Mood Enhancement

Poets and musicians have it all wrong. It’s a broken brain, not the heart that makes us suffer so. "You’re a brain breaker, dream maker, love taker, don’t you mess around with me..." (extra credit for knowing and singing this tune!). It has been estimated that more than one in five adults suffers from a major depressive disorder at some point in their lives. Depression has many possible contributors including faulty mood regulation by the brain, genetic vulnerability, unhelpful patterns of cognitive appraisal, and stressful life events (especially how a person interprets these events). It is believed that several of these contributors interact to bring on depression. 

Well-being, mood, it’s all in the brain, and the hippocampus is an important player. A 1996 study by Yvette Sheline of Washington University found the hippocampus of depressed women to be 15% smaller than their nondepressed counterparts and the degree of shrinkage was directly related to the length of the depression (serendip.brynmawr.edu, also Ratey, Spark, loc 1817). Chronic depression may also cause structural damage in other areas of the brain. MRI scans of depressed patients have shown gray matter in the cortex physically shrunken. This is the area that directs complex functions such as attention, emotions, memory, and consciousness. (Ratey, Spark, loc 1806). 

“Depression is a bona fide brain shrinker that has been shown to reduce the size of the hippocampus and lead to a reduction in cognitive performance. Depressed patients often report memory problems, difficulty focusing and sustaining attention, and low motivation. Fortunately, treatment of depression has been shown to reverse hippocampal shrinkage in just six months.” (Majid Fotuhi, Boost Your Brain, pg 53).

Depression can be thought of an an erosion of connections, in the brain and in life. (Ratey, Spark, loc 1622). And if depression is the breakdown of the brain’s connectivity, that is good news for the value of exercise because it reestablishes those connections. 

Lower levels of BDNF are associated with depression. One study of thirty depressed patients showed that every one of them had lower than normal BDNF levels. Exercise has been found to boost BDNF as least as much as antidepressants. (Ratey, Spark, loc 1860, pg 131). 

The array of antidepressant drugs target three neurotransmitters: norepinephrine, dopamine, and serotonin in different combinations. When a person is diagnosed with depression, it’s a matter of trial and error to find the right drug to relieve it. There’s no blood test for depression, and no test to tell which neurotransmitter if any is at fault. Many researchers have questioned the efficacy and clinical significance of antidepressant medications, especially for mild and moderate cases (for example: https://www.madinamerica.com/2017/02/new-data-showslack-efficacy-antidepressants/). However, exercise appears to increase and balance all of the neurotransmitters targeted by antidepressants. It elevates levels of norepinephrine, waking up the brain and improving self-esteem. It boosts dopamine which affects motivation and attention. And it regulates serotonin which is important for impulse control and feelings of serenity and hopefulness. (Ratey, Spark, loc 1719). In Britain, doctors are writing prescriptions for exercise as a first line treatment for depression, and doctors in the United States are beginning to catch on. 

But what if you don’t have the full line of symptoms for a clinical diagnosis of depression but just feel down?  What if you just feel less than well or want to feel better than okay? Aerobic exercise has a positive impact on a range of symptoms and behaviors contributing to well-being, even when they are mild. If you’re a data person, we’ve got lots of this for you to chew on. A huge study of 19,288 Dutch twins and their families showed exercisers to be less anxious, less depressed, less neurotic and more socially outgoing.  A Finnish Study in 1999 showed that those who exercise at least two to three times a week experience significantly less depression, anger, stress, and ‘cynical distrust’. (Ratey, Spark, loc 1675). An Australian study found after two months of exercise participants not only reported significant decreases in emotional stress, but they smoked less, drank less alcohol and caffeine, ate healthier, lost their tempers less often, did more household chores, kept more commitments, spent less money, and improved their study habits. (Oaten M1, Cheng K., Longitudinal gains in self-regulation from regular physical exercise, Br J Health Psychol. 2006 Nov;11(Pt 4):717-33.)

There are piles of studies finding exercise to relieve symptoms of depression and improve overall mood, but here’s one in particular we’d like you to pay attention to. A landmark investigation called “SMILE” (Standard Medical Intervention versus Long-term Exercise) is one of many eye-opening studies that supports exercise as an important mood-boosting intervention. In 2000 researchers at Duke University found exercise to be at least as effective as Zoloft for relieving depression. One hundred fifty-six depressed patients were randomly put into one of three groups: 1) antidepressant medication treatment, 2) exercise, or 3) both antidepressant and exercise. The exercisers worked at 70-85% of heart rate reserve three times a week. At the end of four months all groups showed the same decrease in depressive symptoms, suggesting that exercise and antidepressant treatments were equally effective (in the short term). The really interesting finding came from evaluating relapse rates 10 months later. At follow-up, 38% of the antidepressant group had relapsed into depression, and a similar 31% of the combined antidepressant/exercise group had relapsed as well. But the relapse rate for the exercise-only group was just 9%! (October 2000 Duke University New York Times. Exercise is better than Zoloft at treating depression). Let that sink in for a moment; how would you explain these results? 

It’s fascinating to consider why the exercise-only group would have significantly lower relapse rates than those who got medication and exercised. Further research is needed to better understand this finding, but it may have to do with a person’s attributions for improvement; that is, what they thought about why they improved. For example, some participants in the combined treatment may have believed that the medication was responsible for their improvement (not their own efforts at exercising), leaving them more vulnerable to relapse in the long-term. In contrast, those in the exercise-only group could attribute their improvement to their own efforts, increasing their sense of self-efficacy, which in turn leads to other healthy behaviors and thought patterns. Whatever the underlying mechanisms are for mood-enhancement, exercise is clearly a good thing for body, mood, and mind.    

Positive psychology author Tal Ben Shahar explains the relation between mood and exercise in a different way than you’ve likely heard before. Considering our evolutionary context in which we often had to RUN to catch our lunch, or RUN to avoid being lunch, an active lifestyle is the default condition for human physical and mental health. As a result, he explains that rather than thinking about exercise being like taking an antidepressant, it may be more accurate to say that not exercising is like taking a depressant! Who would do that, right? (Well, besides millions of us modern humans).    

Whether or not you’ve skipped through all the brainy science-speak to this point, watch this video now for an engaging summary of these and other points that will increase your motivation to follow through with your exercise intentions: