Depression is draining. It can make any type of exertion -- going to the grocery store, cleaning up the yard, or exercising -- seem daunting.
"Energy loss is one of the key characteristics of depression. Some people feel that it’s the key characteristic of depression," says Robert E. Thayer, PhD, a psychology professor at California State University, Long Beach, an expert in managing mood, and the author of Calm Energy: How People Regulate Mood with Food and Exercise.
Serotonin acts as a neurotransmitter, a type of chemical that helps relay signals from one area of the brain to another. Although serotonin is manufactured in the brain, where it performs its primary functions, some 90% of our serotonin supply is found in the digestive tract and in blood platelets.
Can depressed people get into a vicious cycle if they feel stressed and overeat and don’t exercise and then become more depressed?
"Definitely. People self-regulate with food, and I think that’s one of the reasons for the obesity epidemic that’s occurring -- the combination of increased stress and depression going on for a long time and people needing to self-regulate, using food and other substances for doing that."
If depressed people begin to exercise instead, what happens physiologically?
"There’s a whole series of things that happen when we begin to exercise. As we get up and begin to move and exercise, there’s a general bodily arousal state that occurs. It includes many different systems of the body -- everything from metabolism to cardiovascular activation, various kinds of endocrine changes in the brain, various kinds of hormonal changes and shifts."
What happens psychologically when people start to exercise?
"It depends on the degree and level of exercise. With moderate exercise, [in our research] we’ve been working with short, brisk walks [of] five or 10 minutes. The primary mood effect in that situation is increased energy. Secondarily, sometimes -- but not always -- there’s a tension reduction."
"With more intense exercise -- for example, an hour of heavy aerobic exercise -- there is a reduction in energy and a reduction in tension. But oftentimes, after recovery [from the workout], there’s an energy resurgence that occurs."