Performance Science Lab
Hydration lab
Hydration is context dependent: heat, sweat rate, and sodium losses change the plan.
Start here
- • Avoid extremes: both dehydration and overhydration can ruin performance.
- • Use simple field rules: thirst + body mass trend + urine color, not panic.
- • Treat electrolytes as a tool for heavy sweaters, not a default for everyone.
Study library (reference)
Individual studies for deeper reading.
Hydration Status After an Ironman Triathlon: A Meta-Analysis.
PMID 31915479 (2019): hydration, dehydration — Time to exhaustion, Performance in heat, Cramp risk, Time-trial performance, Recovery speed (study note for endurance athletes).
Sodium Hyperhydration Improves Performance With No Change in Thermal and Cardiovascular Strain in Female Cyclists Exercising in the Heat Across the Menstrual Cycle.
PMID 39591960 (2025): hydration, fluid — Time to exhaustion, Performance in heat, Cramp risk (study note for endurance athletes).
Alkaline water improves exercise-induced metabolic acidosis and enhances anaerobic exercise performance in combat sport athletes.
PMID 30452459 (2018): hydration, sodium — Time to exhaustion, Performance in heat, Cramp risk (study note for endurance athletes).
Effects of oral sodium supplementation on indices of thermoregulation in trained, endurance athletes.
PMID 25729305 (2015): hydration, fluid — Time to exhaustion, Performance in heat, Cramp risk (study note for endurance athletes).
Sodium supplementation has no effect on endurance performance during a cycling time-trial in cool conditions: a randomised cross-over trial.
PMID 23731903 (2013): hydration, sodium — Time to exhaustion, Performance in heat, Cramp risk (study note for endurance athletes).
The Addition of Glycerol and Sodium Chloride to a Hyperhydration Protocol Does Not Improve Half-Marathon Time-Trial Performance in Trained Runners in Warm Conditions.
PMID 40139199 (2025): hydration, fluid — Time to exhaustion, Performance in heat, Cramp risk (study note for endurance athletes).
Exploring the Influence of Acid-Base Status on Athletic Performance during Simulated Three-Day 400 m Race.
PMID 38999735 (2024): hydration — Time to exhaustion, Performance in heat, Cramp risk (study note for endurance athletes).
Effects of skim milk and isotonic drink consumption before exercise on fluid homeostasis and time-trial performance in cyclists: a randomized cross-over study.
PMID 32228635 (2020): hydration, fluid — Time to exhaustion, Performance in heat, Cramp risk (study note for endurance athletes).
Effects of oral salt supplementation on physical performance during a half-ironman: A randomized controlled trial.
PMID 25683094 (2016): electrolyte — Time to exhaustion, Performance in heat, Cramp risk, Time-trial performance, Recovery speed (study note for endurance athletes).
Hydration Status and Sodium Balance of Endurance Runners Consuming Postexercise Supplements of Varying Nutrient Content.
PMID 25811075 (2015): hydration, sodium — Time to exhaustion, Performance in heat, Cramp risk (study note for endurance athletes).
Pre-exercise hyperhydration-induced bodyweight gain does not alter prolonged treadmill running time-trial performance in warm ambient conditions.
PMID 23016126 (2012): hydration, sodium — Time to exhaustion, Performance in heat, Cramp risk (study note for endurance athletes).
Consumption of a Branched-Chain Amino Acids-Containing Sports Beverage During 21 km of Running Reduces Dehydration, Lowers Muscle Damage, and Prevents a Decline in Lower Limb Strength.
PMID 39599586 (2024): hydration, dehydration — Time to exhaustion, Performance in heat, Cramp risk (study note for endurance athletes).
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Sources
- Hydration Status After an Ironman Triathlon: A Meta-Analysis.
- Sodium Hyperhydration Improves Performance With No Change in Thermal and Cardiovascular Strain in Female Cyclists Exercising in the Heat Across the Menstrual Cycle.
- Alkaline water improves exercise-induced metabolic acidosis and enhances anaerobic exercise performance in combat sport athletes.
- Effects of oral sodium supplementation on indices of thermoregulation in trained, endurance athletes.
- Sodium supplementation has no effect on endurance performance during a cycling time-trial in cool conditions: a randomised cross-over trial.
- The Addition of Glycerol and Sodium Chloride to a Hyperhydration Protocol Does Not Improve Half-Marathon Time-Trial Performance in Trained Runners in Warm Conditions.
- Exploring the Influence of Acid-Base Status on Athletic Performance during Simulated Three-Day 400 m Race.
- Effects of skim milk and isotonic drink consumption before exercise on fluid homeostasis and time-trial performance in cyclists: a randomized cross-over study.