It's getting hot in here...

Pascale Gränicher

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Hot weather, squishy brains – that’s a sensation we experience today at its best.

It is hard to focus if the sun constantly burns down and sweat drips tireless from and to everywhere.

Heat waves are great if there is nothing else to do than enjoying a good book under an umbrella and lying on a beach while slurping a refreshing coconut. Yeah… oven-like offices and practices are definitely not the place to be. It’s hard to focus when the brain’s engrossed in coordinating body-internal cooling processes instead of thinking intelligent stuff or composing therapy programs for injured patients.

Work-related injury rate seems to increase in hot weather. Due to physiological limitations (e.g. decreased blood flow, central fatigue), work capacity decreases above 26°C. As concentration and motor skills can be affected as well, the risk of mistakes and accidents has shown to augement during high temperatures. Additionally, body core temperature rises, what causes a shift from aerobic to anaerobic energy production. That means, muscle energy stores empty much faster and we get tired and heavy-handed.
In summer, life takes place more outside and outdoor activities seem to predispose more accidents, too (except the under-the-umbrella-book-reading-part).
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But, there are some positive facts about this hot summer – besides  a seamless tan and barbecue:

• Lots of vitamin D: Positive effect on sexual functioning in men, improving immune system and regulating inflammatory response: go outside
• Improved wound healing: Stem cell populations in sweat glands seem to support (scar) tissue regeneration and reparation: after surgery, it is okay to sweat
• Direct sunlight No. 1: Better mental health and enhanced job attitude and satisfaction: go outside!
• Direct sunlight No. 2: Beneficial effect on cardiovascular risk factors: even if you’re suffering from heat-wave-stress, your blood pressure keeps cool (up to a certain degree). A little sunbath never killed nobody!
• Sport performance: Improved peak sprinting speed. Don’t skip your trainings – muscles like warm weather (only while drinking enough water and preferably in the shadows as well as not for too long)
• Happiness: Serotonin production in our brain is directly related to the time spent in bright sunlight. Need a cheer up? Go outside!

Essential is how you cope with the hot situation – you, yourself and your patients or athletes. Important stuff like drinking enough water and using suncream needn’t to be repeated…
Remember: Your body and brain are chilling in hot weather, so try to do so, too.

References
Biedermann, T. et al. (2010). Human Eccrine Sweat Gland Cells Can Reconstitute a Stratified Epidermis. J Investig Dermatol; 130(8): 1996-2009
Holick, M.F. (2004). Sunlight and vitamin D for bone health and prevention of autoimmune diseases, cancers, and cardiovascular disease. Am J Clin Nutr; 80: 1678-1688.
Krysiak R, Szwajkosz, A. & Okopien, B. (2018). The effect of low vitamin D status on sexual functioning and depressive symptoms in apparently healthy men: a pilot study. Int J Impot Res; doi: 10.1038/s41443-018-0041-7. [Epub ahead of print]
Kjellstrom, T., Kovats, R.S., Lloyd S.J., et al. (2009). The direct impact of climat change on regional labor productivity. Arch Environ Occup Health; 64:217-227.
Lambert, G.W., Reid, C., Kaye, D.M., Jennings, G.L. & Esler, M.D. (2002). Effect of sunlight and season on serotonin turnover in the brain. Lancet; 360(9348):1840-1842.
Mihyang, A., Colarelli, S.M., O’Brien, K. & Boyaijan, M.E. (2016). Why We Need More Nature at Work: Effects of Natural Elements and Sunlight on Employee Mental Health and Work Attitudes. PLos One; 11(5): e0155614
Otte im Kampe, E., Kovats, S. & Hajat, S. (2016). Impact of high ambient temperature on unintentional injuries in high-income countries: a narrative systematic literature review. BJM Open; 11,6(2): e010399.
Sheng, R. et al. (2018). Does hot weather affect work-related injury? A case-crossover study in Guangzhou, China. Int J Hyg Environ Health; 221(3):423-428.

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