L'acclimatation à la chaleur ne protège pas les hommes entraînés contre les déficiences induites par l'hyperthermie dans l'exécution de tâches complexes

Aperçu: G.M.

Cette étude a évalué si l'adaptation au stress thermique environnemental peut contrecarrer les effets négatifs de l'hyperthermie sur les performances motrices complexes. 

Treize hommes en bonne santé et entraînés ont effectué 28 jours d'acclimatation à la chaleur avec 1 h d'exercice quotidien d'exposition à la chaleur ambiante (39,4 ± 0,3 °C et 27,0 ± 1,0 % d'humidité relative). Après une familiarisation complète, les participants ont effectué des tests moteurs et cognitifs avant l'acclimatation, ainsi qu'après 14 et 28 jours d'entraînement sous la chaleur. Aux trois occasions, les participants ont été testés, au départ (après environ 15 minutes d'exposition à la chaleur passive) et à la suite d'une hyperthermie induite par l'exercice qui a provoqué une augmentation de la température centrale de 2,8 ± 0,1 °C (similaire d'un jour à l'autre). 

Les résultats aux tests dominés par la cognition et les performances motrices ont été maintenus pendant l'exposition passive à la chaleur (aucune réduction ni différence entre les jours 0, 14 et 28 par rapport aux conditions fraîches). En revanche, les performances des tâches motrices complexes étaient significativement réduites dans des conditions hyperthermiques de 9,4 ± 3,4 % au jour 0 ; 15,1 ± 5,0 % au jour 14 et 13,0 ± 4,8 % au jour 28 (tous p < 0,05 par rapport à la ligne de base mais pas différents d'un jour à l'autre). 

Ces résultats nous permettent de conclure que l'acclimatation à la chaleur ne peut pas protéger les hommes entraînés contre les effets négatifs de l'hyperthermie lorsqu'ils effectuent des tâches complexes reposant sur une combinaison de performances cognitives et de fonctions motrices.

. 2019 Feb 28;16(5):716.  doi: 10.3390/ijerph16050716.

Heat Acclimation Does Not Protect Trained Males from Hyperthermia-Induced Impairments in Complex Task Performance

Jacob F Piil  ¹ , Chris J Mikkelsen  ² , Nicklas Junge  ³ , Nathan B Morris  ⁴ , Lars Nybo  ⁵

Affiliations

• PMID: 30823366
• PMCID: PMC6427404
• DOI: 10.3390/ijerph16050716

Free PMC article

Abstract

This study evaluated if adaptation to environmental heat stress can counteract the negative effects of hyperthermia on complex motor performance. Thirteen healthy, trained males completed 28 days of heat acclimation with 1 h daily exercise exposure to environmental heat (39.4 ± 0.3 °C and 27.0 ± 1.0% relative humidity). Following comprehensive familiarization, the participants completed motor-cognitive testing before acclimation, as well as after 14 and 28 days of training in the heat. On all three occasions, the participants were tested, at baseline (after ~15 min passive heat exposure) and following exercise-induced hyperthermia which provoked an increase in core temperature of 2.8 ± 0.1 °C (similar across days). Both cognitively dominated test scores and motor performance were maintained during passive heat exposure (no reduction or difference between day 0, 14, and 28 compared to cool conditions). In contrast, complex motor task performance was significantly reduced in hyperthermic conditions by 9.4 ± 3.4% at day 0; 15.1 ± 5.0% at day 14, and 13.0 ± 4.8% at day 28 (all p < 0.05 compared to baseline but not different across days). These results let us conclude that heat acclimation cannot protect trained males from being negatively affected by hyperthermia when they perform complex tasks relying on a combination of cognitive performance and motor function.

Keywords: core temperature; heat stress; hyperthermia; mathematics; motor performance; task complexity; visuo-motor tracking.

Conflict of interest statement

The authors declare no conflict of interest.

Figures

Figure 1

Thermal discomfort vs. exercise time…

Figure 2

Complex motor task performance score.…

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References

1. 1. Piil J.F., Lundbye-Jensen J., Trangmar S.J., Nybo L. Performance in complex motor tasks deteriorates in hyperthermic humans. Temperature. 2017;4:420–428. doi: 10.1080/23328940.2017.1368877. - DOI - PMC - PubMed
2. 1. Taylor L., Watkins S.L., Marshall H., Dascombe B.J., Foster J. The Impact of Different Environmental Conditions on Cognitive Function: A Focused Review. Front. Physiol. 2015;6:372. doi: 10.3389/fphys.2015.00372. - DOI - PMC - PubMed
3. 1. Hancock P.A. Task categorization and the limits of human performance in extreme heat. Aviat. Space Environ. Med. 1982;53:778–784. - PubMed
4. 1. Gaoua N., Racinais S., Grantham J., El Massioui F. Alterations in cognitive performance during passive hyperthermia are task dependent. Int. J. Hyperthermia. 2011;27:1–9. doi: 10.3109/02656736.2010.516305. - DOI - PMC - PubMed
5. 1. Todd G., Butler J.E., Taylor J.L., Gandevia S.C. Hyperthermia: A failure of the motor cortex and the muscle. J. Physiol. 2005;563:621–631. doi: 10.1113/jphysiol.2004.077115. - DOI - PMC - PubMed
6. 1. Hancock P.A., Vasmatzidis I. Effects of heat stress on cognitive performance: The current state of knowledge. Int. J. Hyperthermia. 2003;19:355–372. doi: 10.1080/0265673021000054630. - DOI - PubMed
7. 1. Nybo L. CNS fatigue provoked by prolonged exercise in the heat. Front. Biosci. (Elite Ed.) 2010;2:779–792. doi: 10.2741/e138. - DOI - PubMed
8. 1. Périard J.D., Racinais S., Sawka M.N. Adaptations and mechanisms of human heat acclimation: Applications for competitive athletes and sports: Adaptations and mechanisms of heat acclimation. Scand. J. Med. Sci. Sports. 2015;25:20–38. doi: 10.1111/sms.12408. - DOI - PubMed
9. 1. Daanen H.A.M., Racinais S., Périard J.D. Heat Acclimation Decay and Re-Induction: A Systematic Review and Meta-Analysis. Sports Med. 2018;48:409–430. doi: 10.1007/s40279-017-0808-x. - DOI - PMC - PubMed
10. 1. Junge N., Jorgensen R., Flouris A.D., Nybo L. Prolonged self-paced exercise in the heat—Environmental factors affecting performance. Temperature. 2016;3:539–548. doi: 10.1080/23328940.2016.1216257. - DOI - PMC - PubMed
11. 1. Nybo L., Rasmussen P., Sawka M.N. Performance in the heat-physiological factors of importance for hyperthermia-induced fatigue. Compr. Physiol. 2014;4:657–689. - PubMed
12. 1. Hancock P.A., Ross J.M., Szalma J.L. A Meta-Analysis of Performance Response Under Thermal Stressors. Hum. Factors. 2007;49:851–877. doi: 10.1518/001872007X230226. - DOI - PubMed
13. 1. Flouris A.D., Dinas P.C., Ioannou L.G., Nybo L., Havenith G., Kenny G.P., Kjellstrom T. Workers’ health and productivity under occupational heat strain: A systematic review and meta-analysis. Lancet Planet. Health. 2018;2:e521–e531. doi: 10.1016/S2542-5196(18)30237-7. - DOI - PubMed
14. 1. Binazzi A., Levi M., Bonafede M., Bugani M., Messeri A., Morabito M., Marinaccio A., Baldasseroni A. Evaluation of the impact of heat stress on the occurrence of occupational injuries: Meta-analysis of observational studies. Am. J. Ind. Med. 2019;62:233–243. doi: 10.1002/ajim.22946. - DOI - PubMed
15. 1. Zander K.K., Botzen W.J.W., Oppermann E., Kjellstrom T., Garnett S.T. Heat stress causes substantial labour productivity loss in Australia. Nat. Clim. Chang. 2015;5:647–651. doi: 10.1038/nclimate2623. - DOI
16. 1. Kjellstrom T. Impact of Climate Conditions on Occupational Health and Related Economic Losses: A New Feature of Global and Urban Health in the Context of Climate Change. Asia Pac. J. Public Health. 2016;28:28S–37S. doi: 10.1177/1010539514568711. - DOI - PubMed
17. 1. Kjellstrom T., Holmer I., Lemke B. Workplace heat stress, health and productivity—An increasing challenge for low and middle-income countries during climate change. Glob. Health Action. 2009;2:2047. doi: 10.3402/gha.v2i0.2047. - DOI - PMC - PubMed
18. 1. Mora C., Dousset B., Caldwell I.R., Powell F.E., Geronimo R.C., Bielecki C.R., Counsell C.W.W., Dietrich B.S., Johnston E.T., Louis L.V., et al. Global risk of deadly heat. Nat. Clim. Change. 2017;7:501–506. doi: 10.1038/nclimate3322. - DOI
19. 1. Karlsen A., Racinais S., Jensen M.V., Norgaard S.J., Bonne T., Nybo L. Heat acclimatization does not improve VO2max or cycling performance in a cool climate in trained cyclists. Scand. J. Med. Sci. Sports. 2015;25(Suppl. 1):269–276. doi: 10.1111/sms.12409. - DOI - PubMed
20. 1. Gaoua N., Herrera C.P., Périard J.D., El Massioui F., Racinais S. Effect of Passive Hyperthermia on Working Memory Resources during Simple and Complex Cognitive Tasks. Front. Psychol. 2018;8:2290. doi: 10.3389/fpsyg.2017.02290. - DOI - PMC - PubMed
21. 1. Curley M.D., Hawkins R.N. Cognitive performance during a heat acclimatization regimen. Aviat. Space Environ. Med. 1983;54:709–713. - PubMed
22. 1. Radakovic S.S., Maric J., Surbatovic M., Radjen S., Stefanova E., Stankovic N., Filipovic N. Effects of Acclimation on Cognitive Performance in Soldiers during Exertional Heat Stress. Mil. Med. 2007;172:133–136. doi: 10.7205/MILMED.172.2.133. - DOI - PubMed
23. 1. Tamm M., Jakobson A., Havik M., Timpmann S., Burk A., Ööpik V., Allik J., Kreegipuu K. Effects of heat acclimation on time perception. Int. J. Psychophysiol. 2015;95:261–269. doi: 10.1016/j.ijpsycho.2014.11.004. - DOI - PubMed
24. 1. Brazaitis M., Skurvydas A. Heat acclimation does not reduce the impact of hyperthermia on central fatigue. Eur. J. Appl. Physiol. 2010;109:771–778. doi: 10.1007/s00421-010-1429-3. - DOI - PubMed
25. 1. Racinais S., Wilson M.G., Gaoua N., Périard J.D. Heat acclimation has a protective effect on the central but not peripheral nervous system. J. Appl. Physiol. 2017;123:816–824. doi: 10.1152/japplphysiol.00430.2017. - DOI - PubMed
26. 1. Sahu S., Sett M., Kjellstrom T. Heat exposure, cardiovascular stress and work productivity in rice harvesters in India: Implications for a climate change future. Ind. Health. 2013;51:424–431. doi: 10.2486/indhealth.2013-0006. - DOI - PubMed
27. 1. Ioannou L.G., Tsoutsoubi L., Samoutis G., Bogataj L.K., Kenny G.P., Nybo L., Kjellstrom T., Flouris A.D. Time-motion analysis as a novel approach for evaluating the impact of environmental heat exposure on labor loss in agriculture workers. Temperature. 2017;4:330–340. doi: 10.1080/23328940.2017.1338210. - DOI - PMC - PubMed
28. 1. Piil J.F., Lundbye-Jensen J., Christiansen L., Ioannou L., Tsoutsoubi L., Dallas C.N., Mantzios K., Flouris A.D., Nybo L. High prevalence of hypohydration in occupations with heat stress—Perspectives for performance in combined cognitive and motor tasks. PLoS ONE. 2018;13:e0205321. doi: 10.1371/journal.pone.0205321. - DOI - PMC - PubMed
29. 1. Lorenzo S., Halliwill J.R., Sawka M.N., Minson C.T. Heat acclimation improves exercise performance. J. Appl. Physiol. 2010;109:1140–1147. doi: 10.1152/japplphysiol.00495.2010. - DOI - PMC - PubMed
30. 1. Nielsen B., Hales J.R., Strange S., Christensen N.J., Warberg J., Saltin B. Human circulatory and thermoregulatory adaptations with heat acclimation and exercise in a hot, dry environment. J. Physiol. 1993;460:467–485. doi: 10.1113/jphysiol.1993.sp019482. - DOI - PMC - PubMed
31. 1. Atkinson G., Nevill A.M. Statistical Methods for Assessing Measurement Error (Reliability) in Variables Relevant to Sports Medicine. Sports Med. 1998;26:217–238. doi: 10.2165/00007256-199826040-00002. - DOI - PubMed
32. 1. Cohen J. A power primer. Psychol. Bull. 1992;112:155–159. doi: 10.1037/0033-2909.112.1.155. - DOI - PubMed
33. 1. Tawatsupa B., Yiengprugsawan V., Kjellstrom T., Berecki-Gisolf J., Seubsman S.A., Sleigh A. Association between Heat Stress and Occupational Injury among Thai Workers: Findings of the Thai Cohort Study. Ind. Health. 2013;51:34–46. doi: 10.2486/indhealth.2012-0138. - DOI - PubMed
34. 1. Ramsey J.D., Burfurd C.L., Beshir M.Y., Jensen R.C. Effects of Workplace Thermal Conditions on Safe Work Behavior. J. Safety Res. 1983;14:105–114. doi: 10.1016/0022-4375(83)90021-X. - DOI
35. 1. Hancock P.A., Vasmatzidis I. Human occupational and performance limits under stress: The thermal environment as a prototypical example. Ergonomics. 1998;41:1169–1191. doi: 10.1080/001401398186469. - DOI - PubMed
36. 1. Racinais S., Gaoua N., Grantham J. Hyperthermia impairs short-term memory and peripheral motor drive transmission. J. Physiol. 2008;586:4751–4762. doi: 10.1113/jphysiol.2008.157420. - DOI - PMC - PubMed
37. 1. Malcolm R.A., Cooper S., Folland J.P., Tyler C.J., Sunderland C. Passive Heat Exposure Alters Perception and Executive Function. Front. Physiol. 2018;9:585. doi: 10.3389/fphys.2018.00585. - DOI - PMC - PubMed
38. 1. Périard J.D., Travers G.J.S., Racinais S., Sawka M.N. Cardiovascular adaptations supporting human exercise-heat acclimation. Auton. Neurosci. 2016;196:52–62. doi: 10.1016/j.autneu.2016.02.002. - DOI - PubMed
39. 1. Diamond A. Executive Functions. Annu. Rev. Psychol. 2013;64:135–168. doi: 10.1146/annurev-psych-113011-143750. - DOI - PMC - PubMed
40. 1. Monsell S. Task switching. Trends Cogn. Sci. 2003;7:134–140. doi: 10.1016/S1364-6613(03)00028-7. - DOI - PubMed
41. 1. Lambourne K., Tomporowski P. The effect of exercise-induced arousal on cognitive task performance: A meta-regression analysis. Brain Res. 2010;1341:12–24. doi: 10.1016/j.brainres.2010.03.091. - DOI - PubMed
42. 1. Smith P.J., Blumenthal J.A., Hoffman B.M., Cooper H., Strauman T.A., Welsh-Bohmer K., Browndyke J.N., Sherwood A. Aerobic Exercise and Neurocognitive Performance: A Meta-Analytic Review of Randomized Controlled Trials. Psychosom. Med. 2010;72:239–252. doi: 10.1097/PSY.0b013e3181d14633. - DOI - PMC - PubMed
43. 1. Nybo L., Kjellstrom T., Bogataj L.K., Flouris A.D. Global heating: Attention is not enough; We need acute and appropriate actions. Temperature. 2017;4:199–201. doi: 10.1080/23328940.2017.1338930. - DOI - PMC - PubMed