Anaerobic exercise is characterized by which of the following?

• A. High intensity and short duration
• B. Low intensity and long duration
• C. Slow, steady, moderate pace
• D. Requires continuous oxygen delivery

Answer: (A)

Anaerobic exercise uses energy systems that don’t rely on oxygen, so you can surge to a very high level of effort quickly, but only for a short time. At the start, the body mainly uses the ATP-PC system for instant energy, then glycolysis fuels a high-intensity effort for a little longer, until fatigue from limited ATP and lactate buildup stops you. That combination—very hard effort, short duration—fits anaerobic activity best. By contrast, activities that depend on oxygen delivery (aerobic) are typically lower in intensity and can be sustained longer, which is why the other descriptions don’t match anaerobic exercise.