Can You Become Addicted to Exercise?

Historically, researchers have been interested in determining the minimum amount of exercise needed to be healthy. And for good reason, since most of us don't engage in enough exercise. In fact, only 20 percent of U.S. adults meet physical activity guidelines. So we often admire people who exercise a lot because we believe that they must be healthy. Not necessarily.

Have you ever noticed a very avid exerciser at your local gym -- someone who is always running on the treadmill for long lengths of time, or hovering around the weight room well after others have showered and called it a day? Perhaps you've even felt lazy and out of shape by comparison, and have admired this person's dedication and motivation. But did you ever stop to wonder whether this person's commitment to exercise might have turned into an addiction?

Recent research is beginning to shed some light on the notion that there may be a point at which too much exercise may have detrimental physical and psychological health effects and turn into an addiction. How can you tell if someone may be addicted to exercise?

Just because someone runs seven days a week for an hour each time or has been regularly attending fitness classes for several years doesn't mean he or she is addicted to exercise. In fact, there are thousands of people who can be physically active six or even seven days a week who should not and could not be classified as an exercise addict. Addiction is indicated not only by the behavior, but also by the psychological reasons underlying that behavior. If a person reports feelings of anxiety and depression when unable to exercise, spends little to no time with family or friends because of physical activity involvement, and continues to exercise despite a doctor's advice to allow an overuse injury to heal, he or she may be at high risk for exercise addiction.

[Read: 10 Signs You're Exercising Too Much .]

Just because someone runs long distances such as half marathons, marathons and even ultra-marathons does not mean that this person is addicted to exercise. It is the compulsive need and pathological motivation to exercise that distinguishes someone from a regular exerciser, to a highly committed exerciser, to an addicted exerciser.

Each of us has a unique tipping point beyond which continuing to sweat, lift, push or pull does more harm than good. People addicted to exercise continue to keep going despite injuries, mental issues, social obligations and physical exhaustion. They may even watch their careers crumble, and their family and friends drift away because exercise is their top (and sometimes only) priority. In other words, physical activity engulfs an exercise addict's personal, professional and social life, and is experienced by the addict as difficult to control or reduce in frequency -- even in the face of illness or injury.

[Read: Exercising After You've Gone Under (the Knife, That Is) .]

To determine the extent of an exercise addict's suffering, criteria have been developed. Someone may qualify as exercise addicted if at least three of the following seven criteria apply to their exercise behavior.

-- First, the exerciser needs to increase the time spent exercising or the intensity of the workout to achieve the originally desired effect (such as being in a better mood or having more energy). In other words, the amount of exercise that once sufficed no longer makes as much of a difference. This is referred to as tolerance.

-- The second criterion, withdrawal, refers to negative moods that are experienced when an addict is unable to exercise. When a person can't squeeze in his preferred running routine as planned, negative moods such as anxiety, depression and frustration often creep in. And addicts may also feel driven to exercise just to offset these negative moods.

-- The third criterion, intention effects, occurs when people exercise more than they had originally intended to. An exercise addict is unable to stick to the intended time and will often exercise much longer or with a higher intensity than originally planned. Despite intending to spend 30 minutes on the treadmill, an exercise addict may spend more than an hour running.

-- The fourth criterion is loss of control over the exercise behavior. Even with the awareness their exercise schedule is getting out of hand, exercise addicts are either unable to stop or cut back. More reps are added and more miles are run.

-- The fifth criterion, time, refers to huge amounts of time spent engaging in exercise or exercise-related activities. A large chunk of an exercise addict's time during the day is devoted to physical activity. Vacations are often fitness-oriented (such as ski and hiking trips), employment may be exercise-oriented (such as working at a gym or being a personal trainer), and reading material is often fitness-related.

-- The sixth criterion, conflict, refers to non-fitness related activities that fall by the wayside because they conflict with exercise. Time spent relaxing with friends or family is truncated to make more room for exercise. What once brought an exercise addict fulfillment may seem like a nuisance because it gets in the way of his or her workout.

-- Finally, continuance refers to continuing to exercise despite physical or psychological issues that should prevent the activity. Exercise addicts often push past pain, injury and illness to finish a workout -- even against their doctor's orders. If an exercise addict has been told they have an overuse injury, it will not stop their exercise routine. They will find another activity or push through the pain. The alternative of taking time off is not an option for an exercise addict.

It's difficult to separate healthy exercise from obsessive exercise. Meeting some of the above criteria doesn't necessarily mean you're an exercise addict. A lot of people with a healthy attitude toward exercise choose to become personal trainers, work at a gym and run marathons and even ultra-marathons. It's when exercise becomes all consuming -- when you start losing friends, forgoing social activities or reneging work opportunities -- that your workout schedule becomes cause for concern. For most of us, exercise is great for the body, soul and mind. But for a limited number (about 0.4 percent of the population), it can turn into an addiction.

[Read: 4 Exercises Trainers Hate .]

Heather A. Hausenblas, PhD, is a faculty member in the College of Health Sciences at Jacksonville University. She is an internationally renowned physical activity and healthy aging expert, an award-winning researcher, and an author. She is a regular contributor to both local and national media outlets. Her research focuses on the psychological effects of health behaviors, in particular physical activity, across the lifespan. Dr. Hausenblas is the co-author of five scientific books, and she has published more than 90 scientific journal articles. She is a mom to three young boys, and she enjoys exercising outdoors, spending time with family and friends, and coaching and watching her sons play sports. She resides in Jacksonville, Florida with her husband and boys.