The term Relative Energy Deficiency in Sport was introduced by the International Olympic Committee in 2014. It refers to the potential health and performance consequences of inadequate energy for sport, emphasizing that there are consequences of low energy availability (EA; typically defined as <30 kcal·kg−1 fat-free mass·day−1) beyond the important and well-established female athlete triad, and that low EA affects populations other than women. As the prevalence and consequences of Relative Energy Deficiency in Sport become more apparent, it is important to understand the current knowledge of the hormonal changes that occur with decreased EA. This paper highlights endocrine changes that have been observed in female and male athletes with low EA. Where studies are not available in athletes, results of studies in low EA states, such as anorexia nervosa, are included. Dietary intake/appetite-regulating hormones, insulin and other glucose-regulating hormones, growth hormone and insulin-like growth factor 1, thyroid hormones, cortisol, and gonadal hormones are all discussed. The effects of low EA on body composition, metabolic rate, and bone in female and male athletes are presented, and we identify future directions to address knowledge gaps specific to athletes.
Kirsty J. Elliott-Sale, Adam S. Tenforde, Allyson L. Parziale, Bryan Holtzman and Kathryn E. Ackerman
Bryan Holtzman, Adam S. Tenforde, Allyson L. Parziale and Kathryn E. Ackerman
This study’s objective was to identify differences in risk for low energy availability and athletic clearance level by comparing scores on Female Athlete Triad Cumulative Risk Assessment (Triad CRA) and Relative Energy Deficiency in Sport Clinical Assessment Tool (RED-S CAT). A total of 1,000 female athletes aged 15–30 years participating in ≥4 hr of physical activity/week for the previous ≥6 months completed an extensive survey assessing health, athletic history, family disease history, and specific Triad/RED-S risk factors. Retrospective chart review ascertained laboratory and bone mineral density measures. Triad CRA and RED-S CAT were used to assign each athlete’s risk level (low, moderate, and high), and case-by-case comparison measured the level of agreement between the tools. We hypothesized that the tools would generally agree on low-risk athletes and that the tools would be less aligned in the specific elevated risk level (moderate or high). Most of the sample was assigned moderate or high risk for Triad CRA and RED-S CAT (Triad: 54.7% moderate and 7.9% high; RED-S: 63.2% moderate and 33.0% high). The tools agreed on risk for 55.5% of athletes. Agreement increased to 64.3% when only athletes with bone mineral density measurements were considered. In conclusion, Triad CRA and RED-S CAT provide consensus on the majority of athletes at elevated (moderate or high) risk for low energy availability, but have less agreement on the specific risk level assigned.
Louise M. Burke, Graeme L. Close, Bronwen Lundy, Martin Mooses, James P. Morton and Adam S. Tenforde
Low energy availability (LEA) is a key element of the Female Athlete Triad. Causes of LEA include failure to match high exercise energy expenditure (unintentional) or pathological behaviors of disordered eating (compulsive) and overzealous weight control programs (misguided but intentional). Recognition of such scenarios in male athletes contributed to the pronouncement of the more inclusive Relative Energy Deficiency in Sport (RED-S) syndrome. This commentary describes the insights and experience of the current group of authors around the apparently heightened risk of LEA in some populations of male athletes: road cyclists, rowers (lightweight and open weight), athletes in combat sports, distance runners, and jockeys. The frequency, duration, and magnitude of the LEA state appear to vary between populations. Common risk factors include cyclical management of challenging body mass and composition targets (including “making weight”) and the high energy cost of some training programs or events that is not easily matched by energy intake. However, additional factors such as food insecurity and lack of finances may also contribute to impaired nutrition in some populations. Collectively, these insights substantiate the concept of RED-S in male athletes and suggest that a specific understanding of a sport, subpopulation, or culture may identify a complex series of factors that can contribute to LEA and the type and severity of its outcomes. This commentary provides a perspective on the range of risk factors that should be addressed in future surveys of RED-S in athletic populations and targeted for specific investigation and modification.