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Analyzing gas exchange – VO₂, VCO₂, ventilation – is now the gold standard for understanding exercise physiology, determining ventilatory thresholds, and personalizing training. However, the market offers highly contrasting technological approaches: on the one hand, cumbersome, complex, expensive, but extremely precise systems; on the other, much more affordable and simpler devices, but with limited accuracy. This article discusses data quality, trade-offs, and why PAIRFS dec

ZoneX analyzes respiration and it is important that it is used correctly to provide reliable and high-quality information. The following video explains how to do this: Steps to attach ZoneX to the mask Here are the logical steps to mount ZoneX onto the respirator mask, as illustrated in the video: Insert the internal breathing tube into the mask — this tube acts as a conduit between your mouth (or airway) and the ZoneX sensor. It ensures that inhaled/exhaled air passes into

What better way to discover what's inside the box of the first device capable of measuring your ventilatory thresholds (VT1 / VT2) directly in the field than with a complete unboxing ? 📦 What's in the ZoneX box? In the video, you will discover: ✔️ The ZoneX device Compact and lightweight (210g), it's designed to capture your respiratory flow with high precision while remaining comfortable. Its architecture was conceived for real-world use, outside of a laboratory setting.

Training zones, ventilatory thresholds, and physiological responses are not universal. They vary considerably depending on athletic experience, age, sex, sport, and even lifestyle . Understanding these differences is essential for personalizing a training plan and achieving measurable progress—while avoiding common mistakes associated with overly generic zones. Here is a clear overview, based on the available scientific data. 1. Beginner vs. Trained Athlete 🔶 Beginner VT1 a

Training zones are an essential tool for structuring endurance training. However, their use often remains imprecise: poorly calibrated zones, misinterpreted intensities, misunderstood indicators… The result: ineffective sessions, limited progress, and even a risk of overtraining. Here are the most frequent mistakes , and above all how to avoid them with an approach focused on breathing and ventilatory thresholds. Mistake 1 — Thinking that heart rate provides precise zones H

When discussing training zones, many refer to fixed percentages of VO₂ max, heart rate, or power. However, ventilatory thresholds — VT1 & VT2 — are not immutable . They evolve with training, fitness level, physiological adaptations, and… inter-individual differences. Understanding their variability is essential to remaining effective, relevant, and accurate in programming. Why do VT1/VT2 change with training? Improved aerobic endurance : As the body adapts to training—parti

Connected devices have transformed training: heart rate, power, cadence, speed, oxygen saturation… but one essential parameter is still largely absent from current wearables: breathing . However, breathing is the most direct, sensitive and reliable physiological signal for understanding what is happening in an athlete's body. After years of innovations focused on cardio and power, a new generation of sensors is emerging: respiratory wearables . And this revolution begins no

Zone 2 has become an essential term in endurance training. Cyclists, runners, triathletes, coaches, and scientists alike are all talking about this "moderate endurance" work, which forms the basis of sustainable performance. But what exactly is Zone 2? How can you be sure you're training there correctly? What physiological benefits can you really expect from it? And for which activities is it most useful? We take stock, with an approach centered on physiology — and on ventil

Ventilatory thresholds VT1 and VT2 are essential physiological benchmarks for structuring intelligent training. Unlike traditional methods based solely on heart rate, power, or percentages of FTP, ventilatory thresholds directly detect the body's internal response to exertion. Building a plan based on VT1/VT2 transforms training into a more precise, reproducible, and individualized process. This article shows you how to use your ventilatory thresholds to structure your zone

And how does this fit into the long-term vision of a portable CPET? In endurance sports, breathing is one of the most powerful physiological signals. Yet, measuring respiratory gases remains a complex field, dominated by cumbersome, expensive systems reserved for laboratories. At PAIRFS, we want to change that: to make key metabolic information accessible to all athletes , on the field, during training. But to achieve this, one fundamental rule must be respected: 👉 Don't me

Ventilatory thresholds (VT1 and VT2) have become central indicators for measuring aerobic performance, structuring training zones, calibrating intensity and tracking the progress of athletes. Unlike traditional methods based on heart rate or power, ventilatory thresholds directly describe the body's internal physiological response to exertion. This comprehensive guide explains: What are VT1 and VT2? how they measure themselves, their link with the energy sectors, their role

Zone 2 has become a staple of endurance training. It's presented as the zone of fundamental endurance, mitochondrial development, and "easy but useful" work. But in reality, zone 2 only makes sense if your VT1 is correctly identified . If your VT1 is misplaced — too high or too low — then your entire zone 2 becomes incorrect : inadequate intensity, diminished adaptations, unnecessary fatigue… and stagnant progress. Here's why. 1. Zone 2 comes from VT1, not from some magic p

Why compare short vs long tests? To identify your ventilatory thresholds (VT1 / VT2) and define your true physiological zones , you can perform different types of tests. But should we prioritize: a short test (rapid incremental test), a long test (slow progress), or a hybrid protocol? Each format has its advantages… and its limitations. 👉 This guide helps you understand which test is best suited to YOUR sporting activity. 1. The purpose of the test: to identify VT1 and V

The climbs are the ultimate test of all cyclosportive events. It's where gaps are created—or where you blow up. Yet, it's not just power or leg strength that dictates your ability to maintain a pace: it's your breathing . Understanding and using your ventilatory thresholds (VT1 & VT2) in climbs radically changes the way you approach hills, restart, and — above all — recover between two difficulties. In this article, discover how breathing becomes your best pacing tool , wi

Ventilatory threshold 2 (VT2) is a key marker for athletes: it's the point at which ventilation spikes, acidosis sets in, and exertion suddenly becomes very taxing. Improving VT2 means: increase your ability to sustain high intensity, better tolerate lactate, to be more powerful on restarts, bumps or accelerations, delay the explosion in competition. For this, intervals are not the only option. 👉 Respiratory muscle training plays a major role — and it is often neglected. In

Endurance sports already make extensive use of ventilatory thresholds (VT1 and VT2) to structure training. But what is less well known is that these thresholds are just as crucial in team sports , where the effort is much more intermittent, explosive and unpredictable. Football, rugby, basketball, handball, hockey: ➡️ All these sports rely on alternating periods of intense effort, short recovery periods, and rapid restarts. And in these contexts, respiratory capacity plays a

Triathlon is one of the sports where intensity management is the most complex. Three disciplines, three body positions, three different respiratory constraints… and yet a single respiratory system to manage everything. Understanding your ventilatory thresholds (VT1 & VT2) is the most reliable way to control effort from start to finish, avoid burning out during running, and optimize your race management. 1. Why breathing is essential in triathlon Unlike heart rate (which reac

In endurance sports, we often talk about basic endurance, Zone 2 or threshold training. But when it comes to accelerations, restarts, short sprints or decisive passages , a threshold becomes central: VT2 . Whether you are a cyclist, runner, trail runner or triathlete, your ability to produce intense effort without "exploding" depends directly on how your ventilation reacts around VT2. 1. Why explosive efforts depend on your ventilation A sprint or acceleration isn't just ab

In trail running, pace is not a reliable indicator: the same effort can vary from one to three times as much depending on the slope, the ground, the altitude or the technicality. But there is an internal indicator which remains accurate everywhere: breathing . The way you ventilate reveals in real time: your energy sector, your level of fatigue, your positioning relative to VT1 and VT2, your ability to sustain the effort. That's why breathing is the most reliable tool for m

Altitude profoundly alters the way the body produces energy. Less oxygen, more ventilation, faster fatigue: it is an environment where breathing becomes a central indicator to understand your physiology. And this change is directly reflected in your ventilatory thresholds (VT1 & VT2) , which do not behave at all like they do at sea level. 1. Why altitude changes your breathing From 1,500–2,000 m altitude, oxygen pressure decreases. As a result, your body has to breathe more