are also activated by exercise. Norepinephrine, for instance, is produced much more during physical activity than during periods of rest.
This norepinephrine neurotransmitter is the one that increases general arousal for the sake of physical activity, actually. For example, it’s involved in increasing activity in the heart and lungs when you start moving around. It also plays a large role in regulating general respiration, heart rate, and sweating.
Like the endorphins, even after you stop exercising, the production of norepinephrine continues for a while. As it increases your level of physical activation, it will reduce the effects of depression.
Therefore, exercise may be painful at times, especially if you’re engaging in intensive activity or haven’t worked out in a while, but it is ultimately rewarding. It boosts the production of certain mood-elevating neurotransmitters including endorphins and norepinephrine, which in turn can reduce depression.
Peter M. Vishton is Associate Professor of Psychology at William & Mary. He earned his PhD in Psychology and Cognitive Science from Cornell University. Before joining the faculty of William & Mary, he taught at Northwestern University and served as the program director for developmental and learning sciences at the National Science Foundation.