Psychology Today: Can Exercise Prevent Depression?

In working with patients who are subject to bouts with depression, I usually try to encourage them to make even limited but regular exercise sessions a priority.  Self-care can generally be helpful in fighting depression, and just the discipline of organizing one’s life around an activity that is a break from stress can contribute to a virtuous cycle of healthier living.  The excerpt below (emphases in bold italics are mine) discusses a very large prospective research study that suggests that “even a brief but regular schedule of light activity may lower the chances of developing depression.”  That’s an important precept for all of us, whether we’re currently disposed toward depression or not.

Psychology Today: Can Exercise Prevent Depression?

By Emily Deans M.D.

A long-term study suggests a surprising amount of exercise might help.

Oct 07, 2017

Exercise and fresh air have always been folk prescriptions for a glum mood….But clinical depression is a different story—could regular exercise prevent a full on depressive episode from occurring? Researchers aimed to find out in a study published this week online in the American Journal of Psychiatry.

Here’s the theory of how exercise might help treat or prevent depression or anxiety: We’ve pretty much settled that a lot of clinical depression and anxiety are caused by chronic or severe acute stress, leading to a state of inflammation in the body and brain. When it comes to physiology, this means the sympathetic “fight or flight” nervous system is activated too strongly for too long, and the parasympathetic “rest and digest” nervous system doesn’t come online robustly enough to undo all the stress from the “fight or flight” overactivity. Exercise, via parasympathetic vasovagal activation during the recovery period, can, in real time, strengthen that “rest and digest” action. However, you need quite a bit of exercise to really engage the parasympathetic recovery: To get the famous “endorphin” effect you need quite a bit of high-intensity exercise, like a long and fast run, and for a pharmacologic effect it would need to be fairly frequent. In theory, exercise should work better for anxiety, which is more directly related to stress, than for clinical depression (though the two often come together).

So what did the researchers in the HUNT [Cohort Study] protocol do? They designed a very large prospective study following thousands of participants in Norway for 9-13 years. The subjects were found by inviting the population of an entire county, aged 20 or older, to fill out a basic screening form for depression and anxiety. The happiest 70% were asked to participate in order to get a healthy baseline (and an additional 8,400 or so were excluded for serious physical illness), and of those, nearly 34,000 were included in the study. Other data, such as smoking status, social supports, BMI, resting heart rate, and demographic data were collected at various visits over the years. All in all about 22,500 completed the study….

Once all the numbers were crunched, the researchers ended up with a surprising finding. Those who exercised were, indeed, less likely to develop depression over those 9-13 years than those who didn’t. The weird thing is, it didn’t matter how much exercise as long as you did some deliberate physical activity for at least an hour each week. Yes, that’s right, only one hour total for the entire week. And it also didn’t matter how intense that exercise was…could be a walk in the park or three sessions of intense spinning class or a daily 5K run. This finding belies the “parasympathetic vasovagal reactivity” theory of how exercise might prevent depression by stopping the sympathetic overactivity that characterizes the disease. Also, exercise was not related to lower risk for the development of anxiety disorders—only depression….

…. The researchers postulate that it’s the social benefits of exercise—getting out and about, feeling good about oneself, self care, that sort of thing—that may make the real difference, though the number-crunchers felt that a lot of the mechanism and wherefore and whys remain unexplained. We also know that people who develop a clinical depression have less get up and go, less motivation, less of the frontal lobe’s saying “get out of bed and get to the gym,” so once a depression kicks in, exercise is likely to drop as a matter of course. The same isn’t really true for anxiety.

Also, straight up parasympathetic training and sprint intervals aren’t the likely mechanism for preventing depression or anxiety, but anyone is welcome to do these more intense exercises for other reasons.

….This data suggests that keeping up even a brief but regular schedule of light activity may lower the chances of developing depression in the future…. Twelve percent of depression cases prevented? That’s a significant amount, and you may not have to be a gym rat to make it happen.

 

New York Magazine: Psychologists Think They Found the Purpose of Depression

Students of evolution have long wondered which psychological profiles provide an evolutionary advantage to an individual, group, or species, a question whose complexity is compounded in the study of human history by the observation that many of those who have achieved notable successes within societies  — and who have survived to pass along their genetic material — nevertheless evidence major psychological weaknesses and pathologies in their psyches.  In other words, what might be evolutionarily limiting, even fatal, for a species, may seem to be beneficial, at least in the short term, for individuals and families….This line of questioning has lead some psychologists to wonder whether certain psychological pathologies, despite being being exactly that — illnesses to be combated — are nevertheless a form of the human animal trying to help itself become healthier by prompting a self-healing reaction.  The excerpt below summarizes an article which discusses some of research being done in this fascinating area of enquiry, focusing on depression as viewed through this theory: depression as a state in which the body is trying to tell an individual to take therapeutic steps toward healing his or her own life.

Excerpt from:

Psychologists Think They Found the Purpose of Depression

By Drake Baer
New York Magazine
February 9, 2017

Depression is pervasive: In 2015, about 16 million — or 6.7 percent of — American adults had a major depressive episode in the past year. Major depression takes the most years off of American lives and accounts for the most years lived with disability of any mental or behavioral disorder. It is also expensive: From 1999 to 2012, the percentage of Americans on antidepressants rose from an estimated 6.8 to 12 percent. The global depression drug market is slated to be worth over $16 billion by 2020.

The National Institute of Mental Health defines a major depressive episode as “a period of two weeks or longer during which there is either depressed mood or loss of interest or pleasure, and at least four other symptoms that reflect a change in functioning, such as problems with sleep, eating, energy, concentration, and self-image.” This falls in line with what Matthew Hutson, in a new feature for Nautilus, describes as the disease model of depression: that depression is “a breakdown, a flaw in the system, something to be remedied and moved past.” In his compelling and challenging piece, Hutson profiles several researchers who advance an argument that depression can serve a possibly positive purpose in the lens of evolution. But rather than deifying evolution and trying to scry out what it meant for us, let’s focus on what’s more immediately useful for lived human lives today: that, in some circumstances, depression may be, in the arc of a life, yielding of insights and personal meaning. All of this is in no way meant to minimize the suffering that depression can cause — but to suggest the uses that it may serve.

At the center of Hutson’s piece is Paul Andrews, an evolutionary psychologist at McMaster University in Canada. Andrews argues that depression may be “an adaptation for analyzing complex problems.” He sees it in the condition’s bouquet of symptoms, which include “anhedonia,” or an inability to feel much pleasure; people who are depressed ruminate frequently, often in spirals; and they get more REM sleep, a phase associated with memory consolidation. This reflects an evolutionary design, the argument goes, one that’s to, as Hutson summarizes, “pull us away from the normal pursuits of life and focus us on understanding or solving the one underlying problem that triggered the depressive episode.” Like, say, a “failed” relationship. The episode, then, is a sort of altered state, one different from the hum of daily life, one that’s supposed to get you to pay attention to whatever wounding led to the upset. For example, 80 percent of subjects in a 61-person study of depression found that they perceived some benefit from rumination, mostly assessing problems and preventing future mistakes….

….This framing of depression as a space for reflection is empowering, and lends a degree of agency to the person being pressed down. Like anxiety, depression might be trying to tell you something. The language of therapeutic traditions is useful: a Jungian analyst would describe depression as katabasis, an Ancient Greek word for descent. Like Orpheus heading to Hades or Luke Skywalker in the swamps of Dagobah, it’s a journey into the underworld, where the adventurer is to “go through the door … immerse himself in the wound, and exit from his old life through it,” like [sic] Robert Bly writes in Iron John. Since it is subjective, the problems and solutions will be personal — of the person and their particular psychological history — and thus demand the individualized understanding of the sufferer of depression, perhaps with the assistance of a skilled therapist. That’s another theme: While disengagement from emotionality characterizes depression and other disorders, engagement with one’s inner world looks to to be the way out. Put more poetically: You exit through the wound.

Most episodes of depression end on their own — something known as spontaneous remission,” Vanderbilt psychologist Steven Hollon tells Nautilus, noting that the depression-as-adaptation narrative may explain why. Indeed, “cognitive behavioral and problem-solving therapies may work precisely because they tap into and accelerate — in a matter of weeks — the very processes that have evolved to occur over the space of months,” he added. Katabasis leads to catharsis; not coincidentally, there’s a shared theme in the personal narratives of people who reach midlife with a sense of well-being and generativity toward others: redemption.