Tempo Run in the Heat: Acclimatisation Run Session

Session Overview

Heat acclimatisation is a proven performance booster for summer racing — and this tempo run in warm conditions builds your body’s ability to perform at threshold effort in the heat. Designed for intermediate triathletes preparing for summer races, this 45-minute session teaches thermoregulation while maintaining the physiological benefits of threshold training.

What You’ll Need

• Running shoes suitable for road or light trail
• GPS watch for pace and heart rate monitoring
• 500ml water bottle or hydration vest
• Sun protection (sunscreen, cap, sunglasses)

Warm-Up (10 minutes)

Run very easy for 8 minutes (RPE 4/10 — fully conversational), then complete 4 x 20-second strides at 5K race effort. Keep the warm-up controlled even if you feel warm — trust the process and let your body acclimatise gradually before the main effort.

Main Set

Complete 3 x 8-minute tempo efforts at threshold pace (RPE 7–8/10, approximately 10K race pace). Expect to run 10–15 seconds per kilometre slower than your normal threshold pace in cool conditions — this is normal and appropriate when heat acclimatising. Take 90 seconds easy walking or very slow jogging between each effort.

• Block 1: 8 minutes at RPE 7–8, controlled effort despite heat — 90 sec recovery
• Block 2: 8 minutes at RPE 7–8, maintaining form as warmth builds — 90 sec recovery
• Block 3: 8 minutes at RPE 7–8, focus on relaxed form and controlled breathing

Cool-Down (7 minutes)

Walk briskly for 2 minutes immediately after the last effort, then jog very easy for 5 minutes. Seek shade as soon as possible and drink cold water. Do not stretch in the direct sun — wait until you are in a cool environment.

Coaching Notes

• Do not chase normal pace targets in heat — effort (RPE) is the guide, not pace per kilometre
• Start hydrating 2 hours before the session; take small sips during recovery windows rather than gulping during efforts
• If your heart rate is 10+ beats per minute higher than normal at the same RPE, heat acclimatisation is working — this reduces over 10–14 days of consistent heat exposure
• Avoid scheduling this session in the hottest part of the day (noon–3pm) initially; build towards midday runs after 2 weeks of gradual heat exposure