What does high-intensity interval training (HIIT) involve?

High-intensity interval training (HIIT) is characterized by alternating periods of intense exercise with recovery or lower-intensity periods. This method leverages the benefits of pushing the body to its limits during short bursts of activity, followed by recovery intervals that allow for partial recuperation. This approach can efficiently improve cardiovascular fitness, speed, and overall endurance while burning calories.

The essence of HIIT is its focus on maximizing effort during the high-intensity intervals, which typically last from a few seconds to a few minutes, followed by a rest or active recovery phase. This cycle can be repeated several times, making HIIT a time-efficient workout choice that provides significant physical benefits.

In contrast, the other options describe different forms of exercise that do not align with the specific mechanics of HIIT. Long, steady-state cardio sessions focus on maintaining a consistent intensity rather than alternating intensities. Strength training with minimal recovery does not incorporate the high-intensity interval structure, and low-intensity workouts for an extended duration miss the hallmark intensity intervals inherent to HIIT. Therefore, the correct understanding of HIIT clearly aligns with the definition provided in the answer.