Pre-Race and In-Race Cooling Strategy
Heat-race essentials: evidence-based pre-cooling and per-cooling doses
Race-Day Conditions
Marathon (42.2K)
Early 6:00
Typical Taiwan marathon starts in Kaohsiung, Wan Jin Shi, or Tianzhong: 6 AM around 22-26°C / 75-90% humidity
Core Temperature Limit and Performance Drop
Core temperature around 39.5-40°C is a critical point where endurance performance can decline rapidly (González-Alonso 1999, "Critical Temperature" hypothesis).
Pre-cooling increases your thermal reserve; studies show ice slurry can extend performance by about 5-15%.
Heat Stress Assessment
Estimated WBGT
26.0°C
Heat risk
High
Recommended cooling
Pre-cool + per-cooling
Estimated pace loss
−5%
WBGT 23-28°C: Ely 2007 suggests half-marathon times can average +2-5%; use full pre-cooling and in-race cooling.
Pre-Cooling — 30-60 Minutes Before Start
| Method | Dose | Core temp drop | Evidence |
|---|---|---|---|
| Ice slurry Crushed ice + sports drink, taken in portions | 7.5 g/kg body mass, 30-45 min before | −0.5-0.7°C | Siegel 2010 MSSE |
| Cold water immersion Cold bath / torso immersion | 12-15°C water for 15-30 min | −0.4-0.6°C | Marino 2002 |
| Cold drinks 4°C sports drink in portions | 7-12 mL/kg, 15-30 min before | −0.2-0.3°C | Burdon 2010 |
| Cooling vest Ice-pack vest during warm-up | 20-30 min | −0.3-0.4°C | Bogerd 2010 |
| Mixed strategy Ice slurry + vest + cold water | 30-min combination | −0.7-1.0°C | Bongers 2015 review |
Per-Cooling — During the Race
- Ice water / cold water: at each 5 km aid station, drink and pour over head, neck, and upper back. Tyler 2015 found external cooling can lower rectal temperature by 0.3-0.5°C.
- Sponge / ice towel: target neck and wrists where blood vessels are dense; more useful than cooling limbs.
- Drink temperature: 5-10°C drinks remove an extra 0.05-0.1°C of core heat versus room temperature drinks (Burdon 2010).
- Ice slurry: harder to execute but strongest effect; melting ice absorbs far more heat through latent heat.
- Menthol mouth rinse: rinse 25 mL of 0.01% menthol for 5-10 seconds without swallowing. Stevens 2017 showed lower perceived heat stress.
Your Race-Day Cooling Timeline
T-90 min：Arrive, stay out of sun, drink 500 mL cool fluid
T-60 min：Start ice slurry, split about 500 mL into 3 servings
T-45 min：Put on cooling vest, do dynamic warm-up without heavy sweating
T-20 min：Warm-up jog 5-8 min at 60-70% max HR
T-5 min：Final ice-water sip, remove vest, cool neck with ice towel
5-10K：Use ice water + sponge on neck/wrists at every aid station; do not wait for thirst
10-25K：Take ice slurry if available; temperature may peak, keep pace conservative
Final 10K：If you feel unable to shed heat, slow down or stop
Research Basis
- Bongers et al. (2015, Br J Sports Med meta-analysis): pre-cooling showed an overall effect of ES=0.44 and per-cooling ES=0.40 — roughly comparable.
- Siegel et al. (2010, MSSE): ice slurry (7.5 g/kg) extended running time 19% more than cold water.
- Tyler et al. (2015, Br J Sports Med meta-analysis): cooling during exercise showed an overall effect of d=0.76 on performance and capacity.
- Stevens et al. (2016, Scand J Med Sci Sports): menthol mouth rinse lowered perceived heat stress and supported performance in heat.
- González-Alonso et al. (1999, J Appl Physiol): critical Tc around 40°C can mark the limit of endurance performance.
- Burdon et al. (2010, J Sports Sci): a 4°C drink lowered mean body temperature change by about 0.4°C more than a 37°C drink.