Outcome
Performance in heat
Heat punishes ego pacing; you need acclimation and cooling strategy to execute.
What to do first
- • Practice pacing downshifts by temperature and humidity.
- • Consider heat acclimation blocks 10–21 days pre-race.
- • Use simple cooling tactics: cold fluids, ice, shade, and smart start pacing.
Related topic guides
Protocols and decisions connected to this outcome.
Heat acclimation: a protocol you can actually execute
Evidence-informed protocol: Heat acclimation: a protocol you can actually execute. Practical steps, who it helps, and what to watch out for.
Long-course triathlon research: pacing, fueling and readiness
Evidence-informed protocol: Long-course triathlon research: pacing, fueling and readiness. Practical steps, who it helps, and what to watch out for.
Study library (reference)
Studies that measured this outcome.
Short-term heat acclimation training improves physical performance: a systematic review, and exploration of physiological adaptations and application for team sports.
PMID 24817609 (2014): heat acclimation — Performance in heat, Time-trial performance (study note for endurance athletes).
Efficacy of Heat Mitigation Strategies on Core Temperature and Endurance Exercise: A Meta-Analysis.
PMID 30842739 (2019): heat acclimation — Performance in heat (study note for endurance athletes).
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).
The effect of post-exercise heat exposure (passive heat acclimation) on endurance exercise performance: a systematic review and meta-analysis.
PMID 39762944 (2025): heat acclimation, sauna — Performance in heat, Time-trial performance (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).
Multiple-Transportable Carbohydrate Effect on Long-Distance Triathlon Performance.
PMID 28350714 (2017): carbohydrate, carb — Time to exhaustion, Time-trial performance, Fat oxidation, Performance in heat, Recovery speed (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).
Pre-cooling alters pacing profiles resulting in no additional benefit to 20-km self-paced maximal cycling time-trial performance in heat acclimated endurance athletes.
PMID 40393849 (2025): pacing — Time-trial performance, Performance in heat (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).
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Performance Science Lab
Research summaries for endurance athletes, with study context, practical protocols, and clear limitations.
Long-course triathlon research: pacing, fueling and readiness
Evidence-informed protocol: Long-course triathlon research: pacing, fueling and readiness. Practical steps, who it helps, and what to watch out for.
Hydration Status After an Ironman Triathlon: A Meta-A… (PMID 31915479)
PMID 31915479 (2019): evidence summary and practical limits for endurance athletes.
Sources
- Short-term heat acclimation training improves physical performance: a systematic review, and exploration of physiological adaptations and application for team sports.
- Efficacy of Heat Mitigation Strategies on Core Temperature and Endurance Exercise: A Meta-Analysis.
- Hydration Status After an Ironman Triathlon: A Meta-Analysis.
- The effect of post-exercise heat exposure (passive heat acclimation) on endurance exercise performance: a systematic review and 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.
- Multiple-Transportable Carbohydrate Effect on Long-Distance Triathlon Performance.
- Effects of oral sodium supplementation on indices of thermoregulation in trained, endurance athletes.