Exercise isn’t always the first thing that comes to mind when we’re feeling stressed or anxious. For many of us, it’s more tempting to grab a pint of ice cream and the remote control than to head to the gym. But before you open that freezer, consider this: Recent studies have found that people who exercise regularly aren’t just more physically fit than those who don’t, they’re generally happier and less stressed, too.
Exercising just 30 minutes several times a week can relieve general anxiety and stress, and can be an effective treatment for more serious conditions such as post-traumatic stress disorder and depression. A recent study conducted at the University of Colorado suggested that physical activity also can prevent stress to our immune systems, leaving us less susceptible to some bacterial and viral infections.
Perhaps most importantly, studies have shown that people who exercise have a more positive outlook on the world in general. The good news is that you don’t need to train for a marathon to brighten your perspective on life — for people new to exercise, even as little as 10 minutes a day has been shown to reduce stress and anxiety, and promote a general sense of well-being.
The Mind-Body Connection
Researchers don’t know exactly how exercise reduces stress, but they have a number of possible explanations. “More than likely, the results stem from a combination of physiological and mental factors,” says Steven Petruzzello, a professor of kinesiology and director of the exercise psychophysiology laboratory at the University of Illinois, Urbana-Champaign.
One explanation is that exercise itself is a form of stress, and forcing your body to move from its normal state of rest provokes a natural “fight or flight” response that activates endorphins — hormonelike substances in the brain, chemically similar to narcotics, that are believed to control our moods and emotions along with our responses to pain. This is a popular theory, but Petruzzello cautions that most of the studies that support it measured endorphins in the blood. Researchers still aren’t sure whether these compounds behave the same way in the nervous system.
Another possible explanation is that exercise raises body temperature. Researchers suspect this plays a role in the relaxed state of mind we experience after a workout, because warming the muscles makes them more flexible and releases tension. Based upon his research, Petruzzello speculates that exercise also increases the temperature of our brains, setting off a series of neurochemical reactions that trigger the activity of compounds such as serotonin and dopamine, two chemicals that facilitate communication between parts of the brain. Researchers believe both compounds play important roles in mood regulation and are associated with pleasurable feelings.
Petruzzello’s research indicates that physical activity also stimulates activity within parts of the brain and gives us more energy — a claim supported by several other studies in which people who exercised regularly reported having more “vitality” or “vigor.” Animal studies conducted by William Greenough, one of Petruzzello’s colleagues at the University of Illinois, showed that exercise enhanced the mental agility of chimpanzees, enabling them to master new tasks more quickly.
But there may be a much simpler explanation why exercise helps reduce stress: Fitting comfortably into our favorite pair of jeans makes us happy. While some studies have failed to find a direct correlation between improved cardiac and respiratory fitness and a positive mood, other research has shown that people who begin exercise programs, especially those who were previously sedentary, feel less tense and anxious as they lose weight.
Just as scientists are still determining exactly how exercise reduces stress, they’re also trying to figure out how much exercise we need to experience a positive change in mood. The jury is still out, but all signs indicate that a little exercise goes a long way.
“We still do not know the exact prescription,” Petruzzello says, “but studies show that even as little as six to nine minutes of exercise can reduce stress and anxiety.” In fact, longer periods of exercise also are beneficial, but too much intense exercise can actually cause stress instead of relieving it, because it overtaxes the body. When you get the right mix, Petruzzello says, you can expect the exercise “afterglow” to last about two to four hours.
Whether you’re seeking better health or stress relief, the general prescription is at least 30 minutes of exercise five times a week. You don’t need to exercise all at once — even 10 minute bouts that add up to 30 minutes over the course of the day have been proven to promote relaxation. But if your goal is weight loss, you’ll need that 30 minutes all at once: Studies have shown that a brisk 30 minute walk five times a week over a period of eight weeks promotes feelings of vigor and happiness, reduces body fat and improves cardiorespiratory health. People who exercised for shorter periods experienced the mood benefits but didn’t see changes in body size.
Aerobic activity in doses of 30 minutes, three to five times a week, also has yielded dramatic results for people suffering from clinical depression. Researchers at the University of Texas Southwestern Medical Center found that people with clinical depression could reduce their symptoms by nearly half just by adding regular aerobic exercise to their treatment. For mild or moderate cases of depression or anxiety, the researchers concluded that exercise could potentially replace medication.
You don’t necessarily need to join a gym to brighten your outlook on life. In a survey of more than 1,000 adults, researchers found that people who participated in any of 22 outdoor activities (such as cycling or climbing) were happier in seven of eight categories they measured on a “Happiness Index.” Participants who were inactive scored the lowest in five of those same eight categories.
Many activities may prove beneficial, but research suggests the most effective exercises are rhythmic activities that work the major muscle groups and are performed at moderate or low intensity — such as jogging, swimming, cycling and walking. Studies also have shown that mentally stimulating forms of exercise, such as martial arts, promote positive mood changes, especially as the participants’ skill levels improve.
But if you’re the kind of person who prefers gardening to running laps, then spending time in the garden may be your best bet. You’ll reap the greatest benefits if you exercise regularly, so choose an activity you already enjoy and find time to do it consistently.