A focused guide to using heat training during winter—why it works, what adaptations you’re actually chasing, and how to implement sauna, hot water immersion, or layering protocols safely and strategically.

Heat training is usually framed as something you do before a hot race. But the physiological adaptations don’t care what month it is. Plasma volume expansion, improved thermal regulation, and cardiovascular efficiency can all support training during winter—even if race day will be cold.

This episode is an edited and streamlined version of Episode 4, where we originally covered heat training in depth. Here, we’ve removed the broader discussion of racing in hot environments and narrowed the focus to one question: How can runners use heat protocols intentionally during winter training to enhance performance?

Episode Description

This episode is a practical, research-backed breakdown of how to apply heat training protocols during winter running.

Matt and Molly revisit the primary studies that shaped their understanding of heat adaptation, then walk through:

• Why heat training matters beyond hot race preparation

• The physiological mechanisms behind heat adaptations

• The three core methods for inducing heat stress

• How to implement layering, sauna, and hot water immersion during winter

• How long adaptations last and how to maintain them

• When to schedule heat exposure within a training cycle

• Key safety considerations to avoid digging a recovery hole

Rather than treating heat training as seasonal, this episode reframes it as a tool. One that, when applied carefully, can support cardiovascular development, resilience, and recovery during winter blocks when training quality matters most.

Chapters

00:00 Introduction to Heat Training and Personal Experiences Driving Our Understanding

01:11 Context for Episode And Focus On Heat Training Protocols During Winter Training

02:23 The Primary Studies We Reviewed In Preparation For This Episode

03:57 Major Reasons Why You Should Care About Heat Training

06:39 Why Running In The Heat Is Challenging

11:41 Anecdotal Experience with Heat Training In Recent Ultra Performances

13:30 The Three Heat Training Methods We Cover and General Physiological Benefits of Heat Training

14:37 Thermal Regulation and Adaptations

16:46 Protocol by Protocol Analysis

17:09 Protocol 2: Adding Layers to Augment Heat of The Natural Environment

36:28 Protocol 3: Hot Dry Sauna and Hot Water Immersion (HWI) - Actual Implementation Steps

38:39 Protocol 3: Hot Sauna Benefits and Considerations

41:01 Protocol 3: How Water Immersion (HWI) Benefits and Considerations

46:03 Maintaining Heat Training Adaptations

48:26 Timing and Strategy for Heat Training

52:31 Safety Considerations When Heat Training

Top 5 Takeaways

1. Heat training is not just for hot races.
   The adaptations—plasma volume expansion, improved cardiovascular efficiency, and thermoregulation—can support winter training blocks as well.

2. Layering and passive heat exposure are often the most practical winter tools.
   You don’t need a hot climate. Strategic layering during runs or post-workout sauna/HWI can induce meaningful adaptations.

3. The goal is controlled stress, not exhaustion.
   You’re chasing adaptation, not dehydration or glycogen depletion. Overdoing it can compromise recovery.

4. Adaptations are transient but quickly re-established.
   Benefits can fade within roughly two weeks without exposure, but can often be restored in just a few sessions.

5. Safety matters more in winter than people think.
   Heat protocols layered onto hard winter training can create cumulative stress. Hydration, fueling, iron status, and recovery awareness are essential.