Can Exercise Really Reduce Symptoms of Depression in Teens?

The short answer: yes.

Over the past twenty years, our awareness of the benefits of exercise has increased dramatically. Of course, before the recent revolution in self-care, mindfulness, and the scores of peer-reviewed scientific studies documenting the benefits of exercise, we knew that exercise was good for you.

But we never knew exactly how good it was, on how many levels it helps, and how simple it is to start a routine that yields all the benefits the experts on physical, psychological, emotional, and social health champion every day in the media, blogs, marketing pitches, and social media posts.

Prior to the 21^st century, most of us understood that exercise makes your body strong and resilient. It helps prevent disease, improves mood, and keeps our bodies functioning as we age. And most had an idea about the stress relieving aspects of exercise. Because on a very basic, human level, working hard, working up a sweat, and pushing our physical limits has a way of getting us out of our heads for a short time – and we almost always feel better, and less stressed – after a nice workout or an afternoon of physical activity.

In 2008, the Centers for Disease Control (CDC) released their “Physical Activity Guidelines for Americans,” which defined the far-reaching benefits of exercise for everyone, and included scientific research to validate their claims and recommendations. We’ll get to what they recommend for teens later in this article. First, we want to review the overall benefits of exercise for the mind and body. Next, we’ll introduce the results of a recent, large-scale, meta-analysis on the benefits of exercise in residential treatment for adolescent depression. Finally, we’ll end with the CDC guidelines on physical activity for youth and teens.

Let’s start by reviewing the overall benefits of exercise.

The Big Picture: How Exercise Helps

The 2008 guidelines informed the public of important facts. Some were known to many, but – because of the trends in the data – it was clear that many Americans needed to know more about the importance of regular exercise and activity. The authors of the 2008 report went emphasized that exercise and activity helps:

• Prevent disease
• Reduce risk of developing or dying from:
  • Heart disease
  • Type II diabetes
  • Hypertension
  • Colon cancer
• Reduce symptoms of anxiety and depression
• The development and maintenance of healthier bones, muscles, and joints
• Control weight
• Older adults maintain the ability to live independently
• Older adults prevent falling and fractures

Alongside these observations, the guidelines made simple and clear recommendations on types of exercise that yield the most benefit, and the number of hours per week people should spend in physical activity to maximize the positive outcomes of exercise. The new guidelines – Physical Activity Guidelines for Americans, 2^nd Edition – reminds everyone that everything in the 2008 publication is still valid, and includes new research on how exercise helps specific people and can reduce or prevent specific diseases and medical conditions.

Here’s the new information published in the 2019 CDC guidelines.

CDC 2019: Recently Identified Benefits of Exercise

Regular exercise and physical activity can:

1. Improve bone health and weight status for children ages 3 through 5 years.
2. Improve cognitive function for youth ages 6 to 13 years.
3. Reduce risk of cancer at a greater number of sites than previously known.
4. Improve brain health, including improved cognitive function, better sleep, and quality of life.
5. Reduce risk of excessive weight gain, gestational diabetes, and postpartum depression for pregnant women.
6. Reduce risk of all-cause and disease-specific mortality, improved physical function, and improved quality of life for people with various chronic medical conditions.

That’s a good summary of what we know about the benefits of exercise. There’s more detail, of course, particularly about the neurochemical benefits – i.e. the benefits for brain health – of exercise. Data shows exercise can increase hormones that reduce stress, reduce hormones that increase stress, increase hormones that reduce depression, and improve overall brain function.

All that is preamble to the main topic of this article: the effect of exercise on teen mental health and the treatment of teen depression. We know exercise improves everything we listed above, which makes it a logical choice as a complementary treatment for depression.

Now let’s see what the evidence says.

The Role of Exercise in Depression Treatment for Teens: New Study

A meta-analysis published in 2020 called “Physical Exercise in the Treatment of Adolescents with Depression” offers the only comprehensive review of the effect of exercise in clinical depression treatment programs for teenagers. As a reminder, a meta-analysis is a type of study that takes data from all available legitimate research published to date, applies advanced statistical techniques to examine the data, and summarizes the trends – based on solid scientific evidence and statistical analysis – on that specific topic.

In other words, in a meta-analysis, researchers look at everything they can find in order to determine the current state of knowledge on the subject of choice.

The meta-analysis we discuss today contained data from nine studies that included a total of 431 teenagers diagnosed with major depressive disorder. Researchers narrowed the results to nine after an initial search showed 25 articles that met primary criteria. They removed those with incomplete data, a poor design, or other problems.

To measure the effect of exercise on depression, they used the Children’s Depression Inventory and the Beck Depression Inventory. To normalize the results across the types of exercise used to treat teenagers for depression, researchers measure four factors:

1. Intensity

Researchers noted whether the activity was low, moderate, or vigorous.

2. Type

Researchers noted whether the activity was utilized as part of a game/sport, or standalone. For instance, whether intense activity occurred during a basketball game or during sets of pushups, squats, and sit-ups.

3. Context

Researchers determined if the exercise component of treatment was the only treatment used, or if they also participated in psychotherapy or mental health counseling.

4. Time

Researchers identified the duration of workout sessions, the number of sessions per week, the number of weeks, and the total extent of physical activity. They measured total extent in this manner: total activity = [number of weeks] x [number of sessions per week] x [minutes per session].

Now lets’ take a look at what the researchers found when they crunched the numbers from the nine studies that met their criteria for review.

The Role of Exercise in Depression Treatment for Teens: The Data

The first thing about the data we’ll mention is the completion rate. Across studies:

• 97% of the teen participants completed the exercise components of their depression treatment
• 89% of the control group participants completed their depression treatment.

We offer that information not to point out that the exercise groups completed treatment at significantly different rates than the control group – there’s no significant difference there – but to point out that teens readily accept and participate in this type of therapy. To the simple question “is this approach appropriate for teens?” the answer is an equally simple “yes.”

Now let’s look at the primary research question, “What effect does exercise have on depressive symptoms?” in terms of the four metrics we list above: intensity, type, context, and time.

1. Intensity

• Compared to control groups:
  • Low intensity exercise had no effect on depressive symptoms
  • Moderate intensity exercise had a large, significant effect on depressive symptoms
  • Vigorous intensity exercise had a moderate, significant effect on depressive symptoms

2. Type

• Compared to controls groups:
  • There was no difference in reduction of depressive symptoms between teens who participated in game-based exercise vs. teens who participated in standard physical activity.

3. Context

• Compared to control groups:
  • Teen who participated in psychotherapy + exercise reported greater reduction in depressive symptoms than teens who participated in psychotherapy only, but the effect was small.
  • Teens who participated in exercise therapy but no psychotherapy reported a significant reduction in depressive symptoms.

4. Time

• Compared to control groups:
  • The number of weeks, number of sessions per week, and minutes per session did not affect the reduction in depressive symptoms
    • All groups that participated in moderate or vigorous intensity exercise reported reduced symptoms regardless of time differences between groups
  • The study with the shortest reported time followed this schedule:
    • Two sessions per week
    • Twenty minutes per session
    • 6 weeks total duration

Using the information from that last set of bullet points on “Time,” researchers identified “twenty minutes, twice a week, for six weeks,” as the minimum time required for adolescents in treatment for depression to experience reduced depressive symptoms with exercise therapy. That’s important information, because it means exercise is a time-efficient approach to depression treatment.

The Exercise Effect: Long Duration

There’s one last thing to discuss about the data in this meta-analysis: the durability of the antidepressant effect of exercise. While only one of the nine studies collected data after the end of the experimental period and beyond, what they found was surprising:

• After the end of the three-month experimental period, 100% of the exercise group showed remission of depressive symptoms
• At 5 months, 88% of the exercise groups showed remission of depressive symptoms
• At 6 months, 86% of the exercise groups showed remission of depressive symptoms

That’s not only surprising, it’s also impressive. These results speak directly to our inclusion of exercise into our residential treatment programs for adolescent depression. We take the time and energy to make exercise part of the daily routine, and by the time a teen steps down out of one of our residential programs, exercise is a habit that most of them look forward to. These results show that habit works in exactly the way we want it to: it keeps our teens strong and physically healthy while simultaneously leading to a decrease in depressive symptoms.

Not to trivialize or oversimplify depression treatment for teens, but we call that a win-win.

Now let’s see what the CDC says about how much exercise a teen should get every day.

Exercise and Teens: How Much and What Kind?

To relieve depressive symptoms, the authors of the study we cite above conclude teens need at least 20 minutes of moderate or vigorous exercise, two times a week, for at least six weeks. We’ll compare that to what’s in the CDC guidelines.

CDC 2019: Exercise Guidelines for Adolescents

To achieve the maximum benefits of exercise and activity:

• Teens should engage 60 minutes of moderate-to-vigorous physical activity every day.
• A mix of aerobic, muscle-strengthening, and bone-strengthening activities is ideal:
  1. Aerobic: Adolescents should include engage in moderate aerobic activity every day, and vigorous-intensity aerobic activity at least 3 days a week.
  2. Muscle-strengthening: Adolescents should engage in strength-building activities 3 days a week.
  3. Bone-strengthening: Adolescents should engage bone-strengthening physical activities at least 3 days a week.

That’s far more than needed to reduce symptoms of depression, according to the study we discuss above – but that’s good news. It means the CDC guidelines can yield benefits for teen’s physical and mental health. In addition, the CDC advises adults to encourage teen to participate in physical activities and provide opportunities to do engage in vigorous activity whenever possible.

For parents who’ve read this far and still aren’t quite sure how to translate everything we’ve said so far to their teen’s daily life – don’t worry. We’ll tell you what to do, and how.

Specifics: What Teens Can Do to Meet Exercise Requirements and Reduce Depressive Symptoms

Here are examples of the types of activities teens should engage in as often as possible:

Moderate aerobic exercise, such as:

• Fast or brisk walking
• Cycling at an easy pace
• Kayaking, hiking, and swimming
• Games like baseball and softball
• Housework and yardwork

Vigorous aerobic exercise, such as:

• Running
• Cycling at a quick pace
• Swimming at a quick pace
• Jumping rope
• Cross-country skiing
• Sports that involve running and jumping, such as soccer, basketball, and tennis
• Martial arts

Muscle-strengthening exercise, such as:

• Body weight exercises like as pushups or pullups
• Resistance exercises using weight machines, barbells, or handheld weights such as free weights or kettlebells
• Yoga

Bone-strengthening exercise, such as:

• Running
• Martial arts
• Any activity/sport that include running and jumping

For teens who aren’t used to exercising and don’t meet the CDC guidelines, we advise parents to start them with the 20 minutes a day, two times a week minimum advised by the authors of the study we discuss above. To get them up to the level the CDC endorses – which is entirely reasonable and possible – we agree with the CDC’s three step approach:

1. Replace idle time with active time.

Teens can walk or ride a bike when they go to school, to see friends, or to the store for an errand.

2. Start easy, no pressure, and build up slowly.

Begin with low- or moderate activity, and gradually build up the intensity and duration over several weeks.

3. Variety and fun.

To get a teen interested in exercise, pique their interest in exercise. Yes, that’s redundant, but it’s true: if a teen is not interested by themselves, parents need to use what they know about their teen and leverage that to get them to exercise. It’s different for everyone, but one rule of thumb that works is to find something simple, and stick with it. Find the right thing might take time, but it will be well worth the effort.

In closing, we want to stress the importance of this three-step approach, especially for teens who are new to exercising. Expecting them to suddenly act like they joined the Marines is unrealistic: it’s unlikely a previously sedentary teen will get up at 5am every morning for a 5-mile run, a hundred pushups and a hundred situps. It’s more likely that finding a group activity – whether it’s a sport, an aerobics class, or a martial art – that’s fun and engaging will get the ball rolling.

For parent of teens who are on the verge of discharging from a residential treatment program for depression, encourage that teen to keep up with the good exercise habits they learned during treatment: they’ll last a lifetime. And, as the evidence shows, they improve physical health, brain health, and reduce the symptoms of depression.

What could be better?