s2/e08 The Science of "Aerobic" & "Anaerobic" Running with Coach Laura Norris (@lauranorrisrunning)

Energy Systems

Laura Norris, a certified running coach, explains the fundamental differences between aerobic and anaerobic energy systems in the body. Aerobic metabolism uses oxygen to break down carbohydrates, fats, and proteins to produce ATP, the energy currency for muscles, while anaerobic metabolism relies on glycolysis or phosphocreatine pathways without oxygen 1. She emphasizes that aerobic energy is lower power but higher capacity, whereas anaerobic energy is high power but low capacity, suitable for short bursts of activity 2.

Aerobic is lower power, higher capacity, and anaerobic is high power, low capacity.

--- Laura Norris

Understanding these systems helps runners optimize their training by targeting specific adaptations for efficiency and endurance.

   

Fuel Sources

The body uses different fuel sources for aerobic and anaerobic energy production, impacting performance. Laura Norris explains that at lower intensities, the body primarily burns fatty acids, sparing glycogen for higher intensities 3. As intensity increases, carbohydrate usage rises, eventually leading to anaerobic energy production, which is fast and explosive but limited in duration 4.

Your body produces most of its energy in an aerobic, meaning with oxygen, way.

--- Elisabeth Scott

This understanding helps athletes manage energy efficiently during training and competition.

   

VO2 Max

VO2 max, the maximum rate of oxygen uptake, is often misunderstood in its role in performance. Laura Norris clarifies that while VO2 max is a good indicator of cardiovascular health, it plateaus early in training and is not the sole predictor of performance 5. Many runners mistakenly rely on devices like Garmin for VO2 max readings, which are not accurate without lab testing 6.

If you have a high one, that doesn't mean anything, and if you have a low one, that might make you feel bad and also still might not be true.

--- Elisabeth Scott

Instead, focusing on improving lactate threshold and running economy can lead to better performance outcomes.