Zone 2 is the top of your aerobic base: the hardest steady effort you can hold while your body is still fueled mainly by fat. It is the most valuable training intensity for almost every endurance and mountain athlete, and it is the one most people get wrong. The reason is simple. Most Zone 2 training advice starts from a formula (220 minus your age) instead of being based on your physiology. This guide explains what Zone 2 really is, why the standard formula misleads you, and how to find your true Zone 2 with a field test you can…
Author: Uphill Athlete
Practical strategies to optimize gas exchange through breathing techniques, hydration and iron management, proper acclimatization protocols, and self-awareness of their body’s individual responses to hypoxic stress.
Practical coaching insights from Martin Zhor and Ben Morley, including field observations from UTMB and high-altitude expeditions.
Assessing your Zone 2, or more accurately, your Aerobic Threshold is important because that is how you will correctly define your training intensities for different workouts. This article summarizes the current best-practice recommendations for aerobic self-assessment. Embedded throughout you will find links to older articles—for those who want more information about a specific method. In our books Training for the New Alpinism and Training for the Uphill Athlete, as well on this site, we have devoted copious amounts of ink to helping athletes assess their fitness. In our efforts to cover all the angles, we’ve created a sprawling menu of…
Why Metabolic Efficiency Matters Consider this week of mountain activity, all performed by one person: Days 1–2: Approach on foot from Chamonix to the north face of the Grand Jorasses. Climb the Colton-MacIntyre route (ED, VI, 1,200 meters) and descend into Italy. Total time: 27 hours. Total fuel consumed: two gels and half a liter of water. Day 3: Pace a friend in a 50K trail race. Day 4: Win the Chamonix Vertical K race. Days 5–6: Travel to Alaska. Day 7: Win the Mountain Marathon in Seward, Alaska, setting a new course record. Kilian Jornet did all of this…
Many female endurance athletes underestimate strength training. In mountain sports, it may be the most important training you do.
Discover a practical goal-setting framework for endurance athletes that prioritizes process, consistency, and long-term performance.
Discover practical foot and ankle care strategies tailored for endurance athletes—from biomechanics and injury prevention to recovery tactics and footwear insights—to support your training, performance and long-term mobility.
If you are like us, you want to be ready when the snow comes and you can get into the back country. Even if you’ve fallen off the endurance training wagon with all the rock climbing you’ve been doing, you’ve still got time to make some appreciable gains in the next 8 weeks. A couple of years ago we published an article called Preseason Ski Touring Training (you are encouraged to read it for background info) which outlined the training in general terms and even described some typical workouts. But it was not a detailed day by day plan like…
Why You Need to Know Your Aerobic Threshold? Pinpointing your Aerobic Threshold (AeT) heart rate is the first step in setting up your training intensity zones. Your AeT defines the top of Zone 2—the aerobic base-building zone where you should do the vast majority of your endurance training. Without an accurate AeT, you are guessing at your intensities, and most athletes guess too high. The gold standard for determining AeT is a laboratory Gas Exchange Test or Metabolic Efficiency Test. But you do not need a lab. The nose breathing test is a simple, accessible method that works well for…