When you're feeling blue, often the last thing you feel like doing is working out. But try to fight the urge to curl up on the couch! You may just find that a bit of exercise can lift your mood and leave you feeling refreshed.

Why is this? It has everything to do with the connection between exercise and endorphins, and other related brain chemicals.

What Are Endorphins?
Endorphins are the "feel-good" chemicals--or neurotransmitters in the brain--that give you a boost when you are working out. According to the Mayo Clinic, endorphins are natural painkillers that lead to a greater sense of well-being. The release of endorphins is sometimes referred to as a "runner's high." However, many other types of physical activity besides running have been linked to this natural process.

What's the Connection Between Exercise and Endorphins?
A number of studies have shown that regular aerobic exercise may have a mood boosting effect. For example, Psychology Today reports that researchers at Duke University found that moderate exercise was as effective at treating depression as an antidepressant medication. These findings may be explained by the relationship between exercise and endorphins. Dr. Gary Small, a professor of psychiatry at UCLA, actually describes endorphins as "the body's very own natural antidepressant."

However, according to research reported by NBC News, endorphins aren't the only force behind the mood-boosting benefits of exercise. Recent studies suggest exercise also boosts other "feel-good" brain chemicals, including dopamine, serotonin, and norepinephrine. These natural substances, produced by your body when you work out, may minimize feelings of discomfort during exercise. They may even be associated with feelings of euphoria.

How Much Should You Exercise to Feel the Effects?
The euphoria some people report feeling with exercise is not well understood. Researchers interviewed by NBC News have found variation in the amount and intensity of exercise required to bring on a "runner's high."

Some people require more intense exertion to feel the positive mood-boosting effects, such as running or biking long distances. Others seem to experience the same effects from shorter and less intense workouts--for example, a hike or a game of tennis.

NBC's report emphasizes that even with longer exercise efforts, there is no guarantee that you will feel the effects. Nevertheless, some studies have suggested that just a 30-minute workout appears to raise the levels of chemicals in the brain that improve mood. This can help to ease tension, depression, and anger.

HealthAhead Hint: Get Healthy, Get Happier
It's uncertain exactly how much you need to exercise to experience a sense of "euphoria." But, one thing is clear: Exercise may help you to feel better. According to the Mayo Clinic, no matter your athletic ability, age, or weight, aerobic exercise offers a number of health benefits, in addition to mood-boosting, including weight loss, increasing your stamina, strengthening your immune system, and increasing your longevity. Regular exercise has also been linked with improved mental health as you age. But don't just take our word for it--if you want to get healthy and happy, then get moving.