HOW EXERCISE WORKS AS AN ANTIDEPRESSANT 

Most of us know that exercise is good for our physical health. It helps maintain strength and flexibility as we age, improves weight control, lowers blood pressure, reduces the risk of diabetes and heart disease, and improves immunity.

Few of us realize, though, that exercise is just as important for preserving mental health. For those of us who currently struggle or have struggled in the past with depression, exercise can take on a whole new role as part of our mental health treatment plan.

Exercise – as a treatment? Absolutely!

The first large scale research study on the antidepressant effects of exercise was done in the US in the 1990’s, by Dr. Jim Blumenthal. The study took 156 patients with a diagnosis of clinical depression, and assigned them randomly to treatment with either Zoloft (a common prescription antidepressant) or exercise. You might think that for an exercise regimen to be effective against depression, it would need to be very intense. Strenuous, bathed-in-sweat, “feel the pain” sessions of vigorous activity for an hour or two at a time, likely every day.

Exercise intense

Ready for some great news?

All Dr. Blumenthal had his patients do was take a brisk half-hour walk three times a week. That’s it. No marathon running sessions, no grueling make-your-neck-veins-bulge weight lifting. Just walking. (Most of the patients involved in the study were middle-aged and quite out of shape – so they likely couldn’t have completed an intense regimen anyway!)

In the study, this relatively low ”dose” of exercise was shown to be more effective than Zoloft in the longer term! The two treatments actually had about equal in effectiveness for the first several months, but by ten months into the study, the exercisers were much more likely that the medicine-takers to be depression-free. And since this first landmark study, many other clinical trials have shown exercise to be an effective treatment for depression.

If the research isn’t enough to convince you, how about the opinion of an associate professor of psychiatry at Harvard Medical School? This is what Dr. John Ratey, author of SPARK: The Revolutionary New Science of Exercise and the Brain, says about exercise:

“It is simply one of the best treatments we have for most psychiatric problems.”

Exercise is not just a helpful little adjunct, something to possibly add on to a “real” treatment program. It is a powerful treatment in and of itself. Wow!

What does exercise do in the brain that makes it so powerful?

Exercise changes the levels and activity of key brain chemicals and hormones. By doing that, it changes brain function. Think of it this way: it has the same effects as psychopharmacological medication. Really, exercise IS medicine. Except that this medicine has side effects that anyone would be happy to accept: weight loss, prevention and better management of diabetes and heart disease, and greater strength and endurance.

Let’s just look at one amazing effect of exercise in detail.

Exercise prompts the production of a compound called BDNF (brain derived neurotrophic factor). This powerful protein is a growth hormone produced by nerve cells. Dr. Ratey calls it “Miracle-Gro for the brain”, because it literally acts like fertilizer. BDNF stimulates the growth of brain cells, and increases the number of connections between them (scientists call these processes neurogenesis and neuroplasticity). These functions allow our brains to grow and change throughout our whole lives.

Depression causes levels of BDNF to plummet. With longer lasting depression some parts of the brain – for example the hippocampus, which is involved with memory – will actually start to shrink. Learning and memory will be impaired. Exercise combats this effect, by reversing the trend and actually increasing BDNF production. This revitalizes the brain in a way nothing else can.

So, would you like to use exercise to get more refreshing sleep, improve your concentration and memory, and boost your mood?

Here’s the exercise prescription:

  • Choose an aerobic activity (the aim is to do repetitive movements with large muscle groups, which increases your heart rate)
  • Do this activity for at least 30 minutes, three times a week

Hopefully this is already a lot more understandable than the hieroglyphics your doctor may scribble on a prescription pad, but let’s clarify a few points for good measure.

Common choices of aerobic activities would be walking (the absolute winner, as it is doable just about anywhere, by anyone), jogging, biking or swimming. The key thing is it has to be continuous activity – not stop and go. For exercise to be effective, your heart rate has to get up and stay up steadily for at least 30 minutes. So unfortunately, taking a leisurely walk your dog and pausing repeatedly for the “sniff and sprinkle” doesn’t count.

You may be wondering how high your heart rate really needs to be. First, I’ll address those who like numbers and technical definitions. Aerobic means that your pulse is 60 to 90% of your maximum heart rate. (Your maximum heart rate is the number 220 minus your age). Obviously, if you’re just starting out with an exercise routine, aim for the low end of the spectrum. Then as your body gets used to the activity, you can nudge the intensity higher.

For those who aren’t into numbers, graphs of target heart rates, and digital gizmos, here’s a simple way to assess your workout:  With aerobic exercise, you want to be able to speak, but feel it’s a little “choppy”. If you can speak in long sentences – or sing! – push yourself a little harder. On the other hand, if you can’t speak at all because you’re gasping for breath, tone it down.

Remember to start small, and work up gradually – especially if you haven’t done any regular exercise for a while. But hang in there, and you’ll see the benefits! At the 30 minutes, three times a week level, most people with depression start feeling better within a few weeks.

Trust me, I was a long-standing couch potato, a confirmed nerdy bookworm who was never involved with sports even as a teenager. The most physical activity I ever did regularly as a young adult was Hungarian folk dancing (and that was greatly influenced by the fact that a certain good-looking, single young man was in the dance group. He now happens to be my husband.)

Now, having found a combination of activities that I feel comfortable doing, and recognizing the powerful effects on my well-being, I make it part of my routine to have 4-5 hours of physical activity a week. It is crucial in controlling my diabetes, helping me lose weight (over 60 pounds to date), and preventing a relapse of depression.

So, anyone up for a walk?

Blessings!

 

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