L'exposition directe de la tête au rayonnement thermique solaire altère les performances motrices et cognitives

Aperçu: G.M.

Les problèmes de santé et de performance provoqués par le stress thermique sont des défis sociétaux qui s'étendent géographiquement et s'intensifient avec le réchauffement climatique. Pourtant, la science sous-estime peut-être le véritable impact, car aucune étude n'a évalué les effets de l'exposition au soleil sur la température et le  fonctionnement du cerveau humain. 

En conséquence, les performances dans les tâches cognitives dominées et combinées motrices-cognitives et les marqueurs de l'augmentation de la température du tronc cérébral ont été évalués lors d'une exposition à la lumière solaire simulée (égale à ~ 1000 watts/m2). 

L'exposition aiguë n'a affecté aucune mesure de performance, tandis qu'une exposition prolongée de la tête et du cou a provoqué une élévation de la température centrale de 1 °C et des altérations significatives des performances cognitives et motrices. Il est important de noter que les déficiences sont apparues à des niveaux d'hyperthermie considérablement inférieurs par rapport aux expériences précédentes et aux essais de la présente étude sans chauffage radiant de la tête. 

Ces résultats soulignent l'importance d'inclure l'effet du rayonnement solaire sur la tête et le cou dans les futures évaluations scientifiques des impacts du stress thermique environnemental et de la protection spécifique de la tête afin de minimiser les effets néfastes.

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. 2020 May 8;10(1):7812.  doi: 10.1038/s41598-020-64768-w.

Direct exposure of the head to solar heat radiation impairs motor-cognitive performance

Jacob F Piil  ¹ , Lasse Christiansen  ^{2   3} , Nathan B Morris  ² , C Jacob Mikkelsen  ² , Leonidas G Ioannou  ^{2   4} , Andreas D Flouris  ⁴ , Jesper Lundbye-Jensen  ² , Lars Nybo  ²

Affiliations

• PMID: 32385322
• PMCID: PMC7210303
• DOI: 10.1038/s41598-020-64768-w

Free PMC article

Abstract

Health and performance impairments provoked by thermal stress are societal challenges geographically spreading and intensifying with global warming. Yet, science may be underestimating the true impact, since no study has evaluated effects of sunlight exposure on human brain temperature and function. Accordingly, performance in cognitively dominated and combined motor-cognitive tasks and markers of rising brainstem temperature were evaluated during exposure to simulated sunlight (equal to ~1000 watt/m²). Acute exposure did not affect any performance measures, whereas prolonged exposure of the head and neck provoked an elevation of the core temperature by 1 °C and significant impairments of cognitively dominated and motor task performances. Importantly, impairments emerged at considerably lower hyperthermia levels compared to previous experiments and to the trials in the presents study without radiant heating of the head. These findings highlight the importance of including the effect of sunlight radiative heating of the head and neck in future scientific evaluations of environmental heat stress impacts and specific protection of the head to minimize detrimental effects.

Conflict of interest statement

The authors declare no competing interests.

Figures

Figure 1

Complex motor task performance. Tracking…

Figure 2

Changes in interval between peak…

Figure 3

Visual representation of brain stem…

Figure 4

Schematic drawing of radiation setup.…

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