Skip to main content
SpringerLink
Log in

Military field training exercise with prolonged physical activity and sleep restriction causes hormonal imbalance in firefighter cadets

  • Original Article
  • Published:
Journal of Endocrinological Investigation Aims and scope Submit manuscript

Abstract

Purpose

To evaluate the impact of the “Search and rescue” field military training exercise (SR_FTX) on hormonal modulation and identify their possible correlation with physical and cognitive performance.

Methods

An observational (before and after) study was carried out, with male firefighters cadets (n = 42; age = 23[22;27] years) undergoing a nine-day military exercise (SR_FTX). The Countermovement jump (physical performance), the Stroop test (cognitive alertness), and blood tests for testosterone, cortisol, GH, and IGF-1 were applied. Wilcoxon for paired samples and Spearman’s correlation tests were used.

Results

Testosterone (751.10 [559.10;882.8] vs. 108.40 [80.12;156.40] ng/dL) and IGF-1 (217.5 [180;239.30] vs. 105 [93;129] ng/mL) significantly decreased while GH (0.10 [0.06;0.18] vs. 1.10 [0.58;2.28] ng/mL) and cortisol (9.60 [8.20;11.55] vs. 15.55 [12.28;18.98] ug/dL) significantly increased. Physical performance (31.2 [30.04;35.4] vs. 21.49 [19,02;23,59] cm) and cognitive alertness were significantly worse after SR_FTX (Congruent task: 1,78 (0183) vs. 1,56 (0185) response/s and incongruous task: 1,23 (0191) vs. 1,02 (0207) response/s). The physical performance showed a strong correlation with testosterone (rho = 0.694) and regular correlations with both IGF-1 (rho = 0.598) and cortisol (rho = − 0.580). The Stroop test presented weak correlations with GH (rho = − 0.350) and cortisol (rho = − 0.361).

Conclusion

SR_FTX negatively impacted hormonal modulation, physical and cognitive performance. These findings could help commanders decide to replace the employed firefighters in a real mission more frequently. Also, if the real scenario allows, they could think about providing better work conditions, such as improving caloric intake and rest periods, to preserve the military performance and health.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6

Similar content being viewed by others

Data availability

The datasets generated during and/or analyzed during the current study are available from the corresponding author on reasonable request.

References

  1. Academia de Bombeiro Militar Dom Pedro II (2016) Normas Gerais de Ação do Estágio Básico de Busca Resgate e Sobrevivência. Corpo de Bombeiros Militar do Estado do Rio de Janeiro. Boletim do Comando da ABMDPIInº172

  2. Drain JR, Groeller H, Burley SD, Nindl BC (2017) Hormonal response patterns are differentially influenced by physical conditioning programs during basic military training. J Sci Med Sport 20:98–103. https://doi.org/10.1016/j.jsams.2017.08.020

    Article  Google Scholar 

  3. Nindl BC, Barnes BR, Alemany JA et al (2007) Physiological consequences of US Army ranger training. Med Sci Sports Exerc 39(8):1380–1387. https://doi.org/10.1249/MSS.0b013e318067e2f7

    Article  Google Scholar 

  4. Nelson D L, Cox M M (2014) Princípios de Bioquímica de Lehninger. Artmed, Porto Alegre

  5. Church DD, Gwin JA, Wolfe RR et al (2019) Mitigation of muscle loss in stressed physiology: Military relevance. Nutrients 11(8):1703. https://doi.org/10.3390/nu11081703

    Article  CAS  Google Scholar 

  6. Pihlainen K, Kyröläinen H, Santtila M et al (2020) Effects of combined strength and endurance training on body composition, physical fitness, and serum hormones during a 6-Month crisis management operation. J Strength Cond Res. https://doi.org/10.1519/JSC.0000000000003902

    Article  Google Scholar 

  7. Henning PC, Park S, Kim JS (2011) Physiological decrements during sustained military operational stress. Mil Med 176(9):991–997. https://doi.org/10.7205/milmed-d-11-00053

    Article  Google Scholar 

  8. Nindl BC, Rarick KR, Castellani JW et al (2006) Altered secretion of growth hormone and luteinizing hormone after 84 h of sustained physical exertion superimposed on caloric and sleep restriction. J Appl Physiol 100(1):120–128. https://doi.org/10.1152/japplphysiol.01415.2004

    Article  CAS  Google Scholar 

  9. Conkright WR, Beckner ME, Sinnott AM et al (2021) Neuromuscular performance and hormonal responses to military operational stress in men and women. J Strength Cond Res 35(5):1296–1305. https://doi.org/10.1519/JSC.0000000000004013

    Article  Google Scholar 

  10. Lieberman HR, Bathalon GP, Falco CM et al (2005) Severe decrements in cognition function and mood induced by sleep loss, heat, dehydration, and undernutrition during simulated combat. Biol Psychiatry 57(4):422–429. https://doi.org/10.1016/j.biopsych.2004.11.014

    Article  Google Scholar 

  11. Hamarsland H, Paulsen G, Solberg PA et al (2018) Depressed physical performance outlasts hormonal disturbances after military training. Med Sci Sports Exerc 50(10):2076–2084. https://doi.org/10.1249/MSS.0000000000001681

    Article  Google Scholar 

  12. Brasil e Silva FB, Vaisman M, Ponce T et al (2022) A systematic review of hormone levels biomarkers of cellular injury and oxidative stress in multi stressor military field training exercises. Arch Endocrinol Metab. https://doi.org/10.20945/2359-3997000000443

    Article  Google Scholar 

  13. Brasil (2011) Tabela de Composição de Alimentos. NEPA/UNICAMP. https://www.nepa.unicamp.br/taco/contar/taco_4_edicao_ampliada_e_revisada.pdf?arquivo=taco_4_versao_ampliada_e_revisada.pdf. Accessed 10 May 2022

  14. Heavens KR, Kenefick RW, Caruso EM et al (2014) Validation of equations used to predict plasma osmolality in a healthy adult cohort. Am J Clin Nutr 100(5):1252–1256. https://doi.org/10.3945/ajcn.114.091009

    Article  CAS  Google Scholar 

  15. Holsgaard LA, Caserotti P, Puggaard L, Aagaard P (2007) Reproducibility and relationship of single-joint strength vs multi-joint strength and power in aging individuals. Scand J Med Sci Sports 17(1):43–53. https://doi.org/10.1111/j.1600-0838.2006.00560.x

    Article  Google Scholar 

  16. Balsalobre-Fernández C, Glaister M, Lockey RA (2015) The validity and reliability of an iPhone app for measuring vertical jump performance. J Sports Sci 33(15):1574–1579. https://doi.org/10.1080/02640414.2014.996184

    Article  Google Scholar 

  17. Jackson AS, Pollock ML (1985) Practical assessment of body composition. Physician Sportsmed 13(5):76–90. https://doi.org/10.1080/00913847.1985.11708790

    Article  CAS  Google Scholar 

  18. Silva VS, Vieira F (2020) International Society for the Advancement of Kinanthropometry (ISAK) Global: international accreditation scheme of the competent anthropometrist. Rev Bras Cineantropom Desempenho Hum. https://doi.org/10.1590/1980-0037.2020v22e70517

  19. Zimmermann N, Cardoso CO, Trentini CM et al (2015) Brazilian preliminary norms and investigation of age and education effects on the modified Wisconsin card sorting test, stroop color and word test and digit span test in adults. Dement Neuropsychol 9(2):120–127. https://doi.org/10.1590/1980-57642015DN92000006

    Article  Google Scholar 

  20. Callegari-Jacques SM (2003) Bioestatística: Princípios e aplicações. Artmed, Porto Alegre

  21. Ojanen T, Jalanko P, Kyröläinen H (2018) Physical fitness, hormonal, and immunological responses during prolonged military field training. Physiol Rep 6(17):13850. https://doi.org/10.14814/phy2.13850

    Article  CAS  Google Scholar 

  22. Henning PC, Scofield DE, Spiering BA et al (2014) Recovery of endocrine and inflammatory mediators following an extended energy deficit. J Clin Endocrinol Metab 99(3):956–964. https://doi.org/10.1210/jc.2013-3046

    Article  CAS  Google Scholar 

  23. Thomas DT, Erdman KA, Burke LM (2016) Position of the Academy of nutrition and dietetics, dietitians of Canada, and the American college of sports medicine: nutrition and athletic performance. J Acad Nutri Diet 116(3):501–528. https://doi.org/10.1016/j.jand.2015.12.006

    Article  Google Scholar 

  24. Casazza GA, Tovar AP, Richardson CE et al (2018) Energy availability, macronutrient intake, and nutritional supplementation for improving exercise performance in endurance athletes. Curr Sports Med Rep 17(6):215–223. https://doi.org/10.1249/JSR.0000000000000494

    Article  Google Scholar 

  25. Russell G, Lightman S (2019) The human stress response. Nat Rev Endocrinol 15(9):525–534. https://doi.org/10.1038/s41574-019-0228-0

    Article  Google Scholar 

  26. Nindl BC, Castellani JW, Young AJ et al (2003) Differential responses of IGF-I molecular complexes to military operational field training. J Appl Physiol 95(3):1083–1089. https://doi.org/10.1152/japplphysiol.01148.2002

    Article  CAS  Google Scholar 

  27. Friedl KE, Moore RJ, Hoyt RW et al (2000) Endocrine markers of semistarvation in healthy lean men in a multistressor environment. J Appl Physiol 88(5):1820–1830. https://doi.org/10.1152/jappl.2000.88.5.1820

    Article  CAS  Google Scholar 

  28. Szivak TK, Lee EC, Saenz C et al (2018) Adrenal stress and physical performance during Military survival training. Aerosp Med Hum Perform 89(2):99–107. https://doi.org/10.3357/AMHP.4831.2018

    Article  Google Scholar 

  29. Vikmoen O, Teien HK, Raustøl M et al (2020) Sex differences in the physiological response to a demanding military field exercise. Scand J Med Sci Sports 30(8):1348–1359. https://doi.org/10.1111/sms.13689

    Article  Google Scholar 

  30. Gomez-Merino D, Drogou C, Chennaoui M et al (2005) Effects of combined stress during intense training on cellular immunity, hormones and respiratory infections. NeuroImmunoModulation 12(3):164–172. https://doi.org/10.1159/000084849

    Article  CAS  Google Scholar 

  31. Beckner ME, Main L, Tait JL et al (2022) Circulating biomarkers associated with performance and resilience during military operational stress. Eur J Sport Sci 22(1):72–86. https://doi.org/10.1080/17461391.2021.1962983

    Article  Google Scholar 

  32. Vartanian O, Fraser B, Saunders D et al (2018) Changes in mood, fatigue, sleep, cognitive performance and stress hormones among instructors conducting stressful military captivity survival training. Physiol Behav 194:137–143. https://doi.org/10.1016/j.physbeh.2018.05.008

    Article  CAS  Google Scholar 

  33. Booth CK, Probert B, Forbes-Ewan C, Coad RA (2006) Australian army recruits in training display symptoms of overtraining. Mil Med 171(11):1059–1064. https://doi.org/10.7205/milmed.171.11.1059

    Article  Google Scholar 

  34. Lieberman HR, Bathalon GP, Falco CM et al (2005) The fog of war: decrements in cognitive performance and mood associated with combat-like stress. Aviat Space Environ Med 76(7 Suppl):C7–C14 (PMID: 16018323)

    Google Scholar 

  35. Lieberman HR, Farina EK, Caldwell J et al (2016) Cognitive function, stress hormones, heart rate and nutritional status during simulated captivity in military survival training. Physiol Behav 165:86–97. https://doi.org/10.1016/j.physbeh.2016.06.037

    Article  CAS  Google Scholar 

  36. Nyberg F, Hallberg M (2013) Growth hormone and cognitive function. Nat Rev Endocrinol 9(6):357–365. https://doi.org/10.1038/nrendo.2013.78

    Article  CAS  Google Scholar 

  37. Hickey JP, Donne B, O’Brien D (2012) Effects of an eight week military training program on aerobic indices and psychomotor function. J R Army Med Corps 158(1):41–46. https://doi.org/10.1136/jramc-158-01-11

    Article  CAS  Google Scholar 

Download references

Acknowledgements

The authors would like to thank all the Commanders of the Dom Pedro II Military Firefighter Academy (Academia de Bombeiro Militar Dom Pedro II—ABMDP II). This work was supported by Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ)–“Pesquisador do Nosso Estado” (Researcher from our state) grant–and also by Conselho Nacional de Pesquisa (CNPq)–“Pesquisador Senior” (Senior researcher) grant and by the Coordination for the impovement of higher education (CAPES) of the ministry of education (MEC)–Brazil 00.889.834/0001-08 and 88882.424876/2019-01.

Funding

This work was supported by Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ)–“Researcher from our state”. Conselho Nacional de Pesquisa (CNPq)–“Senior researcher”. Coordination for the improvement of higher education (CAPES) of the ministry of education (MEC)–Brazil 00.889.834/0001-08 and 88882.424876/2019-01.

Author information

Authors and Affiliations

  1. Academia de Bombeiro Militar Dom Pedro II (Dom Pedro II Military Firefighter Academy-ABMDPII), Rio de Janeiro, RJ, 21660-001, Brazil

    T. Ponce & T. Ramos de Barros

  2. Escola de Educação Física do Exército (Physical Education College of the Brazilian Army–EsEFEx), Rio de Janeiro, RJ, 22291-090, Brazil

    M. R. M. Mainenti

  3. Escola de Educação Física E Desportos (Physical Education and Sports College of the Federal University of Rio de Janeiro–EEFD/UFRJ), Rio de Janeiro, RJ, 21941-599, Brazil

    T. Ponce, E. L. Cardoso, T. Ramos de Barros & V. Pinto Salerno

  4. Faculdade de Medicina–Endocrinologia (Medicine Collegof the Federal University of Rio de Janeiro–FM-UFRJ), Rio de Janeiro, RJ, 21941-617, Brazil

    T. Ponce, E. L. Cardoso & M. Vaisman

Authors
  1. T. Ponce
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. M. R. M. Mainenti
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. E. L. Cardoso
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. T. Ramos de Barros
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. V. Pinto Salerno
    View author publications

    You can also search for this author in PubMed Google Scholar

  6. M. Vaisman
    View author publications

    You can also search for this author in PubMed Google Scholar

Contributions

TP, MRMM, TB, VS, MV participated in study design. TP and MRMM wrote the first draft of the manuscript. TP, ELC, TB and MRMM participated in data collection and analysis. All authors participated in manuscript preparation and approved its final version.

Corresponding author

Correspondence to T. Ponce.

Ethics declarations

Conflict of interest

All authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Research involving human participates and/or animals

This study was performed in line with the principles of the Declaration of Helsinki. Approval was granted by the Ethics Committee of Centro Universitario Augusto Motta (CAAE: 73367317.2.0000.5235).

Informed consent

Informed consent was obtained from all individual participants included in the study.

Additional information

Publisher's Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Springer Nature or its licensor holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Ponce, T., Mainenti, M.R.M., Cardoso, E.L. et al. Military field training exercise with prolonged physical activity and sleep restriction causes hormonal imbalance in firefighter cadets. J Endocrinol Invest 46, 381–391 (2023). https://doi.org/10.1007/s40618-022-01913-4

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s40618-022-01913-4

Keywords

Search

Navigation