How many studies does it take to convince you that moderate exercise will make you happier? If you need one more reason to start being more physically active, professors from the University of Toronto have compiled and analyzed over 26 years’ worth of scientific research which concludes that even moderate levels of physical activity—like walking for 20-30 minutes a day—can ward off depression in people of all ages.
University of Toronto PhD candidate George Mammen co-authored a review of 25 different research articles, which show that moderate exercise can prevent episodes of depression in the long term. The compilation of research is published in the October issue of the American Journal of Preventive Medicine.
All Animals Seek Pleasure and Avoid Pain
The premise of The Athlete’s Way: Sweat and the Biology of Bliss is that exercise makes people feel good. If exercise is something you associate with being happy and feeling good you will be more likely to seek it out and make physical activity a part of your daily routine. Over the long run, people don't stick to a workout regimen because of superhuman willpower—they stick with it because they realize how much better they feel after a workout. Sweat = Bliss. This is a universal neurobiological fact. Breaking a sweat is a hedonic pursuit.
Our bodies and minds are hardwired to feel good when we work out. This is a generous biological design but also necessary for our survival. Everything humans need to survive—food, water, sleep, social connections, sexual contact, breathing deeply, and physically working our bodies (sweating)—are all designed to release a cascade of rewarding neurochemicals that send us coming back for more.
On the flip side, not being physically active can cause your body and mind to shortcircuit. This is one of the biggest ‘future shocks’ of living in a digital age. Humans are not biologically wired to be isolated in cubicles or sedentary behind computer screens.
Exercise Is an Elixir for Depression
Given the high prevalence of depression in the modern world, more research is needed to identify all the factors that cause and might prevent depression. Increasingly, physical activity is being recognized as an effective tool for treating and preventing depression.
The University of Toronto review examined whether physical activity is protective against the onset of depression by compiling massive amounts of previous data. Their comprehensive search was conducted up until December 2012 in the following databases: MEDLINE, Embase, PubMed, PsycINFO, SPORTDiscus, and Cochrane Database of Systematic Reviews.
Articles were chosen for the review if the study used a prospective-based, longitudinal design and examined relationships between physical activity and depression over at least two time intervals. A formal quality assessment for each study also was conducted independently by the reviewers.
The initial search yielded a total of 6,363 citations. After a thorough selection process, 30 studies were included for analyses. Among these, 25 studies demonstrated that baseline physical activity reduced the risk of subsequent depression.
The majority of these studies were of high methodologic quality and provide consistent evidence that physical activity boosts happiness and prevents future depression. There is growing evidence that even very moderate levels of physical activity (e.g. walking 20-30 minutes a day, which adds up to just over two hours per week) can prevent future depression.
Conclusion: Moderate Exercise Could Replace Costly Medications with Side Effects
From a public health perspective, promoting physical activity is a valuable mental health strategy. Promoting exercise could reduce the risk of Americans developing depression en masse and reduce depression's personal, social, and economic repercussions.
George Mammen’s findings come at a time when mental health experts are looking for ways to treat depression without costly prescription medication. He says, “We need a prevention strategy now more than ever. Our health system is taxed. We need to shift focus and look for ways to fend off depression from the start.”
There are many factors that influence a person’s odds of experiencing depression, including one’s genes. There are always going to be certain individuals and situations where medication may be a necessary ingredient for combatting depression.
Mammen concludes that the scope of research over the past 26 years confirms that regardless of individual predispositions, that moderate exercise not only treats, but can prevent depression. “It’s definitely worth taking note that if you’re currently active, you should sustain it. If you’re not physically active, you should initiate the habit. This review shows promising evidence that the impact of being active goes far beyond the physical.”
If you'd like to read more on this topic please check out my Psychology Today blogs: "The Neurochemicals of Happiness", "Self-Reliance in the Age of Obamacare","Four Lifestyle Choices That Will Keep You Young", "Exercising at a 'Conversational Pace' Is Good for Your Brain", "Scientists Discover Why Exercise Makes You Smarter" and "4 Ways to Create Healthier Behavior."