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Climate and Environment

How climate and environment affect our water needs

People live, work and exercise in different environments and climatic conditions, all of which can influence daily fluid losses and water requirements. 

European dietary reference values for total water (foods plus fluids) are 2.0 litres for females (≥ 14 years) and 2.5 litres for males1. However, these Adequate Intakes (AI) apply only to moderate physical activity levels (PAL 1.6) and moderate environmental temperatures1. While the requirement for water is probably lower than the AI for some individuals, or in colder environments where sweat losses are low or absent, in most cases requirements will exceed the AI due to water losses from sweat and respiration. Here we will discuss the various circumstances where water needs may be higher than the AI.


Sweat production is affected by2:

Impact of workplaces

Cold temperatures


Practical points for climbers, or those working at altitude, e.g. aircrew, are:

The EHI thanks to Dr. Hans Braun, EHI Science Advisory Board member, German Sport University Cologne and German Research Centre of Elite Sport (Germany), for providing the content used as a basis for the text in this section. His full scientific article entitled Effects of climate and Environment on water needs can be found in our section Selected Articles.

1- EFSA Panel on Dietetic Products, Nutrition, and Allergies (NDA). EFSA Journal 2010; 8(3):1459. Available at: www.efsa.europa.eu/en/efsajournal/pub/1459.htm
2- Sawka MN, Burke LM, Eichner ER, Maughan RJ, Montain SJ, Stachenfeld NS. American College of Sports Medicine position stand. Exercise and fluid replacement. Medicine & Science in Sports & Exercise. 2007; 39: 377–390.
3- Bates PG, Miller VS. Sweat Rate and sodium loss during work in the heat. Journal of Occupational Medicine and Toxicology 2008, 3:4
4- Brake DJ, Bates GP. Fluid losses and hydration status of industrial workers under thermal stress working extended shifts. Occupational and Environmental Medicine 2003;60:90–96
5- Bates PG, Miller VS and Joubert DM. Hydration Status of Expatriate Manual Workers During Summer in the Middle East. Annals of Occupational Hygiene. 2010, 54, 137-143
6- Freund BJ, Young AJ. Environmental influences on body fluid balance during exercise: cold stress. In: Body Fluid Balance in Exercise and Sport, E. R. Buskirk and S. M. Puhl. Boca Raton: CRC Press, 1996, pp 159–196
7- Armstrong LE. Performing in Extreme Environments. Champaign: Human Kinetics, 2000, pp 189-190
8- Hailes WS, Cuddy JS, Slivka DS, Hansen K, Ruby BC. Water Turnover and Core Temperature on Mount Rainier. Wilderness & Environmental Medicine. 2012; 23, 255-259.
9- Reilly T, Waterhouse J. Sport, Exercise and Environmental Physiology. London: Elsevier, 2005, pp 96-97