In this episode, we explain the difference between heat acclimatisation and heat acclimation. Acclimatisation usually refers to adapting naturally to a hot environment, while acclimation is a more controlled process using tools like hot-water immersion, sauna, or structured heat exposure.

The key message is that heat adaptation is not just about “getting used to suffering.” It creates real physiological changes: lower heart rate at a given pace, earlier and more efficient sweating, better temperature regulation, reduced perceived effort, and improved tolerance when racing or training in warm conditions.

For ultrarunners, this matters because heat can compromise pacing, hydration, fuelling, digestion, decision-making, and overall race performance. However, heat work should be treated as training stress, not recovery.

The episode gives practical starting points for both hot-water immersion and sauna: begin with short exposures of 10–15 minutes after easy runs, then gradually build towards 20–30 minutes, and only progress further if well tolerated. It also highlights precautions: avoid heat exposure when ill, dehydrated, dizzy, very fatigued, or medically vulnerable.

The main takeaway: do not wait until race day to discover how your body responds to heat. Train the heat response before the weather tests you.

Key references:

1. Racinais et al. 2015 — Consensus Recommendations on Training and Competing in the Heat

2. Racinais et al. 2023 — IOC Consensus Statement on Recommendations and Regulations for Sport Events in the Heat

3. Zurawlew et al. 2018 — Post-exercise Hot Water Immersion as a Practical Heat Acclimation Strategy

4. Zurawlew et al. 2019 — Hot Water Immersion, Retention of Heat Adaptations

5. Scoon et al. 2007 — Post-exercise Sauna Bathing and Endurance Performance in Competitive Runners

6. Casa et al. 2015 — National Athletic Trainers’ Association Position Statement: Exertional Heat Illnesses

7. Roberts et al. 2021/2023 — ACSM Expert Consensus Statement on Exertional Heat Illness