What is the relationship between exercise addiction and eating disorders?
In previous blogs I briefly examined both exercise addiction and eating addiction. However, there is some research that these two disorders sometimes co-occur. In some of the papers I have co-written we have reviewed the evidence as to whether exaggerated exercise behaviour is a primary problem in the affected person’s life or whether it emerges as a secondary problem in consequence of another psychological dysfunction.
Dr. Mark Griffiths is Distinguished Professor of Behavioural Addiction and Director of the International Gaming Research Unit in the Psychology Department at Nottingham Trent University (UK). He has published over 620 refereed research papers, five books, 150+ book chapters and over 1,500 other articles, and has won 18 national and international awards for his research.
Editor: Nadeem Noor
In the former case, the dysfunction is usually classified as primary exercise addiction because it manifests itself as a form of behavioural addiction. In the latter case, it is usually termed as secondary exercise addiction because it co-occurs with another dysfunction, typically with eating disorders, such as anorexia nervosa or bulimia nervosa.
In primary exercise addiction, the motive for over-exercising is typically geared toward avoiding something negative, although the affected individual may be totally unaware of their motivation. It is a form of escape response to a source of disturbing, persistent, and uncontrollable stress. However, in the case of a secondary exercise addiction, the excessive exercise is used as a means of weight loss (in addition to very strict dieting). Thus, secondary exercise addiction has a different etiology than primary exercise addiction. Nevertheless, it should be highlighted that many symptoms and consequences of exercise addiction are similar whether it is a primary or a secondary exercise addiction. The distinguishing feature between the two is that in primary exercise addiction, the exercise is the main objective, whereas in secondary exercise addiction, weight loss is the main objective, while exaggerated exercise is one of the primary means in achieving the objective.
In a qualitative study published by Dr Diane Bamber, she and her team interviewed 56 regularly exercising adult women. On the basis of the analysis of the results, the authors identified three factors in the diagnostic criteria of secondary exercise addiction. Among these factors, only the presence of eating disorder symptoms differentiated secondary from primary exercise addiction. The other two factors (i.e., dysfunctional psychological, physical, or social behaviour, and the presence of withdrawal symptoms) were nonspecific to secondary exercise addiction.
However, Dr Michelle Blaydon and colleagues attempted to further sub-classify secondary exercise addiction based on the primary source of the problem, which in their view was related to either a form of eating disorder or to an exaggerated preoccupation with body image. Although this appears to have face validity, to date, there is no empirical evidence for such speculation. Furthermore, a different research study by Dr Diane Bamber found no evidence for primary exercise addiction. In fact, they believe that all problematic exercise behaviours are linked to eating disorders. However, this view remains critically challenged in the literature and there are documented case studies – including one that I published myself back in 1997 where no eating disorders were present at all.
In addition to several studies that have reported disordered eating behaviour often (if not always) accompanied by exaggerated levels of physical exercise, the reverse relationship has also been established. Individuals affected by exercise addiction often (but not always) show an excessive concern about their body image, weight, and control over their diet. This co-morbidity makes it difficult to establish which is the primary disorder. This dilemma has been investigated using trait and personality-oriented investigations. In an early but widely cited controversial study led by Dr Alayne Yates concluded that addicted male long-distance runners resembled anorexic patients on a number of personality dispositions (e.g., introversion, inhibition of anger, high expectations, depression, and excessive use of denial) and labelled the similarity as the ‘anorexia analogue’ hypothesis.
To further test the hypothesis, Yates and colleagues examined the personality characteristics of 60 male obligatory exercisers and then compared their profiles with those of clinical patients diagnosed with anorexia nervosa. While the study did not lend support to the hypothesis, the authors claimed that running and extreme dieting were both dangerous attempts to establish an identity, as either addicted to exercise or anorexic. The study has been criticized for a number of shortcomings, including the lack of supporting data, poor methodology, lack of relevance to the average runner, over-reliance on extreme cases or individuals, and exaggerating the similarities between the groups.
Indeed, later investigations also failed to reveal similarities between the personality characteristics of people affected by exercise addiction and those suffering from eating disorders. Therefore, the anorexia analogue hypothesis has failed to secure empirical support. Numerous studies have further examined the relationship between exercise addiction and eating disorders but no consensus has emerged. One reason for the inconsistent findings may be attributed to the fact that the extent of co-morbidity could vary from case to case depending on personality predispositions, the underlying psychological problem that has led to exercise addiction, and/or the interaction of the two, as well as the form and severity of the eating disorder.
A French study led by Professor Michel Lejoyeaux on 125 Parisian male and female current exercise addicts reported that 70% of their sample were bulimic. In another US study by Dr Patricia Estok and Dr Ellen Rudy among 265 young American adult women runners and non-runners, 25% of those who ran more than 30 miles per week showed a high risk for anorexia nervosa. In studies of people with eating disorders, a study by Peter Lewinsohn found excessive exercise activity among males with binge eating disorders, but not females. However, the percentage overlap was not reported. Finally, in a review by Marilyn Freimuth, she and her colleagues reported that among people with eating disorders, 39% to 48% also experienced an exercise addiction.
Basically, the major weakness of the literature is the complete lack of large-scale studies. In a recent review of the addiction co-morbidity literature that I did with Dr Steve Sussman and Nadra Lisha (University of Southern California), we didn’t locate a single study on the co-occurrence of exercise addiction with other disorders with a sample size of more than 500 participants.