At approximately what percentage of maximum heart rate does the aerobic threshold occur?

The aerobic threshold is a significant marker in exercise physiology that indicates the point at which the body shifts from primarily using fat as a fuel source to increasingly relying on carbohydrates. This transition occurs as exercise intensity increases and usually occurs at around 65% of maximum heart rate (MHR) for trained individuals.

At this intensity, the body can still operate efficiently, utilizing oxygen to produce energy aerobically, which is crucial for sustained endurance activities. It reflects an optimal level where the aerobic system is effectively engaged without the onset of significant lactic acid accumulation, making it important for endurance training and improving cardiovascular fitness.

Maintaining exercise around this percentage allows individuals to build a strong aerobic base, which is essential for various forms of competitive and non-competitive endurance activities.