Changes in body mass and urinary biomarkers after a long-lasting combat search and rescue military exercise performed in a tropical region

Abstract

The study aimed to evaluate body mass changes and urine biomarker responses during a Combat Search and Rescue (CSAR) military exercise performed in a tropical region. Ten urinary biomarkers were analyzed via dipstick urinalysis to assess the physiological strain and the potential health risks associated with this exercise. Body mass and urine samples were obtained from 151 male cadets ([21.3 ​± ​1.6] year-old; height [177.2 ​± ​4.1] ​cm) before and after completing the efforts of a CSAR exercise that lasted approximately 10 ​hour (h). Body mass significantly decreased (p ​< ​0.05) by more than 3% immediately post-exercise (from [75.0 ​± ​9.85] kg to [72.6 ​± ​9.6] ​kg), returning to pre-exercise levels within 14 and 38 ​h after the complen. Interestingly, urine specific gravity (USG) paralleled the changes in body mass and exhibited a significant increase immediately after the exercise. Similar patterns of significant alterations were observed in urine acidity, ketonuria, bilirubinuria, and hematuria, mirroring the time course of changes in USG. The other evaluated urine variables did not show significant changes. The reduction in body mass was significantly correlated with changes in USG, ketonuria, bilirubinuria and proteinuria after the military exercise. In summary, cadets engaged in the CSAR military exercise experienced physiologically meaningful dehydration and exhibited indirect markers of cell damage immediately after the exercise. However, these changes were spontaneously resolved within 14 ​h post-task. Monitoring selected non-invasive biomarkers could aid in managing performance and health risks during arduous military training.

Keywords

Cadets / Military health / Health monitoring / Military training / Urine analysis

CRediT authorship contribution statement

Diego Fortes de Souza Salgueiro: Writing - review & editing, Writing - original draft, Project administration, Methodology, Formal analysis, Conceptualization. Tiago Rezende Figueira: Writing - review & editing, Writing - original draft, Methodology, Formal analysis, Data curation. Orival Andries Júnior: Writing - review & editing, Writing -original draft, Project administration, Formal analysis, Conceptualization.

Ethical approval

This study was reviewed and approved by the Human Ethics Com-mittee of authors' Institution, the State University of Campinas, under the protocol numbers 3045772/2018 and 3735988/2019. All participants gave informed consent before their enrollment in the study. The study was implemented in accordance with international ethical standards,16 and the Declaration of Helsinki.17 In addition, the authorities of the Air Force Academy adhered to Resolution 466/12 from the Brazilian Na-tional Health Council and approved all procedures prior to their commencement, including access to the institution's databases.

Funding

This study was financed in part by the Coordenaç~ao de Aperfeiçoa-mento de Pessoal de Nível Superior - Brasil (CAPES)-Finance Code 001.

Declaration of competing interest

The authors declare that they have no direct or indirect interests that could have appeared to influence the conduction and work reported in this paper.

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