How dehydration affects performance

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dehydration affects performanceFluid loss, or dehydration due to activity happens daily in all of us and without replacing that loss – your entire body can be affected. The idea that dehydration can affect you physical and cognitive performance has been around for an age, but since then there has been a lot of research done to figure out how.

Since a study by et al in 1955 showed a decrease in VO2max with dehydration, a number of studies have been done to follow up on this and various other ways dehydration affects performance.

Dehydration can and often is induced by exercise, but there are a lot of other variables which come into play including:

  • Type of exercise or physical activity
  • Temperature and humidity
  • Nutrition and hydration levels before activity

Given all the various studies that looked all the things that dehydration can impair, a recent study(1) has critically analysed the current literature and this is what they found:

  1. Dehydration caused a decrease in aerobic performance which can be generalised to all physical activity that lasts for more than 15 seconds
  2. Exercising with restricted hydration caused decreased performance, increased heart rate and increased core body temperature
  3. There were no changes in performance for exercise that lasted less than 15 seconds such as the vertical jump test. (this is because a different energy system is used for intense exercise less than 15 seconds that does not need water – the alactic component)

How to check if dehydratedThat, in a nutshell, is the current research on how hydration affects performance and the main thing to take from it is that, yes, it does affect performance (unless you are a 100m sprinter maybe) and you should do your best to be hydrated before exercise and during, while of course being careful not to over-hydrate as this can cause it’s own problems.


Check out this earlier post on how to keep an eye on your hydration and what you should aim for.