What is an example of a high intensity aerobic activity?

Cycling is considered a high-intensity aerobic activity because it can significantly elevate your heart rate while engaging multiple muscle groups simultaneously. When performed at a fast pace or on a challenging terrain, cycling pushes the cardiovascular system, improving endurance and stamina. This intensity level typically allows for substantial caloric expenditure, which is a key characteristic of aerobic exercise that focuses on improving overall fitness.

In contrast, walking is generally a lower-intensity activity that may not sufficiently elevate heart rates for an aerobic workout, depending on the speed and duration. Playing with children can vary greatly in intensity but often involves sporadic bursts rather than sustained, high-intensity effort. Gardening, while beneficial for flexibility and moderate activity, usually doesn't reach the levels required for high-intensity aerobic benefits. Therefore, cycling stands out as the best example of high-intensity aerobic activity among the options provided.