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Hydration

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Sport and Physical Activity in the Heat

Abstract

This chapter discusses the physiology of hydration, the evidence for how hydration affects performance, and practical applications for individuals who exercise. The body has an amazing ability to detect changes in body fluid, and individuals exercising are constantly losing body fluid through sweat. These losses are sensed by the body, and without proper hydration, can have a negative physiological impact. These detriments include increased heart rate and decreased cardiac output (i.e., amount of blood the heart pumps per min). The physiological consequences of mild-to-moderate dehydration include decreased performance in endurance events, along with decreased strength and power. Recent evidence suggests that mild dehydration (e.g., 1–2% body mass loss) can also lead to decrements in performance. This evidence has led to recommendations that individuals exercising should drink fluid at a rate similar to the rate of sweat loss. Calculating and using sweat rate is outlined in this chapter, which is more advantageous than just relying on thirst. Although hydration status during exercise is important, it is also important that individuals rehydrate after exercise and for the rest of the day. Last, we also examine the very important topic of overhydrating (i.e., hyponatremia).

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Authors and Affiliations

  1. Department of Health, Human Performance, and Recreation, University of Arkansas, Fayetteville, AR, USA

    Matthew S. Ganio PhD, FACSM (KSI Medical & Science Advisory Board Member) & Stavros A. Kavouras PhD, FACSM (KSI Medical & Science Advisory Board Member)

  2. Department of Kinesiology, Human Performance Laboratory, University of Connecticut, Storrs, CT, USA

    Lawrence E. Armstrong PhD, FACSM (KSI Medical & Science Advisory Board Member)

  3. Hydration Science Lab, University of Arkansas, Fayetteville, AR, USA

    Stavros A. Kavouras PhD, FACSM (KSI Medical & Science Advisory Board Member)

Authors
  1. Matthew S. Ganio PhD, FACSM
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  2. Lawrence E. Armstrong PhD, FACSM
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  3. Stavros A. Kavouras PhD, FACSM
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Corresponding author

Correspondence to Matthew S. Ganio PhD, FACSM .

Editor information

Editors and Affiliations

  1. Department of Kinesiology Director, Athletic Training Education Research Associate, Human Performance Laboratory College of Agriculture, Health, and Natural Resources, University of Connecticut, Storrs, Connecticut, USA

    Douglas J. Casa

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Ganio, M.S., Armstrong, L.E., Kavouras, S.A. (2018). Hydration. In: Casa, D. (eds) Sport and Physical Activity in the Heat. Springer, Cham. https://doi.org/10.1007/978-3-319-70217-9_5

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  • DOI: https://doi.org/10.1007/978-3-319-70217-9_5

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