A study for markers of low energy availability in athletes: a meta-analysis of cross-sectional studies.

PURPOSE: When low energy availability (LEA) falls below threshold levels, it is associated with declines in physiological functions such as bone health and endocrine function. This is associated with diminished physical capabilities and impaired performance in athletes. Therefore, this study aimed to conduct a meta-analysis examining body composition and hormonal status in athletes according to low energy availability (LEA) status, with the aim of identifying physiological characteristics associated with energy imbalance. METHOD: To compare LEA and normal energy availability (NEA), a literature search was conducted using keywords related to body composition and hormones by limiting it to studies from January 2007 to July 2023 in Web of Science, Scopus, SPORTDiscus, PubMed, Google Scholar, Cochrane Library, and ScienceDirect databases. As a result, 11 studies were finally selected. RESULT: A total of 11 studies met the inclusion criteria for this meta-analysis, encompassing 1006 athletes (471 females [49.4%] and 535 males [50.6%]), of whom 509 (50.6%) were identified as having LEA. Athletes with LEA tended to have lower weight, body mass index (BMI), and total body BMD Z-score. Furthermore, several physiological markers were lower, while cortisol levels were higher and leptin levels did not differ significantly. CONCLUSION: The results suggest that athletes with LEA may experience impairments in physiological functions, including alterations in gonadal hormones and bone mineral density markers. This study systematically examined endocrine responses in athletes with low energy availability. These findings suggest that LEA is associated with adverse health outcomes in athletes.