Depression: we’ve all heard of it. It’s a clinical mental health concern that manifests as a depressed mood or loss of interest or pleasure in daily activities for at least 2 weeks. Other symptoms include disturbed sleep, suicidal thoughts, and reduced concentration. The World Health Organization predicts that depression will become the leading cause of death and disability by 2030. So what can we do to treat and prevent depression?

Substantial research has shown that physical activity levels are associated with the prevalence of depressive symptoms in adults of all ages. Further, studies have shown exercise interventions to be successful in both preventing and treating depression! Could it be that simple? Let’s look at the data…

STATS:

• The U.S. National Comorbidity Study (Buckworth et al., 2013) conducted a nationally representative survey and found that those who participate in regular physical activity had 25% lower odds of being diagnosed with depression. In fact, for each categorical increase in physical activity (never, rarely, occasionally, regularly), there was a corresponding decrease in the prevalence of mood disorders overall.
• The CARDIA study controlled for variables like age, education, BMI, smoking, and alcohol use and found that for each depressive episode, individuals averaged 28 fewer METs of physical activity per year.

PREVENTION:

Studies have tracked individuals over time to establish the temporal relationship between the onset of a change in exercise and the onset of depressive symptoms.

• Out of 30 prospective studies from 12 countries, nearly all showed that depressive symptoms decreased with increases in physical activity, showing that exercise does indeed help prevent depressive symptoms (Buckworth et al., 2013).
  
  The case for using physical activity to prevent depression is supported if the data shows a “dose-response” relationship. This means that a greater “dose” of physical activity should correspond with a greater decrease in odds of developing depression. Less active people should have lower odds than nonactive individuals, but super active people should have even lower odds than moderately active people, and so on.
   
• The Australian Longitudinal Study on Women’s Health looked at over 9000 women and found that you get the largest bang for your buck when increasing your activity level from “no exercise” to “very little exercise.”
• Further, they found that the women who were inactive at first and became moderately active by 3 years later reduced their odds of developing depression by 25%. Those who became highly active cut their odds in half during the 3-year span.

These results suggest that the exercise need not be highly intense in order to benefit.

• Another study (Bernard et al., 2014) targeted postmenopausal women who were at risk for depression due to being inactive. These women completed a six-month, three-session per week, moderate-intensity walking intervention. They found that the simple, widely accessible walking intervention was successful in reducing depression in their sample.

TREATMENT:

• A study by Blumenthal et al. (2007) found that exercise interventions were AS SUCCESSFUL as the medication at treating depression!
• Dunn et al. (2005) found that individuals with depression who burned 250-400 kcal/day during exercise 5x/week improved symptoms by twice that of any other dose/frequency combination.
• Singh (2005) found similar results in their study of resistance training rather than aerobic training, with higher-intensity exercise producing twice the efficacy of low-intensity training.

According to these studies, any kind of exercise is better than none, and if you’re completely inactive, you’ll see a huge benefit in depressive symptoms by just becoming minimally active.

This research is strong enough that one day, doctors could be prescribing exercise instead of traditional pharmacological treatments.

How active is “minimally active?”

The ACSM recommends 30 minutes of moderate-to-vigorous physical activity per day. This doesn’t have to be RUNNING or SWIMMING, but can simply be WALKING. Is there a trail or sidewalk near your home or workplace you could stroll down during your lunch break or while you wait for rush hour to end? Whatever it is, you’re best off picking something that is fun for you. Hate running? Don’t do it! We know that individuals who don’t enjoy an activity are far less likely to continue doing it. In the long run, it’s the habits that matter, so go ahead and start! See how much you won’t miss by walking 30 min/day! You can improve your physical and mental health greatly in the process!

…Until next time!

Lauren Becker
Carolina Performance Intern
Master’s Student in Kinesiology at UNC-Greensboro
Correspondence can be directed to: lvbecker@uncg.edu