How long should an aerobic interval last for optimal intensity?

For optimal intensity in aerobic intervals, the duration of 30 seconds to a few minutes is ideal because this range allows individuals to achieve a sufficient level of effort that elevates the heart rate and engages the cardiovascular system effectively. This duration strikes a balance that promotes both aerobic capacity and metabolic conditioning, enabling participants to push their intensity throughout the interval without leading to excessive fatigue too quickly.

Shorter intervals, such as 10 seconds, do not provide enough time for the body to engage in prolonged aerobic metabolism and may instead rely more on anaerobic energy systems. Meanwhile, durations that extend to 5-10 minutes or 15-20 minutes may hinder the ability to maintain high intensity, as they are typically associated with moderate-intensity steady-state cardio rather than the interval training approach that aims for bursts of high intensity followed by rest or low-intensity recovery. Thus, the chosen range of 30 seconds to a few minutes is most effective for maximizing both intensity and the associated benefits of aerobic interval training.