Hello to all running enthusiasts!
We often focus on our finish time or pace per kilometer, but how well do we truly understand what our body is doing while we run? Today, I’ll guide you through three key parameters—VO₂max, lactate threshold, and HRV—that will help you deeply understand your physiology and optimize your training to reach ever-higher levels of performance.
Indice
VO₂max: Your Aerobic Engine at Full Power
Imagine your body as an engine: VO₂max is its ability to draw in oxygen from the environment, transport it, and use it to produce energy. It’s measured in milliliters of oxygen per kilogram of body weight per minute (ml O₂ kg⁻¹ min⁻¹) and is a fundamental indicator of your cardiovascular endurance. The higher your VO₂max, the more energy you can produce, and the longer you can sustain prolonged effort.
How is it measured?
The most accurate assessment is done in a lab using a specific test that simulates running on a treadmill (or cycling), monitoring the oxygen you inhale and exhale. There are also field tests—less precise but still useful—such as the mile test, the Cooper test, or the 5-lap track test.
What does it mean?
A low value (below 50 ml O₂ kg⁻¹ min⁻¹) indicates limited aerobic fitness, while values above 60 ml O₂ kg⁻¹ min⁻¹ are typical of high-level athletes. A range of about 50–60 ml O₂ kg⁻¹ min⁻¹ is common among runners with a solid training base.
How to improve it?
Interval training, tempo runs, hill repeats, high-intensity cycling, and—above all—well-planned recovery (sleep, nutrition, stretching) are the main tools for increasing VO₂max. Keep in mind that genetics and age play a major role, so focus on what you can control: your effort and consistency.
Lactate Threshold: The Border Between Aerobic and Anaerobic
During a run, your body uses both aerobic (with oxygen) and anaerobic (without oxygen) processes to produce energy. The lactate threshold is the point at which lactate accumulation in the blood surpasses your body’s ability to clear it. Crossing this threshold leads to a drop in performance and an increased feeling of fatigue.
Why is it important?
The lactate threshold is strongly correlated with your ability to sustain high-intensity effort for a prolonged time—around 85–90% of your VO₂max.
How is it assessed?
In the lab, a progressive test is performed while monitoring blood lactate levels. Alternatively, it can be estimated through a 4-minute running test or using heart rate data.
What does it tell you?
A low lactate threshold limits your ability to run at high speeds, while a high threshold allows you to maintain a strong pace for longer.
How to train it?
Tempo runs, high-intensity interval training, threshold-zone fartlek, and solid muscular endurance work are the most effective strategies for improving your lactate threshold.
HRV: The Harmony of Your Nervous System
Heart Rate Variability (HRV) measures the variations between heartbeats. It can be a valuable indicator of the health of your autonomic nervous system (ANS), which regulates involuntary functions like heart rate, breathing, and digestion.
Why is it reliable?
High HRV reflects a flexible, well-balanced ANS, while low HRV may signal fatigue, chronic stress, and an increased risk of overtraining.
How is it measured?
You can monitor HRV through a smartwatch or chest strap and analyze it with dedicated software. Ideally, measure it in the morning, at rest.
How to interpret the results?
An RMSSD value (a specific HRV indicator) above 40 ms suggests good resilience, while values below 20 ms may indicate chronic fatigue.
How to use it?
HRV can guide your training plan: high HRV suggests a hard session, while low HRV calls for recovery. Tracking trends over time reveals how stress and training load influence your body. Remember that environmental factors and sleep quality affect HRV, so always take them into account.
Combining Data to Optimize Your Training
- Assess your baseline: Measure VO₂, threshold, and HRV before each training cycle.
- Define your pace zones: Use your lactate threshold (and VO₂ if available) to establish intensity zones.
- Structure your training: Alternate phases of building (volume and intensity), peaking (performance maximization), and recovery (tapering).
- Stay reactive: Use HRV to adjust your plan based on how you feel that day.
- Listen to your body: Combine physiological data with perceived effort and sleep quality.
- Experiment and iterate: Each training cycle should be followed by review, adjustment, and new testing.