newsletter #1
Inside Our First Newsletter: Research, Conferences & HRV Insights
Welcome
Hello and welcome to this month's HRV LABorde Newsletter!
Cold-water exposure has become one of the most talked-about recovery strategies in sport. From cold showers and ice baths to the mammalian dive reflex, athletes and coaches are increasingly using cold as part of their routines. But do these methods work in the same way, and what can they actually tell us about our nervous system?
Following a recent feature in The New York Times, Prof. Dr. Dr. Sylvain Laborde shares the science behind different forms of cold exposure—and why heart rate variability (HRV) offers valuable insight into how the body responds.
Main Insight
Cold-water exposure is often discussed as if it were one single intervention. In reality, different forms of cold exposure trigger different physiological responses.
A cold shower causes an immediate activation of the sympathetic nervous system—the body's "fight-or-flight" response. Heart rate and adrenaline increase rapidly, making many people feel more awake and alert. This effect, however, is short-lived and should not automatically be interpreted as improved performance.
Full-body cold-water immersion, such as an ice bath, adds another important stimulus: hydrostatic pressure. The pressure exerted by the surrounding water influences cardiovascular function while the body responds to the cold. Once the initial cold shock subsides, many people experience a shift toward a calmer physiological state.
A third method is cold facial immersion, often referred to as activating the mammalian dive reflex. Cooling the face—particularly around the forehead, eyes and nose—can trigger a slowing of the heart rate while maintaining alertness. Prof. Laborde describes this combination as being "vigilant but calm"—a physiological state that may be particularly valuable in situations requiring both focus and self-control.
Importantly, no single cold intervention should be viewed as universally "best." The physiological response depends on the type of exposure, its duration, the individual, and the intended purpose—whether recovery, regulation, or preparation for performance.
HRV Perspective
Heart rate variability provides a valuable window into how the autonomic nervous system regulates the heart.
Cold exposure illustrates why HRV should always be interpreted in context. The autonomic response changes over time: the first moments of cold exposure differ substantially from the period that follows. Consequently, an HRV measurement taken immediately after entering cold water may reflect a different physiological state than one measured after recovery.
HRV should therefore never be interpreted in isolation. Measurement timing, breathing, recent physical activity, sleep, psychological stress and the type of cold exposure all influence the body's response.
HRV is most informative when it helps us understand patterns of autonomic regulation over time—not when it is reduced to a single number.
From Science to Practice - Three practical takeaways
🧊 Not all cold exposure is the same.
Cold showers, ice baths and facial immersion each produce distinct physiological responses.
⏱️ Context and timing matter.
When HRV is measured can strongly influence how the results should be interpreted.
🧠 Use HRV as one piece of the puzzle.
Combine HRV with information about training load, recovery, sleep and subjective well-being to gain a more complete picture of physiological regulation.
HRV Challenge - Test your HRV knowledge!
1. Which branch of the autonomic nervous system is primarily activated immediately after a cold shower?
A) Parasympathetic nervous system
B) Sympathetic nervous system
C) Enteric nervous system
2. Which form of cold exposure is associated with activation of the mammalian dive reflex?
A) Full-body ice bath
B) Cold shower
C) Facial immersion in cold water
3. Which statement about HRV interpretation is most accurate?
A) A single HRV value is enough to determine recovery status.
B) HRV should always be interpreted together with context and measurement conditions.
C) HRV always increases after cold exposure.
💡 The answers will be revealed in next month's newsletter.
From the LAB
This month, the HRV LABorde participated in the 17th FEPSAC European Congress of Sport and Exercise Psychology in Timișoara, Romania—a fantastic opportunity to exchange ideas with researchers and practitioners from across the world.
Before the conference officially began, Prof. Dr. Dr. Sylvain Laborde led a pre-conference workshop and even explored the city with a half-marathon along the Bega River, collecting fresh HRV data to discuss during the sessions.
Throughout the congress, we delivered three interactive workshops covering:
- HRV: Science and Practical Applications in Sport Psychology
- HRV: From Theory to Practice
- Breathing Techniques for Performance, Health, and Well-Being (with Maša Iskra)
Each workshop concluded with an HRV Kahoot quiz, where participants competed to win signed copies of our books.
The conference also provided an excellent opportunity to discuss our recent book, Heart Rate Variability: Science and Strategies for Peak Performance, co-authored by Sylvain Laborde, Emma Mosley, Marco Altini, and Daniel Plews.
Beyond the presentations, the most valuable part of FEPSAC was the opportunity to connect with colleagues, exchange ideas, and build new collaborations. These conversations continue to inspire future research and the ongoing work of the HRV LABorde.
📰 Featured Article - The New York Times
Cold Water Exposure, Performance and the Science Behind the Trend
Read the full article here → https://www.nytimes.com/athletic/7298113/2026/05/26/rafael-nadal-french-open-tennis-cold-shower/?redirected=1
Thank you for being part of the HRV LABorde community.
We look forward to sharing more evidence-based insights on heart rate variability, breathing science and performance psychophysiology in next month's edition.