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Dehydration: what happens in your body and how you can avoid the harmful effects.

by Nix Biosensors

Athletes biking

Dehydration: what happens in your body and how you can avoid the harmful effects.

Fact: When you go out for a run or for a ride, your body’s heat production can increase up to twenty-fold compared to rest.

What happens in your body:

  • Loss of body water through sweat manifests primarily in a lowered blood volume, or hypovolemia.
  • When blood volume is low, it compromises the body's ability to deliver oxygen as efficiently.
  • To compensate, heart rate and respiratory rate increase.
  • If dehydration, and therefore blood volume, continues to worsen, circulation can be reduced to the extremities, in order to preserve critical oxygen levels for the vital organs. 

How it affects you:

  • 87% of endurance athletes are physically impaired during their workouts and competitions due to dehydration.
  • In addition to physical impairments, mild dehydration causes cognitive impairments up to 20% affecting speed, accuracy, and memory.
  • Mild dehydration can result in an endurance performance impairment of up to 29%.
  • When an athlete consumes only water and neglects to replenish electrolytes, hyponatremia can occur, which causes the body’s cells to swell and can be life-threatening. 

To avoid dehydration: 

  • Hydrate early. By the time you feel thirsty it's already too late.
  • Put in as much effort to properly hydrate during short distances as you do for longer distances.
  • Ensure that you're consuming both water and electrolytes as your body needs both in order to avoid dehydration. 

*Nix provides real-time hydration data that tells athletes when, what, and how much to drink during a workout. Athletes can view their individual sweat data on a phone, watch, or bike computer. For more information visit

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