Depression is a very complex emotion that is influenced by many factors.
Sometimes depression can be brought on by a serious illness in yourself or a family member. Other times, depression may be due to significant life altering events. In many cases, genetics and gene expression can play a crucial role.   While it is not thought to be possible to change your genes, it is possible to change your gene expression (they way your genes work). In addition, there are many lifestyle modifications you can make to improve your emotional state.  Today we will focus on the beneficial role of exercise in treating depression.

The number of research articles written on the causes and treatments for depression is staggering. It has been repeatedly demonstrated that people suffering from depression have altered brain chemistry and function. The ENIGMA consortium, a large multi-center collaboration of 70 institutions, has analyzed both genetic data and neuroimaging studies with regard to depression. They have established that the size of the hippocampus, the area of the brain responsible for memory and emotion, actually decreases in response to chronic depression.

So what can you do to prevent this?

Exercise!!!

An excellent article written by Lynette Craft and Frank Perna, in The Primary Care Companion – Journal of Clinical Psychiatry, published in 2004, address various theories as to why exercise helps depression.   It is highly possible that the combination of all of the theories presented below lead to the beneficial effects of exercise with regard to depression.

The first hypothesis as to why exercise benefits those with depression is termed the Thermogenic Hypothesis. The idea behind this hypothesis is that exercise raises your core body temperature and the temperature in your brain. When the temperature rises this increases the activity of certain areas of the brain thereby altering brain chemistry and improving depression.

Another theory is termed the Endorphin Hypothesis. This hypothesis asserts that exercise increases endorphin levels. Endorphins are substances what are released by the brain during exercise, and help to relieve pain and increase feelings of pleasure.   Endorphins essentially are morphine or opioid compounds produced by our bodies.   There is some criticism to this hypothesis because it is not known if these elevated levels of endorphins detected in the blood after exercise actually induce a change in brain chemistry.

Currently the Monoamine Hypothesis seems to have the most support. The basis for this hypothesis is that exercise causes an increase in the availability of neurotransmitters such as dopamine, norepinephrine and serotonin in the brain. The concentrations of these neurotransmitters are often lower in depressed people. In fact, most anti-depressant medications work by preventing breakdown of these important neurotransmitters.   Studies done in the 1970’s by RM Post and others have demonstrated an increase in these neurotransmitters both in the blood and in the urine after exercise.   Theoretically, this rise in neurotransmitters may lead to a decrease in depressive symptoms.

The Distraction Hypothesis states that intense exercise leads to distraction from worry and depressing thoughts.   In this hypothesis, exercise is likened to a meditative state and serves to provide solace and relief from feelings of despair.   These distraction activities serve as a type of coping mechanism.

Finally, there is the Self-Efficacy Hypothesis. This hypothesis asserts that by consistently participating in an exercise program, you develop a sense of confidence. This cycle becomes a self-fulfilling prophecy. Initially when you begin an exercise program, you are filled with feelings of doubt and insecurity, however as you begin to stick to the program and see benefits, you become more confident and determined to persist.   This confidence is thought to offset depressive thoughts.

Most likely all of these hypotheses are at least partially correct. So what’s the take home message?

Stick to it and continue exercising!!!  

The most common benefits of exercise include:

• Improved endurance
• Improved cardiovascular fitness
• Improved balance
• Improved strength and flexibility
• Improved body composition (increased muscle mass, decreased fat stores)
• Improved sleep
• Improved self-esteem
• Stress reduction
• Decreased depression and anxiety

The most important times to exercise are the times you don’t want to exercise. It is rare that you will leave an exercise session feeling worse then when you entered. Not every day will be the best day, but you just need to show up and give it your all. If you are on the fence about coming in, just focus all the benefits you obtain from routine exercise!