When it comes to endurance training, you’ve probably heard terms like aerobic capacity (VO₂ max) and aerobic threshold, but what do they actually mean? More importantly, how do they impact your performance and the way you should train? Whether you’re a runner, cyclist, CrossFitter, or just someone looking to improve overall endurance, understanding these two concepts can help you structure your workouts for maximum results.

What is Aerobic Capacity (VO₂ Max)?

Aerobic capacity, also known as VO₂ max, is the maximum amount of oxygen your body can use during intense exercise. Think of it as your body’s engine size—the bigger the engine, the more power you can produce. Athletes with a high VO₂ max can generate more energy aerobically, allowing them to perform at higher intensities before fatigue sets in.

How It Affects Training:

  • If your VO₂ max is low, you may struggle with high-intensity efforts or prolonged exertion.
  • To improve VO₂ max, focus on high-intensity interval training (HIIT), sprint intervals, hill sprints, or maximal-effort cardio workouts.
  • A higher VO₂ max helps increase your potential for speed, power, and overall endurance.

What is Aerobic Threshold (AeT)?

Your aerobic threshold is the highest intensity at which your body can still efficiently clear lactate and primarily use fat for energy. Once you exceed this point, your body starts relying more on carbohydrates, and fatigue builds up faster. If VO₂ max is your engine size, your aerobic threshold is your fuel efficiency—it determines how long you can sustain effort before needing to slow down or stop.

How It Affects Training:

  • If your aerobic threshold is low, you’ll fatigue quickly, even at moderate intensities.
  • To improve your aerobic threshold, focus on low-to-moderate intensity steady-state workouts (Zone 2 training, long slow runs, cycling, or rowing at 60-75% of max heart rate).
  • A higher aerobic threshold means you can sustain higher paces for longer without burning out—essential for marathoners, triathletes, and endurance athletes.

How This Impacts Your Training Plan

Both VO₂ max and aerobic threshold play essential roles in athletic performance, but they serve different purposes.

  • If your VO₂ max is high but your aerobic threshold is low, you can perform short bursts of high effort but struggle to maintain pace over time.
  • If your aerobic threshold is high but VO₂ max is low, you can sustain moderate efforts for long periods but lack the ability to push to higher intensities.
  • For well-rounded performance, balance your training with both steady-state aerobic work (to improve threshold) and high-intensity intervals (to raise VO₂ max).

Key Takeaways

✔ VO₂ max = Your engine size (how much power you can produce).
✔ Aerobic threshold = Your fuel efficiency (how long you can sustain effort before fatigue sets in).
✔ Train both to boost endurance, increase speed, and improve overall performance.

By understanding and targeting both aerobic capacity and aerobic threshold, you can train smarter and push your athletic performance to new levels. Whether you’re training for a marathon, a triathlon, or just improving your overall fitness, balancing these two elements will help you perform at your best!