Can Strength Training Be Aerobic?
Strength Training ≠ Anaerobic Exercise
Just like running and swimming, strength training is a form of exercise—not a single energy system. Aerobic and anaerobic refer to the body's energy supply methods, and these are independent classification dimensions. In exercise science, any prolonged, low-to-moderate intensity activity engages the aerobic energy system, regardless of whether the external form is resistance or endurance training.
Why Strength Training Also Engages the Aerobic System
When performing strength training with 12RM or lighter loads, muscles must sustain contraction to overcome resistance, keeping heart rate within the aerobic endurance zone (60%-70% of max HR). At this point, the body primarily relies on aerobic metabolism, with fatty acid and glycogen oxidation providing most of the energy.
Conversely, when using 1-3RM loads for maximum strength or power training (such as deadlifts or clean and jerk), the exercise duration is brief while intensity is extremely high, engaging predominantly anaerobic energy systems. Research shows that strength training, especially when combined with aerobic training, can effectively improve cardiorespiratory fitness (VO₂max)—meaning strength training is not only a means of building muscle but also an important way to enhance cardiovascular health.
Load Selection Matters
| Training Type | Load Range | Primary Energy System |
|---|---|---|
| Maximum Strength | 1-3RM | Anaerobic |
| Power | 1-5RM, rapid concentric contraction | Anaerobic |
| Muscle Hypertrophy | 6-12RM | Mixed aerobic + anaerobic |
| Muscular Endurance | 12RM+ | Primarily aerobic |
This means that for the same person, performing 15 reps with a light dumbbell curl versus 5 reps with a heavy dumbbell curl—both "strength training"—engages completely different energy systems.
The Relationship Between Exercise Type and Aerobic/Anaerobic
It's important to clarify that strength training, like running and swimming, is an exercise form; aerobic and anaerobic are classifications of energy systems. These are independent dimensions that are often conflated in everyday language, though exercise science makes clear distinctions.
Similar examples include:
- Sprinting = anaerobic exercise
- Marathon running = aerobic exercise
- Running isn't necessarily "aerobic"—it depends on intensity and duration
How Does PeakWatch Determine Aerobic vs. Anaerobic?
In exercise physiology, the distinction between aerobic and anaerobic is not determined by exercise type, but by the body's energy supply method during activity. PeakWatch monitors heart rate during training and maps it to different heart rate zones:
- When heart rate is in the aerobic endurance zone (60%-70% of max HR), the body primarily uses aerobic metabolism
- When heart rate enters the anaerobic threshold zone (above 80% of max HR), anaerobic energy contribution increases
Therefore, even in strength training, if the tempo is slow with longer rest periods between sets, causing heart rate to stay in the aerobic zone, the system will classify it as aerobic-dominant training. Conversely, in high-intensity circuit training or exercises with many rapid concentric contractions where heart rate spikes into the anaerobic zone, the system will reflect this accurately.
References
American College of Sports Medicine. (2023). ACSM's Guidelines for Exercise Testing and Prescription (11th ed.). Lippincott Williams & Wilkins.
This article is for health education purposes only and is not intended as medical diagnosis or treatment. Please consult a professional physician if you experience any discomfort.