Exercise addiction: too much of a good thing?

SPB looks at new research on who is most at risk of getting unhealthily hooked on training!

Decades of research has shown beyond doubt that exercise produces huge positive benefits, including greatly reduced risk of cardiovascular disease, diabetes, certain types of cancer and improved mental health^(1,2). However, it was also understood as far back as the 1970s that excessive exercise was detrimental to physical and mental health, and subsequent research led researchers to identify the phenomenon of ‘exercise addiction’⁽³⁾.

What is exercise addiction?

Exercise addiction is described as a condition where the individual exercises in a compulsive manner rather than in a rational manner – ie where logic and defined goals are used to determine when and how to exercise. In other words, the individual is unable to control his or her exercise habits, even if they are detrimental to training goals, health and well being. It has been suggested that exercise addiction can be characterized by six criteria (see this article for a full discussion):

• Salience – This occurs when a particular activity (eg running, cycling, swimming etc) becomes the most important activity in a person’s life, and which dominates their thinking, feeling, and behavior. In particular, if a person is not exercising due to work or family commitments, he or she will be spend most of the time thinking about exercising or training.
• Mood modification – Addicted exercisers experience a change in their mood as a consequence of exercising or training. As such, addicted exercisers engage in exercise to change their mood to experience a high, or even to calm them down.
• Tolerance – Athletes are required to continuously increase their levels of exercise in order to achieve the effects they used to receive. For example, a person addicted to gambling may have to increase the size of the bet to experience the same euphoria that was previously obtained from placing a smaller bet. This is the same for exercise.
• Withdrawal symptoms – Exercise addicts experience a range of withdrawal symptoms when they are unable to exercise (eg moodiness, irritability, anxiety).
• Conflict – This relates to interpersonal conflicts with spouses, friends, and family due to the amount of time the person dedicates to their sport/training.
• Relapse – Although athletes may cease engaging in extreme exercise, they are susceptible to relapses in which they engage in previous levels of exercise.

How common is exercise addiction?

The prevalence of exercise addiction in the general population is still disputed, with inconsistent findings in research. There does however appear to be a sport-specific variation in prevalence, with endurance sport athletes at particular risk, with as many as 20% displaying some signs of addiction^(4,5). In more typical fitness populations, prevalence ranges from 6.8 to 10.2%⁽⁶⁾, with cross-fit athletes reporting around 5% prevalence⁽⁷⁾, and soccer players just over 7% prevalence⁽⁸⁾.

What are the risk factors for exercise addiction?

Exercise addiction has been linked to a number of other psychiatric diagnoses, but most notably in those involving eating disorders such as anorexia nervosa or bulimia nervosa⁽⁹⁾. Another possible risk factor for exercise addiction is where ‘muscle dysmorphia’ in athletes (where there is an obsession with muscularity and leanness)⁽¹⁰⁾.

This aspect could be relevant for strength athletes since research shows that among weightlifters, 13–44% have a lifetime prevalence of muscle dysmorphia, yet rarely identify with the disorder⁽¹¹⁾. Linked to muscle dysmorphia is the use of anabolic steroids, which are not only used by some athletes to enhance performance, but also to promote muscle gain and leanness; research shows that anabolic steroid use is most likely among athletes who train with high frequencies and training loads⁽¹²⁾.

New research

The risk factors for exercise addiction remain poorly understood, complicated by the presence of eating disorders and muscle dysmorphia. However, identifying athletes at risk before exercise habits become destructive is important – not just for athlete health, but also for ensuring maximum athletic potential is reached. In a new study just published by a team of Swedish scientists, researchers have attempted to try and unravel some of the risk factors for exercise addiction – in particular to see whether any common behavioral traits can help identify those at risk⁽¹³⁾.

Published in the journal ‘Frontiers in Sport and Active Living’, the goal of the study was to explore maladaptive behaviors among physically active individuals, including exercise dependence and use of anabolic steroids. To do this, 3,029 participants completed a detailed questionnaire about their exercise habits and other aspects of their behavior. To be eligible to take part, the participants had to have been exercising for more than three times per week and over 15 years old. The questions analyzed three elements relating to exercise addiction and used the following:

• The exercise addiction inventory (EAI) - a six-question based screening tool where the participant chooses from 1–5 on a scale where 1 = ‘strongly disagree’, 5 = ‘strongly agree’ (total scores between 6 and 30). This tool was chosen as it is not sport-specific, and easy to use.
• The SCOFF (Sick, Control, One stone, Fat, Food) score (see box 1) - used for screening eating disorders, and which consists of five ‘yes’ or ‘no’ questions screening for ED. Two or more yes answers indicate that an eating disorder is likely to be present.
• The AUDIT alcohol consumption questions (AUDIT-C) - a short 3-question screening version of the Alcohol Use Disorders Identification Test (AUDIT) and only focuses on consumption.

In addition to the screening tools listed above, the survey contained multiple choice-questions about exercise type (body-builder, runner, other endurance training, other) and exercise frequency (days per week, 3–7). ‘Yes/no’ questions regarding a variety of psychiatric disorders, smoker status and past-year use of illicit drugs or anabolic were also included, but the participants were given with option of “would not like to respond”.

---

Box 1: The SCOFF screening tool

SCOFF is a validated 5-question screening question tool to clarify suspicion that an eating disorder might exist. The questions are as follows:

1. Do you make yourself sick because you feel uncomfortably full?
2. Are you scared to lose control over how much you eat?
3. Have you recently lost more than 5 kg in a three month period?
4. Do you believe others when they say you are not thin?
5. Would you say that food dominates your life?

An answer of ‘yes’ to two or more questions warrants further questioning and a more comprehensive assessment.

---

The findings

The main findings of this study were as follows:

• A total of 11% of the athletes screened positive for being at risk of exercise addition.
• Nearly a quarter (23%) of the participants screened positive for some kind of eating disorder.
• The risk of an athlete being screened positive for exercise addiction was increased by daily exercise (ie where no rest days were taken), the presence of an eating disorder, athletes who had social phobias (eg excessive shyness), and those with obsessive compulsive behaviors (eg highly rigid habits and routines).
• Regular consumers of alcohol were deemed to be at LOWER risk of exercise addiction.
• Thirty seven participants had used anabolic steroids over the previous year but this did not predict a link to exercise addiction.

Implications for athletes and coaches

This study adds some further clarity regarding which athletes are most likely to be at risk from developing exercise addiction. In particular, socially withdrawn athletes with rigid eating patterns and daily routines, and who exercise daily are at relatively high risk. By contrast, athletes who are more relaxed about their routines and diets are less likely to develop an addiction. This probably explains the findings on negative association with alcohol; it’s not that alcohol itself prevents an addiction but merely that athletes who are prepared to relax and let their hair down a bit are probably the personality types who are less likely to possess traits related to exercise addiction.

If you are a coach with athletes in your care, you can use this information to help identify those athletes who might be tempted to ignore the rule that ‘just because some is good, it doesn’t mean that more is better’! In particular, coaches should bear the risk of exercise addiction (along with other welfare factors) in mind when dealing with athletes who are reluctant to take rest days, seem excessively shy and withdrawn, and appear to have very rigid eating patterns.

If you’re an athlete reading this and it’s ringing a few alarm bells, don’t panic. There are a number of steps you can take to identify if you really are at risk and also practical strategies to reduce that risk. This article by Dr Adam Nicholls explains the background to exercise addiction in greater depth, and also provides a number of practical steps you can take!

References

1. Herz 2015; 40, 353–360. doi: 10.1007/s00059-015-4213-7
2. Prev. Med. Public Health 2013. 46, S12–S21
3. J. Sport Med 2005. 39, e30
4. Phys. Edu 2016. 6, 76–87
5. Behav. Addict 2017. 6, 74–83
6. Weight Disord. Stud. Anorexia Bulimia Obesity 2017. 23, 581–586
7. Behav. Rep 2016. 3, 33–37
8. Res. Theory 2014. 22, 431–437
9. Eat. Disord 2017. 5, 9
10. J. Eat. Disord 2018. 51, 352–357
11. New Zealand J. Psychiatry 2015 50, 322–333
12. Pharmacotherapy J. Hum. Pharmacol. Drug Therapy 2011. 31, 757–766
13. Front Sports Act Living. 2022 Aug 1;4:903777. doi: 10.3389/fspor.2022.903777