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Sports Hydration: How Much Water Before, During, and After

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Before: 500 ml in the 2-3 hours prior. During: 150-250 ml every 15-20 min if over 1 h. After: 1.5 L per kg lost.

A 2% loss of body weight from dehydration already cuts aerobic performance. Knowing how much to drink and when matters, especially in sessions over 60 minutes and in hot climates.

ACSM Protocol (2007 Position Stand)

  • Before (2-3 h prior): 5-7 ml/kg = 400-560 ml for 80 kg.
  • Before (10-20 min prior): 200-300 ml extra.
  • During (over 1 h): 150-250 ml every 15-20 min.
  • After: 1.25-1.5 L per kg lost on the scale after the session.

When You Need Electrolytes

If your workout lasts more than 60-90 min, you sweat heavily, or you train in the heat, add sodium: 300-700 mg/L of drink. For small volume, a homemade isotonic drink: 1 L of water + 30 g of sugar + 1 g of salt + lemon juice.

Signs of Dehydration

  1. Dry mouth and thirst (you're already 1-2% dehydrated).
  2. Dark yellow urine.
  3. Premature fatigue, higher heart rate at the same intensity.
  4. Dizziness and nausea (3% or more).
A simple way to calibrate: weigh yourself before and after training. Each kg lost = 1 L of water to replace within the next 4 hours.

About this guide

Last reviewed
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How it is verified
We prioritize meta-analyses, systematic reviews and official positions (ISSN, ACSM, EFSA, WHO, Cochrane). Full methodology · topic: Hidratación.
Conflicts of interest
Some product links are affiliate links from Amazon España and earn us a small commission at no extra cost to you. How we fund the project.
Medical disclaimer
Educational content. Does not replace consultation with a healthcare professional. More detail.

Spotted an error in a formula or recommendation? Email us at jesus.narvaez.tames@hotmail.com. Corrections are published as an updated note on the guide.

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