When a friend of Erin Jeffery’s suggested she join her touch-football team a decade ago, the Burnaby marketing director and mom laughed. Although she had never caught a football in her life, she tried it as a lark. She was hooked and has played ever since.

“I just went, ‘Wow, I love this,’” Jeffery says in a phone interview. “It’s a great sport. It gets me moving quickly; it’s exceptional exercise. It’s a welcoming group and a phenomenal community, and I love the fact I’m outside.

“It’s my sanity,” Jeffery adds. “I can forget about everything. I get on the field and I can’t think about things like getting older or else I’m going to get a ball in my face.”

Jeffery has hit on an undeniable truth about physical activity: whether it’s attending football practice (which, in Jeffery’s case with the B.C. Touch Football League, includes sprint drills and running patterns), riding your bike to work, going to the gym, or hiking trails, regular exercise does wonders for your mental health.

In fact, research increasingly backs up the link between movement and emotional well-being.

According to Boston University psychology professor Michael W. Otto and Jasper A. J. Smits, associate professor of psychology at Dallas’s Southern Methodist University, one reason exercise positively affects mental wellness is that it increases the production of serotonin. Low levels of this neurotransmitter have been linked to depression, they write in their recent book Exercise for Mood and Anxiety: Proven Strategies for Overcoming Depression and Enhancing Well-Being.

Then there is the theory that exercise “whips your body into better shape” to handle stressors, they contend. Exercise in itself is a stressor, forcing the body to adapt to the demands placed on it, and this kind of regular stress may help you be physiologically better at handling stress in general.

In their book, the two refer to several long-term, large-scale studies supporting the positive effects of exercise on mood.

A 2010 meta-analysis of 70 studies on the subject published in Annals of Behavioral Medicine, for instance, found that adults who reported sad or depressed moods—but not at levels that were considered psychiatric disorders—reported meaningful improvements in their mood as they started doing regular exercise.

A 2007 Psychological Medicine study of adolescents found that 16 percent of those who weren’t physically active developed an anxiety disorder over a four-year period compared to half that rate among those who exercised regularly.

Another study, from 2000 and published in Preventive Medicine, found that exercise is linked to less anger and “cynical distrust” as well as stronger feelings of social integration.

Perhaps the most convincing argument in favour of regular exercise for mood is also the simplest: unlike the goal of losing weight, the benefits of physical activity on a person’s mental state are almost immediate, Otto and Smits say. About 20 minutes into a workout, you start feeling better; that effect can last hours or even into the next day.

The authors don’t discount the role that medication and talk therapy can play in the treatment of conditions like depression and anxiety, and they emphasize that suicidal thoughts need immediate treatment. However, they argue that in many cases, exercise can function as the body’s own natural antidepressant.

Exercise is one component of the Canadian Mental Health Association B.C. branch’s Bounce Back: Reclaim Your Health program. Funded by the provincial Ministry of Health, the free program is geared to people with milder mental-health problems and helps them recognize and deal with signs of stress, low mood, and worry.

Some of the coping strategies are delivered through workbook materials and telephone coaching, with one being centred on using exercise to improve how you feel.

“Planned exercise has been shown to boost mood, reduce tension and anxiety, and improve self esteem,” Lynn Spence, CMHA B.C. division associate executive director, tells the Georgia Straight. “Additional benefits include fun, social contact, structure provided in the day, plus wider long-term physical health benefits.”

It can be hard to head out for a jog or an aerobics class when you’re feeling blue, so Spence advises setting achievable goals.

“People can start with a realistic plan, choosing exercise that they used to enjoy and scheduling the activity into their day, taking small steps towards more activity,” she says. “They might pick a physical activity that can be done in just five or 10 minutes.…They might choose to do the activity with someone else, increasing the likelihood of following through. Resulting benefits from exercise can facilitate motivation for action in other areas that are contributing factors to low mood.

“Our thinking, behaviour, relationships, life situation, and body all affect each other,” Spence adds. “A change in one can lead to change in others.”

Psychologists Otto and Smits admit that sometimes even they find it tough to get off the couch and exercise. In their clinical practice, they’ve heard every excuse when it comes to avoiding physical activity: feeling too busy, tired, depressed, or unmotivated. They offer dozens of practical strategies to put intentions into action, such as bringing an audio book to reward yourself after the fact.

Exercise, they maintain, is your chance to approach the world with “appropriate selfishness—doing what you need to do to feel better today”.

“Keep this in mind as you think about your next workout,” they write. “You are doing it to feel less stressed, less down, and more relaxed. You are doing it for the sense of energy it provides and for the sense of being in tune with your body.…The key is getting out there and making your exercise a regular part of your life.”