Exercise PREVENTS Depression

This certainly is not the first time I have discussed physical activity and mental health.  As the days continue to get shorter over the next few weeks, the topic of depression is very timely.  During the winter months, it is not uncommon for many people to experience Seasonal Affective Disorder.  While we all deal with things in different ways, there is no better way for me to cope with short, gloomy days than by exercising.

Recently, an article published in the American Journal of Preventative Medicine titled “Physical Activity and the Prevention of Depression: A Systematic Review of Prospective Studies” set out to determine whether or not physical activity may do more than just help manage depression.  It was a comprehensive review, which began with over 6,000 citations.  It entailed a very thorough process of reviewing those citations for criteria of inclusion:

1. The study had to have a prospective-based, longitudinal design.
2. The study had to examine relationships between physical activity and depression over at least two time intervals.
3. The study had to identify physical activity as the exposure variable and depression as the outcome variable.
4. The study had to use depression threshold scores on self-report scales or direct measures from medical personnel/records.

After this process, 30 studies were left for analysis.  They were all conducted in non-clinical settings and included individuals aged 11-100. Fourteen were conducted in North America and thirteen were conducted in Europe.  Follow-up measurement intervals ranged anywhere from 1 year to 27 years, but only one of them used objectively measured physical activity (via ergometer).  There were a few different ways that “depression” was measured including the use of results from The Center for Epidemiological Studies Depression Scale (CESD), physician diagnosis, use of medication, and hospital discharge records.

Results revealed many interesting findings including:

• Twenty five of the thirty studies found a significant, inverse relationship between baseline physical activity and follow-up depression.  Four of those studies found that women who participated in physical activity were less likely to report depression.
• Seven studies measured physical activity in terms of the minutes of exercise each week.
• Two of the studies found that as little as 10-29 minutes of physical activity was preventative in the onset of depression.  In addition, results of these studies indicated that higher levels of daily physical activity were significantly associated with decreased risk of developing depression.
• Eleven of the thirty studies in this review provided information regarding the change in physical activity levels over time, and it’s association with depression.  Nine of them concluded that reducing physical activity over time increases the risk of developing depression.

I can’t say any of these findings are a surprise to me.  What’s important is how we can practically use this information. So, as we promote the benefits of physical activity and the many diseases and conditions it can help prevent, we must not forget to explain the mental health benefits as well.

Other related pieces:
Turn the Cortisol Faucet Off
Your Brain on Exercise

Source Article:  Mammen, G. & Faulkner, G.  Physical Activity and the Prevention of Depression: A Systematic Review of Prospective Studies.  American Journal of Preventative Medicine. 2013; 45(5): 649-657.