Wilson Patrick B, Winter Ian P
Human Performance Laboratory, School of Exercise Science, Old Dominion University, Norfolk, Virginia, USA.
Transl Sports Med. 2024 Dec 9;2024:8827027. doi: 10.1155/tsm2/8827027. eCollection 2024.
Urine specific gravity (USG) is a commonly used assessment method to estimate the prevalence of hypohydration, typically based on a common threshold of ≥ 1.020. Some research has shown that USG can vary based on body size and composition, but the evidence to date is limited. This review examined whether an association between fat-free mass (FFM), a component of body composition, and USG could be detected among published articles that have reported these variables in athletes and physically active individuals. By searching Google Scholar, the authors identified a large number of published articles ( = 161) reporting anthropometrics and USG. Only articles reporting data on adult samples of athletes or physically active individuals were included. Given differences in body composition and FFM between men and women, articles that did not report data separately for each sex were excluded. Spearman's rank correlation coefficient () was used to assess the association between variables. In men, FFM showed a significant, weak-sized positive association with USG ( = 0.36, < 0.001). Among women, FFM showed a significant, moderate-sized positive association with USG ( = 0.57, =0.006). When results were combined independent of sex, the association between FFM and USG remained significant ( = 0.38, < 0.001). Athletes with larger amounts of FFM are more likely to have elevated USG. Protein and muscle metabolites such as creatinine, urea, and uric acid likely play some role in the observed relationships. If USG continues to be utilized in sport settings, more research is needed to determine if development of FFM-specific USG thresholds may be more appropriate for determining hydration status.
尿比重（USG）是一种常用的评估方法，用于估计脱水的发生率，通常基于≥1.020这一常见阈值。一些研究表明，尿比重可能因体型和身体成分而异，但迄今为止证据有限。本综述考察了在已发表的、报道了运动员和身体活跃个体中这些变量的文章中，能否检测到身体成分的一个组成部分——去脂体重（FFM）与尿比重之间的关联。通过在谷歌学术上搜索，作者识别出大量发表的文章（n = 161），这些文章报道了人体测量学和尿比重。仅纳入了报道运动员或身体活跃个体成年样本数据的文章。鉴于男性和女性在身体成分和去脂体重方面存在差异，未分别报告各性别数据的文章被排除。采用斯皮尔曼等级相关系数（r）来评估变量之间的关联。在男性中，去脂体重与尿比重呈显著的、弱强度正相关（r = 0.36，P < 0.001）。在女性中，去脂体重与尿比重呈显著的、中等强度正相关（r = 0.57，P = 0.006）。当不考虑性别合并结果时，去脂体重与尿比重之间的关联仍然显著（r = 0.38，P < 0.001）。去脂体重较高的运动员更有可能尿比重升高。蛋白质以及肌酐、尿素和尿酸等肌肉代谢产物可能在观察到的这些关系中发挥了一定作用。如果尿比重继续在体育环境中使用，需要更多研究来确定是否制定特定去脂体重的尿比重阈值可能更适合用于确定水合状态。
