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What is the relationship between exercise and anorexia nervosa?
27 April 2011
Exercise is strongly correlated with anorexia nervosa (AN). Whether the behavior serves as a trigger to, a symptom of or a treatment to the disorder, the two are closely connected. Exercise relates to weight, body image and endorphins, which are also dealt with in AN. Three research studies discuss the relationship between exercise and AN. It appears that it is not the physical action of exercise that influences AN but rather the mindset about it.
Exercise as a Trigger
Often exercise is a cause of anorexia. More specifically, it is usually an excessive amount of exercise. Excessive exercise and AN are both linked to obsessionalism, perfectionism, physical discomfort and weak socialization. (Katz, 2004). Maybe a person begins to run five days a week and sees the positive results in their leaner body. That person may be led to exercise more and more until it becomes psychological that they have to run or else they will become fat. This could then translate into anorexia by the person thinking eating has to be compensated for by exercise. So, even though the person did not originally have AN and was just running to stay healthy, pleasing results triggered a distortion of body image to the point that a restriction or binge/purge anorexia diagnosis could be made. If extreme exercise does lead to AN, it is most likely in a person who is biologically or psychologically at risk (Katz. 2004).
Study #1: Katz
The purpose of Katz’s experiment was to prove that there is an “intimate” relationship between AN and exercise. He accomplished this by studying two cases of long distance runners. He did not have a control group, and the study was small. He also measured his variables by just receiving reports of experiences from subjects and not doing any actual studies of his own. This did not make for a sound experiment, but the results were interesting nonetheless. The important variables were to see if increased physical activity led to decreased caloric intake and weight loss to fit an anorexia diagnosis. The two subjects studied were both male and only ten years apart in age (also a flaw in the experiment).
The first man reported increasing obsession with diet and calorie restriction in pair with increased mileage. He was fascinated with the changes in his body. He also described the development of fear of becoming fat. Within one year he dropped ten pounds and continued to drop weight to an exceptionally unhealthy amount. He began feeling depressed and showed symptoms of bulimia nervosa when he cultivated overuse injuries and could not run.
The second man was at first preoccupied with running more and restricting calories to better his performance in running long distances; not just to lose weight. He noticed that as he ran more and lost weight he was able to run faster. Then he started to fear becoming fat and lapsed into depression when he hurt himself and had to subside from running. The amount of libido he had (which was already low from so much exercise) dropped even further because of anxiety and irritability from not running. He also began displaying bulimic behavior.
These two men’s experiences exemplify that extreme exercise leads to AN, but I do not think the conclusion can be fully trusted yet. Bigger, more diverse studies with closer, more detailed tracking should be completed.
Exercise as a Symptom
Problems with excessive or compulsive exercise may not surface until someone is already diagnosed with or could potentially be diagnosed with AN. Exercise as a symptom of AN, as opposed to a trigger, is different because someone may already be anorexic or partaking in activities that will make them anorexic eventually and then begin to exercise to foster that cause. If the person is a restrictive anorexic they might use exercise as a way to further burn the few calories they are consuming. If the person is a binge/purge anorexic they might use an unnecessary amount of exercise as a way to rid themselves of calories. Also, exercise can suppress appetite, giving anorexics further reason to participate (Peñas-Lledó, 2002). Compulsive exercise, as opposed to long periods of or high intensity exercise, is more strongly correlated to AN. Approximately 80% of anorexia nervosa patients take part in compulsive exercise (Peñas-Lledó, 2002). This is because many sufferers believe they cannot stay thin without exercising every or most every day. Therefore, anorexics that participate in this excessive compulsive exercise are commonly depressed and anxious (Peñas-Lledó, 2002).
Study #2: Peñas-Lledó
Peñas-Lledó’s study objective was to prove that anorexia patients use exercise to regulate their caloric count and body weight. She also wanted to discover whether or not the same behavior was seen in bulimic patients. Her study consisted of 63 AN patients (35 were restrictive and 28 were binge/purge) and 61 BN patients. Even though the study consisted of only girls it was still very thorough because it included a control group of AN and BN patients who did not exercise excessively. The case used a retrospective study and evaluated the women before the development of the study by labeling them as excessive exercisers or non-exercisers. Their BMIs were also measured. Then three questionnaires were given testing eating pathology, bulimic attitudes and behaviors, and psychological status. The important variables measured were AN and BN patients who do and do not exercise excessively against eating pathology and AN and BN patients who do and do not exercise excessively against psychopathology.
The results showed that anorexic patients who exercise excessively had higher levels of bulimic and disordered eating behavior, anxiety, and somatization. Bulimic patients did not show higher eating psychopathology, anxiety, or somatization as a result of excessive exercise. After studying the comprehensive tables of data I think Peñas-Lledó is justified in concluding that anorexics probably find comfort in exercise because it suppresses their emotions. Bulimics find other ways of compensating for their anxious or depressed mood.
Exercise as a Treatment
Exercise as a behavior of an anorexic has a bad reputation for poor recovery outcome. However, in some cases, exercise done in moderation can treat anorexia nervosa. Therefore, the use of exercise as treatment is controversial (Thien, 1999). Patients trying to overcome the disorder may have no idea what a healthy lifestyle looks like. Many anorexics do not exercise at all, which makes sense because it goes along with a restrictive way of life. Sometimes people who do not exercise because they are too lazy or too busy feel guilty about it, and that is why they start curbing their food intake. By adding a healthy exercise routine to an anorexic’s life, their mood and self-confidence could be boosted. They could potentially feel the positive effects on their body such as muscle strength and endurance. As long as the patient is exercising within limits and not compromising the goals of recovery, exercise is beneficial (Thien, 1999). It could lead them to the realization that exercise is crucial to heart health and living longer. Their relationship with food could then further mature into one where they see that food should fuel life and give the body energy and nutrients (Thien, 1999).
Study #3: Thien
The purpose of this study was to test if exercise improves an AN patient’s quality of life without sacrificing gain of body mass index and percent body fat. The experimental group was only made up of sixteen subjects, which probably is not sufficient for a sound study. Also, it only included one male. The patients ranged from 17-45 who were all registered at the same eating disorder outpatient recovery clinic after being diagnosed with AN.
They were studied by initially being asked to answer a quality of life questionnaire. Then they were split into an experimental and control group and followed up on every 2-3 weeks for 3 months. Their follow-ups included checking their body fat, weight, and activity level. The control group was asked to limit activity levels and the experimental group was put on a very specific exercise plan. The exercise plan allowed the patients to progress from basic to more accelerated levels of exercise, but the patients could only progress when a physical therapist deemed it appropriate. Data about quality of life was determined through another questionnaire. In particular, answers to questions about physical activity and how it affects emotion, energy and daily activities were taken into account.
Only 12 followed through with the study, and it was a short study, so the results may not support the conclusion that exercise does boost life quality. Although that is what their data found, recovery from anorexia is a very long process, and there is no way to tell from this study that the subjects’ weight and happiness will continue to stabilize in the long run.
The relationship between exercise and anorexia nervosa is very existent and very codependent. The above three studies attest to this. Exercise, usually unwarranted amounts, can possibly bring about anorexia, surface as a symptom of anorexia or act as an alleviator of anorexia. The affirmative consequences that come from exercising inspire people to increase the frequency, duration, or intensity because they see that hard work pays off on their physical appearance. They then wish to adopt other disordered behaviors to keep pursuing a perfect image. Those already suffering with the disorder view exercise as a way to purge their bodies of calories rather than a recreational activity. Lastly, some use exercise as a way to uplift themselves and become stronger and healthier throughout rehabilitation. As they are gaining weight and changing their lifestyles, a safe exercise program is empowering.
What I still want to understand and hope to see studies on in the future is the connection between normal amounts of exercise and anorexia as opposed to excessive exercise and anorexia. I would also appreciate more research on why anorexics often choose exercise as a way of ridding themselves of calories instead of purging. Does it have to do with the endorphins or maybe the physical benefits? The relationship between exercise and anorexia nervosa is so tightly knit, but it will never be fully understood because of the deep psychological thought processes that stimulate it. It is so difficult for patients to articulate their feelings, and there are too many dimensions and factors to make sense of. That being said, I think the studies that have been done so far have been successful.
Peñas-Lledó, Eva (2002). Excessive exercise in anorexia nervosa and bulimia nervosa: Relation to eating characteristics and general psychopathology. International Journal of Eating Disorders, Volume 31, Issue 4. Retrieved 24 April 2011 from
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