Risk factors for athletes

Although moderate or vigorous-intensity aerobic activity is important in the prevention of and recovery from mental and physical health problems, when performed more intensely at ‘professional/elite’ levels, physical activity can compromise health. ^{Reference Schwenk1,Reference Peluso and de Andrade5} Beyond the national prestige, fame and glory of Olympic success lies the darker side of overexposure to elite sport such as overtraining, injury, burnout, increased risk for sudden cardiac death and other non-cardiovascular conditions such as respiratory symptoms, iron deficiency, increased incidence of allergies, immunological suppression and infection, gastrointestinal symptoms, diabetes mellitus and eating disorders. ^{Reference Ljungqvist, Jenoure, Engebretsen, Alonso, Bahr and Clough6}

Athletes may also be vulnerable to mental illness for several reasons. First, the social world of many organised elite sports is one that requires investments of time and energy, often resulting in a loss of personal autonomy and disempowerment for athletes. ^{Reference Cresswell and Eklund7} The elite-sport environment can result in ‘identity-foreclosure’ leaving athletes few other avenues through which to shape and reflect personality. ^{Reference Cresswell and Eklund7} High athletic identity has been linked to psychological distress when this function of identity is removed, and to overtraining and athlete burnout. ^{Reference Cresswell and Eklund7} The latter conditions strongly correlate with affective disorders such as major depressive disorder. ^{Reference Peluso and de Andrade5,Reference Cresswell and Eklund7} Moreover, injury, competitive failure, ageing, retirement from sport and other psychosocial stressors, precipitate depression in athletes. ^{Reference Reardon and Factor8} In addition, the literature on elite sport indicates a range of other vulnerabilities such as disordered eating ^{Reference Sundgot-Borgen and Torstveit9} and risk-taking behaviours among athletes such as hazardous drinking, driving while intoxicated and unprotected sex. ^{Reference Lisha and Sussman10}

The prevalence of overtraining in elite athletes has been reported at between 20 and 60%, with distance runners most severely affected. ^{Reference Peluso and de Andrade5} Burnout, the most extreme end of the overtraining continuum, has been reported in approximately 10% of elite athletes. ^{Reference Cresswell and Eklund7} Moreover, a recent review of eating disorders among those participating in high-intensity sports, reported a prevalence of 17.2% for males and 32% for females. ^{Reference Sundgot-Borgen and Torstveit9} Other studies have reported eating disorders in women athletes to be as high as 60%, with athletes found to be in more severe stages of the disorder than controls. ^{Reference Reardon and Factor8} Compounding this, the injury experience of an elite athlete has been likened to the grief process observed following bereavement, with an estimated 10–20% of athletes warranting clinical intervention, with suicide a cause of concern. ^{Reference Walker, Thatcher and Lavallee11} A dose–response relationship exists between physical activity and the likelihood of injury; again, with elite athletes at most risk.

The appendix summarises a growing body of evidence pointing to both the positive and negative health outcomes of elite sport. However, despite a number of high-profile breakdowns and tragedies among athletes there remains a tendency among sports governing bodies and officials to downplay or ignore the significance of psychiatric symptoms among this population. ^{Reference Reardon and Factor8} Schwenk's work indicates how the current approach to mental illness in athletes is ‘fraught with stigmatisation, denial, and dichotomous paradigms of “psychological” versus “physical” disease, which are inaccurate, unhelpful and deprive the athlete of effective care’. ^{Reference Schwenk1} This scenario is in no way helped by the unusual clinical environment whereby the traditional relationship between doctor and patient it distorted or absent. Doctors working within the sporting environment are frequently under intense pressure from management, coaches, trainers and agents to improve performance in the short term and are therefore faced with a myriad of ethical dilemmas that compromise the well-being and treatment of the athlete. ^{Reference Devitt and McCarthy12}

Appendix Positive and negative effects of elite sport on health outcomes Adapted from Hamer et al, ^{Reference Hamer, Stamatakis and Steptoe4} Lisha & Sussman, ^{Reference Lisha and Sussman10} Walker et al, ^{Reference Walker, Thatcher and Lavallee11} Smith ^{Reference Smith13} and Maffulli et al ^{Reference Maffulli, Giuseppe Longo, Gougoulias, Caine and Denaro14}

Positive effects
Neurological	Mental	Physical
↑ neurological functioning (central norepinephrine neurotransmission, secretion of atrial natriuretic peptide, metabolism and beta-endorphins, availability of brain neurotransmitters dopamine, serotonin and noradrenaline, enhanced cognitive functioning and brain plasticity) Increases peripheral catecholamine plasma levels which are associated with learning and memory improvements Can reverse the effects of stress, depression and ageing on neurotrophic expression and neurogenesis in the brain	↓ incidence of dysthemic (mood and chronic depressive) disorders Provides immediate psychological benefits (↑ mood, ↑ level of brainderived neurotrophic factor acting just like a regular antidepressive drug) ↓ emotional distress and anxiety Increased self-efficacy, mastery and self-concept	↓ incidence of somatoform (physical symptoms of mental disorders) ↓ risk of chronic disease and comorbid mental disorders, delaying the onset of neurodegenerative processes (↑ circulation of pro-inflammatory cytokines that is normally up-regulated during a stress response that over time can increase immune system threshold for stress)
Negative effects
Neurological	Mental	Physical
Overtraining: body's up-regulation of acute inflammation resulting in the production of elevated levels of cytokines and cortisol levels	Psychological impact of injury (e.g. depression, low motivation, isolation, bereavement responses of denial and anger, loss of identity, loss of confidence, performance decrement) Disordered eating: anorexia nervosa, bulimia and body dysmorphia Burnout: # mood and self-esteem, loss of confidence, exhaustion, depression/helplessness, withdrawal	Injury incidence: resulting in limb deformities, leg length discrepancy, susceptibility to growth plate injury, limited thermoregulatory capacity and maturity associated variation in young elite performers; increased risk of developing osteoarthritis and spine pathologies in former athletes Overtraining: altered immune function including susceptibility to colds, flus and infection, gastrointestinal disturbances, headaches and muscle aches13 Athlete burnout – physical exhaustion, reduced performance accomplishment and sporting devaluation that serves to compromise future physical activity involvement. Symptoms include disrupted sleep, ↑ muscle soreness, chronic fatigue, ↓ incidence of injury/illness, and # aerobic power Risk-taking behaviours of sports people (e.g. hazardous drinking, driving while intoxicated, having unprotected sex and antisocial behaviour) Increased risk for sudden cardiac death, respiratory symptoms, iron deficiency, increased incidence of allergies, immunological suppression and infection, gastrointestinal symptoms, diabetes mellitus