Edited by: Sergio Machado, Salgado de Oliveira University, Brazil
Reviewed by: Jennifer Cumming, University of Birmingham, United Kingdom; Donatella Di Corrado, Kore University of Enna, Italy
This article was submitted to Movement Science and Sport Psychology, a section of the journal Frontiers in Sports and Active Living
†ORCID: Mike Trott
This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
Despite the many benefits of regular, sustained exercise, there is evidence that exercise can become addictive, to the point where the exerciser experiences negative physiological and psychological symptoms, including withdrawal symptoms upon cessation, training through injury, and the detriment of social relationships. Furthermore, recent evidence suggests that the etiology of exercise addiction is different depending on the presence or absence of eating disorders. The aim of this study was to explore to what extent eating disorder status, body dysmorphic disorder, reasons for exercise, social media use, and fitness instructor status were associated with exercise addiction, and to determine differences according to eating disorder status. The key findings showed that the etiology of exercise addiction differed according to eating disorder status, with variables including social media use, exercise motivation, and ethnicity being uniquely correlated with exercise addiction only in populations with indicated eating disorders. Furthermore, body dysmorphic disorder was highly prevalent in subjects without indicated eating disorders, and could be a primary condition in which exercise addiction is a symptom. It is recommended that clinicians and practitioners working with patients who present with symptoms of exercise addiction should be screened for eating disorders and body dysmorphic disorder before treatments are considered.
Exercise can be defined as “structured, intentional physical activity for improving health and fitness” (Garber et al.,
There is evidence, however, that exercise can become obsessive, compulsive, or addictive, to the point where the exerciser experiences negative physiological and psychological symptoms, including withdrawal symptoms upon cessation, training through injury, and the detriments of social relationships (Symons Downs et al.,
Many theoretical models have been proposed to explain EA, including the Sympathetic Arousal Hypothesis [(Thompson and Blanton,
The interactional model of exercise addiction (Egorov and Szabo,
One of the key determinants of EA in the Interactional Model is “sudden or progressively intolerable life-stress.” The most researched of these is the presence (or absence) of eating disorders, with recent evidence concluding that subjects with indicated eating disorders have 3.5x higher risk of developing EA than subjects without indicated eating disorders (Trott et al.,
Another key component of the Interactional Model of EA is “exercise-motivation,” although few studies have explored reasons for exercise in exercise addicted populations. Serier et al. (
Further at the beginning of the Interactional Model is “personal” and “situational” factors. Of these, the amount of leisure time physical activity has been consistently shown to positively correlate with exercise addiction risk (Kovacsik et al.,
Identifying the extent to which these variables are associated with EA has the potential to support, refute, or suggest modifications to the Interactional Model of EA. Furthermore, identifying how much these associations differ between subjects with and without indicated eating disorders is important, as it allows researchers to understand if there are any differences in the two populations, and therefore have suggested different etiology. The aim of this study, therefore, was to answer the following questions:
1. To what extent is eating disorder status, BDD, reasons for exercise, social media use, and fitness instructor status associated with exercise addiction in line with the Interactional Model?
Based on the Interaction Model, it is hypothesized that eating disorder and BDD status (conditions that could be considered a “sudden or progressively intolerable life-stresses”) have the strongest association with EA. Exercise-motivations are hypothesized to have a smaller association, with the personal and situational factors (fitness instructor status and social media use) showing the smallest associations.
2. Do the associations between these psychological and social variables and exercise addiction differ according to eating disorder status?
We hypothesize that some correlates will differ according to eating disorder status.
Not only will this expand the understanding of exercise addiction, its relationship with eating disorders, and its relationship with the multiple variables described above, it has the potential to inform practitioners working with potentially “at risk” groups, such as physicians and fitness industry workers. Furthermore, this study will either support or refute the most recent model of EA, which will steer the direction of future research.
Study participants were recruited via an international group fitness e-newsletter and through Facebook, Instagram, and Twitter from 8/4/19 to 31/7/19 through social media influencers and through the authors' personal social media accounts. Participants provided informed consent prior to taking part in the survey, including the right to withdraw and access to further support if any of the topics were distressing. To be eligible for the study, participants were required to be adult (>18 years) health club users. Participants were oriented to an online battery of questions hosted through an academic survey website (Jisc Online Surveys,
Total, 1,864 participants completed the questionnaire. Of these, 199 (10.7%) failed to confirm that they were health club users and were excluded from further analysis. Of the remaining 1,665 participants, the mean age was 35.7 years (
Sample characteristics.
1,665 | 511 (30.7%) | 1,154 (69.3%) | |
Age (years) | 35.72 (10.92) | 34.47 (10.41) | 36.28 (11.10) |
BMI (kg/m2) | 23.91 (3.93) | 23.64 (4.22) | 24.02 (3.79) |
Sex (female) | 85.00% ( |
89.4% ( |
84.10 ( |
EAI |
21.23 (4.31) | 25.91 (1.73) | 19.17 (3.40) |
Indicated eating disorder (yes) | 16.80% ( |
32.90% ( |
9.60% ( |
EAT-26 |
13.40 (12.43) | 20.07 (14.83) | 10.45 (9.86) |
Fitness instructor (yes) | 42.76% ( |
42.90% ( |
42.70% ( |
Exercise hours for leisure (hour/week) | 6.46 (4.04) | 7.78 (4.50) | 5.87 (3.67) |
Life limiting illness (yes) | 1.14% ( |
0.60% ( |
1.40% ( |
Heterosexual | 88.00% ( |
87.10% ( |
89.40% ( |
Homosexual | 4.62% ( |
4.50% ( |
4.70% ( |
Bisexual | 4.50% ( |
5.70% ( |
4.00% ( |
Prefer not to say | 2.16% ( |
2.20 ( |
1.40% ( |
White | 91.23% ( |
92.80% ( |
90.6% ( |
Black or African American | 0.72% ( |
0.40% ( |
0.90% ( |
Hispanic or Latino | 1.62% ( |
1.00% ( |
1.90% ( |
Asian | 3.78% ( |
3.30% ( |
4.00% ( |
Single | 28.89% ( |
34.10% ( |
26.60% ( |
In a relationship | 32.01% ( |
31.10% ( |
32.40% ( |
Married | 37.40% ( |
33.90% ( |
39.60 ( |
Widowed | 0.24% ( |
0.20% ( |
0.30% ( |
Other | 1.02% ( |
0.80 ( |
0.70% ( |
Homeowner status (yes) | 57.36% ( |
53.40% ( |
59.10% ( |
BDD |
30.51% ( |
48.70% ( |
22.40% ( |
Weight control | 4.64 (1.27) | 5.00 (1.30) | 4.48 (1.23) |
Fitness | 5.88 (0.96) | 6.05 (0.94) | 5.81 (0.96) |
Mood | 5.35 (1.36) | 5.81 (1.19) | 5.14 (1.39) |
Health | 5.99 (1.02) | 6.10 (1.03) | 5.94 (1.01) |
Attractiveness | 4.68 (1.57) | 5.13 (1.55) | 4.48 (1.54) |
Enjoyment | 4.55 (1.51) | 4.83 (1.52) | 4.43 (1.49) |
Tone | 4.52 (1.51) | 4.70 (1.53) | 4.44 (1.50) |
Social integration and emotional connection | 2.59 (1.12) | 2.82 (1.16) | 2.49 (1.08) |
Integration into social routines | 4.11 (1.18) | 4.24 (1.20) | 4.05 (1.17) |
The Exercise Addiction Inventory (EAI) (Terry et al.,
Note: Despite having a cut-off score, the EAI was used as a continuous variable indicting severity of exercise addiction risk because there are no clinically recognized diagnostic criteria for exercise addiction (American Psychiatric Association,
Social media use was measured using the Social Media Use Integration Scale (SMUIS) (Jenkins-Guarnieri et al.,
Reasons for exercise was measured using the Reasons for Exercise Inventory (REI) (Silberstein et al.,
BDD was measured using the Body Dysmorphic Disorder Questionnaire (BDDQ) (Phillips,
Eating disorder symptomology was measured using the Eating Attitudes Test 26 (EAT-26) (Garner et al.,
Participants were required to answer yes/no to indicate whether they were a current health club user.
Participants were required to answer yes/no to indicate if they were currently a fitness instructor.
Participants were required to indicate how many hours per week they participated in physical activity (if the subject was a fitness instructor, this did not include exercise hours as part of work).
All data were analyzed using SPSS Version 26 (IBM Corp.,
Exercise addiction prevalence was also calculated in all the total sample and both indicated and non-indicated eating disorder populations.
A hierarchical multiple linear regression was run on the total sample to determine if the addition of variables significantly added to the total model with EAI score (as a continuous variable) as the dependent variable. The variables were added to the previous models in the following order:
Model 1: Age, gender, BMI, ethnicity, life limiting illness
Model 2: Eating disorder status
Model 3: BDD status
Model 4: Reasons for exercise (all items)
Model 5: Fitness instructor status
Model 6: Social media use (all items)
Model 7: Sexuality
Model 8: Exercise hours for leisure
Model 9: Relationship status
Furthermore, a linear regression was used to analyse associations between exercise addiction score (as a continuous variable) and: age, sex, BMI, ethnicity, eating disorder status, homeowner status, relationship status, both subscales of the SMUIS, all subscales of the REI, being a fitness instructor, leisure time physical activity, sexuality, and BDD status in two populations:
Indicated eating disorders (defined as scoring ≥20 in the EAT-26)
No indicated eating disorders (defined as scoring <20 in the EAT-26)
Any missing data was tested for randomness via Little's MCAR test (Little,
In order to explore whether associations varied according to eating disorder status, we repeated the multivariable analysis (model 9) in a series of linear regression models adding the interaction term (eating disorder status*respective variable) between eating disorder status and each potential correlate in turn (e.g., in the first analysis we included all variables in model 9 with the addiction of the variable “eating disorder status*age”; in the second analysis we included all variables in model 9 with the addiction of the variable “eating disorder status*gender”, etc.).
The prevalence of exercise addiction, as defined by a score of ≥24 on the EAI (Terry et al.,
There was linearity in all samples as assessed by partial regression plots and a plot of studentized residuals against the predicted values. There was independence of residuals in all populations, as assessed by a Durbin-Watson statistic of 2.108, 1.087, and 2.036 in the total sample, indicated ED and no indicated ED samples, respectively. Homoscedasticity was as assessed by visual inspection of a plot of studentized residuals vs. unstandardized predicted values, with evidence of homoscedasticity in all three samples. There was no evidence of multicollinearity in any sample, as assessed by tolerance values >0.1. There were 23 studentized deleted residuals >±3 standard deviations, which were kept in the analysis. The assumption of normality was met, as assessed by a Q-Q Plot. The Little's MCAR test confirmed that all missing data was random (
In the total sample, each model significantly added to the total R2, apart from models 5, 7, and 9 (the respective addition of fitness instructor status, sexuality, and relationship status into the previous model). The final multiple regression model (model 9) was statistically significant [
Hierarchical regression in the total sample (exercise addiction inventory scores as the dependent variable).
Variable | Beta coefficients (95%CI) | Beta coefficients (95%CI) | Beta coefficients (95%CI) | Beta coefficients (95%CI) | Beta coefficients (95%CI) | Beta coefficients (95%CI) | Beta coefficients (95%CI) | Beta coefficients (95%CI) | Beta coefficients (95%CI) | |||||||||
Age | −0.106 (−0.156; −0.056) | <0.001 |
−0.084 (−0.133; −0.036) | 0.001 | −0.056 (−0.105; −0.006) | 0.027 | −0.044 (−0.093; 0.005) | 0.081 | −0.045 (−0.094; 0.004) | 0.073 | −0.038 (−0.087; 0.012) | 0.138 | −0.036 (−0.086; 0.014) | 0.156 | −0.046 (−0.095; 0.002) | 0.061 | −0.042 (−0.102; 0.017) | 0.165 |
Sex | −0.052 (−0.103; −0.002) | <0.001 |
−0.022 (−0.071; 0.027) | 0.385 | −0.005 (−0.054; 0.044) | 0.843 | 0.020 (−0.029; 0.069) | 0.417 | 0.020 (−0.029; 0.068) | 0.432 | 0.021 (−0.028; 0.070) | 0.404 | 0.023 (−0.030; 0.075) | 0.392 | 0.004 (−0.047; 0.055) | 0.881 | 0.004 (−0.048; 0.055) | 0.888 |
BMI | −0.064 (−0.115; −0.014) | 0.012 | −0.055 (−0.104; −0.006) | 0.027 | −0.067 (−0.115; −0.018) | 0.007 | −0.071 (−0.118; −0.025) | 0.003 | −0.071 (−0.118; −0.025) | 0.003 | −0.074 (−0.121; −0.028) | 0.002 | −0.074 (−0.121; −0.028) | 0.002 | −0.049 (−0.094; −0.003) | 0.037 | −0.048 (−0.094; −0.002) | 0.039 |
Ethnicity: white vs. Hispanic | −0.013 (−0.062; 0.037) | 0.613 | −0.011 (−0.059; 0.037) | 0.659 | −0.011 (−0.059; 0.036) | 0.643 | −0.016 (−0.061; 0.030) | 0.494 | −0.017 (−0.063; 0.0.029) | 0.465 | −0.013 (−0.058; 0.033) | 0.585 | −0.016 (−0.062; 0.030) | 0.500 | −0.011 (−0.056; 0.033) | 0.614 | −0.011 (−0.056; 0.033) | 0.620 |
Ethnicity: white vs. black | −0.091 (−0.140; −0.041) | <0.001 |
−0.099 (−0.147; −0.051) | <0.001 |
−0.094 (−0.142; −0.046) | <0.001 |
−0.066 (−0.112; −0.020) | 0.005 | −0.066 (−0.112; −0.020) | 0.005 | −0.065 (−0.111; −0.019) | 0.006 | −0.068 (−0.113; −0.022) | 0.004 | −0.071 (−0.115; −0.026) | 0.002 | −0.071 (−0.116; −0.027) | 0.002 |
Ethnicity: white vs. Asian | −0.020 (−0.070; 0.029) | 0.423 | −0.021 (−0.070; 0.027) | 0.388 | −0.015 (−0.063; 0.033) | 0.530 | −0.026 (−0.072; 0.020) | 0.270 | −0.025 (−0.071; 0.021) | 0.290 | −0.027 (−0.073; 0.019) | 0.253 | −0.029 (−0.075; 0.017) | 0.216 | −0.045 (−0.090; 0.000) | 0.050 | −0.048 (−0.094; −0.003) | 0.038 |
Ethnicity: white vs. “other” | 0.001 (−0.049; 0.051) | 0.970 | 0.005 (−0.043; 0.053) | 0.842 | 0.009 (−0.039; 0.057) | 0.708 | −0.005 (−0.050; 0.041) | 0.843 | −0.004 (−0.050; 0.042) | 0.855 | −0.004 (−0.050; 0.041) | 0.855 | −0.004 (−0.050; 0.041) | 0.850 | −0.005 (−0.050; 0.039) | 0.817 | −0.006 (−0.051; 0.039) | 0.795 |
Life limiting illness | −0.040 (−0.089; 0.010) | 0.120 | −0.046 (−0.094; 0.003) | 0.065 | −0.041 (−0.089; 0.007) | 0.096 | −0.046 (−0.092; 0.000) | 0.048 | −0.046 (−0.092; 0.000) | 0.050 | −0.048 (−0.094; −0.002) | 0.041 | −0.051 (−0.097; −0.005) | 0.031 | −0.055 (−0.100; −0.011) | 0.015 | −0.055 (−0.100; −0.010) | 0.017 |
Eating disorder status | 0.233 (0.185; 0.282) | <0.001 |
0.163 (0.109; 0.217) | <0.001 |
0.135 (0.082; 0.188) | <0.001 |
0.136 (0.083; 0.189) | <0.001 |
0.135 (0.083; 0.188) | <0.001 |
0.134 (0.081; 0.187) | <0.001 |
0.106 (0.054; 0.158) | <0.001 |
0.106 (0.054; 0.159) | <0.001 |
||
BDD status | 0.162 (0.107; 0.218) | <0.001 |
0.123 (0.069; 0.178) | <0.001 |
0.123 (0.068; 0.178) | <0.001 |
0.117 (0.062; 0.172) | <0.001 |
0.119 (0.064; 0.174) | <0.001 |
0.112 (0.058; 0.165) | <0.001 |
0.111 (0.057; 0.164) | <0.001 |
||||
REI weight control | 0.067 (0.012; 0.122) | 0.018 | 0.067 (0.012; 0.122) | 0.018 | 0.065 (0.010; 0.120) | 0.020 | 0.064 (0.009; 0.119) | 0.023 | 0.060 (0.006; 0.113) | 0.030 | 0.060 (0.006; 0.114) | 0.030 | ||||||
REI fitness | 0.067 (0.007; 0.127) | 0.028 | 0.065 (0.005; 0.125) | 0.035 | 0.062 (0.002; 0.122) | 0.043 | 0.060 (0.000; 0.120) | 0.052 | 0.043 (−0.016; 0.102) | 0.154 | 0.044 (−0.015; 0.103) | 0.144 | ||||||
REI mood | 0.205 (0.150; 0.260) | <0.001 |
0.205 (0.150; 0.260) | <0.001 |
0.202 (0.147; 0.257) | <0.001 |
0.201 (0.146; 0.256) | <0.001 |
0.200 (0.147; 0.254) | <0.001 |
0.199 (0.146; 0.253) | <0.001 |
||||||
REI health | −0.051 (−0.115; 0.014) | 0.122 | −0.050 (−0.115; 0.014) | 0.125 | −0.036 (−0.101; 0.029) | 0.281 | −0.035 (−0.101; 0.030) | 0.288 | −0.021 (−0.084; 0.043) | 0.521 | −0.021 (−0.085; 0.043) | 0.523 | ||||||
REI attractiveness | 0.048 (−0.008; 0.104) | 0.096 | 0.050 (−0.007; 0.106) | 0.084 | 0.034 (−0.023; 0.091) | 0.236 | 0.038 (−0.019; 0.095) | 0.195 | 0.049 (−0.007; 0.105) | 0.084 | 0.049 (−0.007; 0.106) | 0.085 | ||||||
REI enjoyment | 0.105 (0.054; 0.156) | <0.001 |
0.101 (0.049; 0.152) | <0.001 |
0.094 (0.042; 0.146) | <0.001 |
0.095 (0.043; 0.146) | <0.001 |
0.070 (0.019; 0.121) | 0.007 | 0.068 (0.017; 0.119) | 0.009 | ||||||
REI tone | −0.038 (−0.086; 0.010) | 0.121 | −0.040 (−0.088; 0.008) | 0.105 | −0.040 (−0.088; 0.008) | 0.099 | −0.041 (−0.089; 0.007) | 0.092 | −0.044 (−0.091; 0.002) | 0.063 | −0.044 (−0.091; 0.003) | 0.068 | ||||||
Fitness instructor status | 0.024 (−0.023; 0.071) | 0.323 | 0.018 (−0.029; 0.065) | 0.460 | 0.017 (−0.030; 0.064) | 0.485 | 0.063 (0.016; 0.110) | 0.009 | 0.063 (0.016; 0.111) | 0.009 | ||||||||
SMUIS social integration and emotional connection | 0.086 (0.024; 0.148) | 0.006 | 0.085 (0.023; 0.148) | 0.007 | 0.084 (0.024; 0.145) | 0.006 | 0.083 (0.023; 0.144) | 0.007 | ||||||||||
SMUIS integration into social routines | −0.024 (−0.084; 0.036) | 0.430 | −0.024 (−0.084; 0.036) | 0.436 | −0.004 (−0.063; 0.065) | 0.884 | −0.003 (−0.061; 0.056) | 0.932 | ||||||||||
Sexuality: heterosexual vs. homosexual | 0.013 (−0.062; 0.087) | 0.739 | −0.013 (−0.086; 0.059) | 0.723 | −0.013 (−0.086; 0.061) | 0.735 | ||||||||||||
Sexuality: heterosexual vs. bisexual | 0.024 (−0.042; 0.089) | 0.481 | 0.001 (−0.063; 0.065) | 0.983 | 0.002 (−0.062; 0.066) | 0.950 | ||||||||||||
Sexuality: heterosexual vs. “prefer not to say” | 0.045 (−0.010; 0.099) | 0.106 | 0.032 (−0.021; 0.085) | 0.242 | 0.031 (−0.022; 0.085) | 0.248 | ||||||||||||
Exercise hours for leisure (hour/week) | 0.217 (0.170; 0.264) | <0.001 |
0.214 (0.167; 0.262) | <0.001 |
||||||||||||||
Relationship status: single vs. “in a relationship” | 0.001 (−0.075; 0.035) | 0.969 | ||||||||||||||||
Relationship status: single vs. married | −0.020 (−0.088; 0.038) | 0.477 | ||||||||||||||||
Relationship status: single vs. widowed | −0.025 (−0.033; 0.058) | 0.442 | ||||||||||||||||
Relationship status: single vs. “other” | 0.013 (−0.033; 0.058) | 0.586 |
Both populations' full regression models were statically significant [indicated eating disorders =
Multiple linear regression summary of independent variables (dependent variable = exercise addiction inventory total score).
Age | 0.027 (−0.140; 0.194) | 0.751 | −0.046 (−0.112; 0.020) | 0.171 |
Sex | 0.059 (−0.067; 0.184) | 0.357 | −0.011 (−0.069; 0.047) | 0.708 |
BMI |
−0.189 (−0.316; −0.062) | 0.004 |
−0.013 (−0.064; 0.038) | 0.616 |
Life limiting illness | −0.131 (−0.254; −0.008) | 0.038 |
−0.041 (−0.091; 0.009) | 0.107 |
Fitness instructor status | −0.068 (−0.176; 0.060) | 0.297 | 0.093 (0.040; 0.146) | 0.001 |
Exercise hours for leisure | 0.156 (0.031; 0.280) | 0.014 |
0.246 (0.194; 0.298) | <0.001 |
Homeowner status | 0.009 (−0.138; 0.156) | 0.903 | 0.006 (−0.056; 0.068) | 0.852 |
REI weight control | 0.008 (−0.125; 0.140) | 0.907 | 0.065 (0.007; 0.122) | 0.028 |
REI fitness | 0.100 (−0.081; 0.282) | 0.277 | 0.024 (−0.039; 0.087) | 0.456 |
REI mood |
0.055 (−0.102; 0.213) | 0.491 | 0.244 (0.185; 0.302) | <0.001 |
REI health | 0.022 (−0.182; 0.226) | 0.833 | −0.015 (−0.082; 0.053) | 0.668 |
REI attractiveness |
−0.046 (−0.188; 0.097) | 0.528 | 0.078 (0.017; 0.139) | 0.013 |
REI enjoyment | 0.028 (−0.117; 0.174) | 0.700 | 0.075 (0.019; 0.131) | 0.009 |
REI tone | 0.089 (−0.032; 0.211) | 0.149 | −0.078 (−0.130; −0.026) | 0.003 |
SMUIS social integration and emotional connection | 0.204 (0.048; 0.361) | 0.011 |
0.067 (−0.001; 0.135) | 0.054 |
SMUIS integration into social routines | −0.124 (−0.282; 0.033) | 0.121 | 0.022 (−0.043; 0.088) | 0.509 |
BDD status | 0.056 (−0.076; 0.187) | 0.405 | 0.103 (0.050; 0.157) | <0.001 |
Sexuality: Heterosexual vs. homosexual | 0.038 (−0.221; 0.297) | 0.773 | −0.025 (−0.104; 0.054) | 0.539 |
Sexuality: heterosexual vs. bisexual | 0.085 (−0.149; 0.319) | 0.476 | −0.029 (−0.098; 0.040) | 0.411 |
Sexuality: heterosexual vs. “prefer not to say” | 0.135 (−0.037; 0.308) | 0.123 | 0.016 (−0.042; 0.074) | 0.595 |
Relationship status: single vs. “in a relationship” | −0.051 (−0.193; 0.090) | 0.476 | −0.005 (−0.066; 0.057) | 0.884 |
Relationship status: single vs. married | −0.070 (−0.227; 0.087) | 0.381 | −0.013 (−0.084; 0.058) | 0.724 |
Relationship status: single vs. widowed | NA | NA | 0.015 (−0.036; 0.065) | 0.567 |
Relationship status: single vs. “other” | −0.026 (−0.147; 0.096) | 0.675 | −0.006 (−0.056; 0.045) | 0.827 |
Ethnicity: white vs. Hispanic | −0.118 (−0.234; 0.003) | 0.045 |
0.004 (−0.046; 0.054) | 0.871 |
Ethnicity: white vs. black |
−0.320 (−0.443; −0.196) | <0.001 |
−0.005 (−0.055; 0.044) | 0.832 |
Ethnicity: white vs. Asian | −0.139 (−0.261; −0.017) | 0.026 |
−0.024 (−0.075; 0.027) | 0.358 |
Ethnicity: white vs. “other” | −0.038 (−0.156; 0.080) | 0.524 | −0.001 (−0.049; 0.051) | 0.959 |
There were significant interactions between eating disorder status and BMI, exercising for mood, exercising for attractiveness, and ethnicity (black vs. white). Full interaction data are shown in
Interaction effects between independent variables and eating disorder status (dependent variable = exercise addiction inventory total score).
Age | 0.001 (−0.051; 0.052) | 0.993 |
Sex |
0.017 (−0.030; 0.064) | 0.480 |
BMI | −0.260 (−0.497; −0.023) | 0.032 |
Life limiting illness |
−0.025 (−0.076; 0.025) | 0.331 |
Fitness instructor status |
−0.053 (−0.112; 0.006) | 0.081 |
Exercise hours for leisure | −0.069 (−0.162; 0.023) | 0.140 |
Homeowner status |
−0.022 (−0.885; 0.045) | 0.516 |
REI weight control | −0.185 (−0.403; 0.034) | 0.097 |
REI fitness | −0.057 (−0.293; 0.179) | 0.637 |
REI mood | −0.314 (−0.510; −0.119) | 0.002 |
REI health | −0.148 (−0.369; 0.073) | 0.190 |
REI attractiveness | −0.196 (−0.365; −0.027) | 0.023 |
REI enjoyment | −0.089 (−0.217; 0.039) | 0.172 |
REI tone | 0.094 (−0.055; 0.243) | 0.217 |
SMUIS social integration and emotional connection | −0.007 (−0.128; 0.114) | 0.911 |
SMUIS integration into social routines | −0.113 (−0.281; 0.055) | 0.187 |
BDD status |
−0.032 (−0.130; 0.066) | 0.521 |
Sexuality: heterosexual vs. homosexual |
−0.099 (−0.246; 0.048) | 0.187 |
Sexuality: heterosexual vs. bisexual |
0.041 (−0.010; 0.092) | 0.112 |
Sexuality: heterosexual vs. “prefer not the say” |
0.021 (−0.029; 0.071) | 0.413 |
Relationship status: single vs. “in a relationship” |
0.004 (−0.060; 0.068) | 0.902 |
Relationship status: single vs. married |
−0.013 (−0.068; 0.042) | 0.645 |
Relationship status: single vs. widowed |
NA (not enough data) | – |
Relationship status: single vs. “other” |
−0.002 (−0.068; 0.064) | 0.953 |
Ethnicity: white vs. Hispanic |
−0.043 (−0.091; 0.005) | 0.077 |
Ethnicity: white vs. black |
−0.104 (−0.159; −0.049) | <0.001 |
Ethnicity: white vs. Asian |
−0.048 (−0.098; 0.002) | 0.059 |
Ethnicity: white vs. “other” |
−0.019 (−0.067; 0.029) | 0.442 |
The present study explored the prevalence of exercise addiction among fitness club users, the extent to which age, BMI, gender, sexuality, social media use, BDD, fitness instructor status, eating disorder status, and reasons for exercise were associated with exercise addiction scores, and whether these correlates differed according to eating disorder status. The prevalence of exercise addiction in the total sample was 30.7%, with prevalence rates differing largely according to eating disorder status (indicated eating disorders 60.2%; no indicated eating disorders 24.7%). Characteristics associated with higher exercise addiction scores in multivariable models included: indicated eating disorder, being a fitness instructor, leisure-time physical activity, exercising to improve mood, enjoyment, and for weight control, indicated BDD, and using social media for social integration and emotional connection. Characteristics associated with lower exercise addiction scores included: a higher BMI, reporting a life-limiting illness, and ethnicity (black vs. white and Asian vs. white). There were significant interactions between eating disorder status and BMI, exercising for mood, exercising for attractiveness, and ethnicity (black vs. white).
The hierarchical regression showed that the addition of all variables into the model significantly increased the
As hypothesized, the strength of associations of the two variables that could be interpreted as “sudden or progressively intolerable life-stress” (eating disorder status and BDD status) in the Interactional Model of EA were among the strongest. This concurs with several studies that have shown that eating disordered subjects suffer from higher EA (Fietz et al.,
Unsurprisingly, leisure-time physical activity was a significant correlate of higher scores of exercise addiction, which concurs with the literature (Hausenblas and Downs,
Lower BMI, using social media for social integration and emotional connection, and ethnicity (white vs. black, Hispanic, and Asian) were only positively associated with higher exercise addiction scores among health club users with indicated eating disorders, and fitness instructor status, exercising to improve mood, attractiveness, exercising for enjoyment, and BDD status were only associated with higher exercise addiction scores among health club users without an indicated eating disorder.
Lower BMI was a correlate of higher exercise addiction scores only in health club users who had an indicated eating disorder. This is consistent with the eating disorder literature which states that striving for a lower body weight (and therefore a lower BMI) via excessive exercise is a common symptom of both anorexia and bulimia nervosa (Abraham,
Participants who identified as fitness instructors had a slightly higher risk of higher exercise addiction scores than health club users who did not identify as fitness instructors; however, in the sub-populations this was only present in participants who showed no indicated eating disorders. One possible reason is because of the expectation of fitness instructors to exercise as part of their role, and the expectation of superior levels of fitness compared to regular health club users (Thompson et al.,
Participants who reported exercising to improve their mood, to be more attractive, weight control, tone, and for enjoyment had higher exercise addiction scores; however, this was only seen in participants who had no indicated eating disorders. This is broadly consistent with previous studies that have found that exercising for mood, appearance, and enjoyment is positively correlated with exercise addiction (Serier et al.,
Participants with indicated BDD were significantly more likely to yield higher exercise addiction scores, but only in participants without indicated eating disorders. Although this concurs with several studies that have shown that negative self-body image is positively correlated with exercise addiction (Klein et al.,
In the group with indicated eating disorders, participants from ethnic minorities (black, Hispanic, and Asian vs. being white) yielded higher exercise addiction scores. This is the first time such a finding has been reported, and this could be because of the long-recognized limited treatment barriers to eating disorders that subjects from ethnic minorities face (Cachelin et al.,
The prevalence of exercise addiction was high in this sample, with 30.7% being classified as at risk of exercise addiction. Prevalence rates differed largely according to eating disorder status, with participants with indicated eating disorders yielding more than double the prevalence rates than those with no indicated eating disorders. These results are broadly in agreement with a recent meta-analysis that showed subjects with indicated eating disorders are over 3.5 times more likely to also have exercise addiction (Trott et al.,
This study had several limitations. Firstly, due to the cross-sectional nature of the study design, the direction of correlation (and therefore causality) is impossible to determine. Further longitudinal analysis is required to determine the direction of the observed correlations. Secondly, it has been reported that the EAI can yield false-positive results in elite athletes (Szabo et al.,
The key findings from this study suggest a direct link between exercise motivations and EA, especially if the reason for exercising is to modify mood state. It is suggested that exercising to modify mood state, eating disorder status, and BDD status be included in the intolerable life-stress section of the Interactional Model of EA.
Furthermore, this study shows that the etiology of EA differs according to eating disorder status, with variables including social media use, exercise motivation, and ethnicity being uniquely correlated with EA only in populations with indicated eating disorders. Furthermore, BDD is also highly prevalent in subjects without indicated eating disorders and could be a primary condition in which exercise addiction is a symptom. It is recommended that clinicians and practitioners working with patients who present with symptoms of EA should be screened for eating disorders and BDD before treatments are considered, as both eating disorders and BDD have considerably higher co-morbid outcomes than EA, and therefore need to be treated as a primary condition. Furthermore, treatment programs already exist for these two primary conditions and therefore can be implemented easier. The development of screening tools that are able to stratify these populations would be beneficial to both researchers and practitioners.
The datasets generated for this study are available on request to the corresponding author.
The studies involving human participants were reviewed and approved by Anglia Ruskin University Sport and Exercise Sciences Departmental Ethics Panel (ESPGR-03). The patients/participants provided their written informed consent to participate in this study.
MT and LS: study design, data collection, data analysis, and write up. BS, JF, SJ, and LY: study design, data analysis, and write up. CG: study design and write up. All authors contributed to the article and approved the submitted version.
The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.