the point just below which the body’s energy production switches from aerobic to anaerobic. Interval training raises the heart rate at which the threshold is crossed. Also called the lactate threshold (LT). Working close to this intensity enhances endurance as well as pacing.
This intensity level is known as the lactate threshold and is roughly 80–90% of VO₂ max in trained athletes. Below the effort, the body is efficient with oxygen when creating energy; above the effort, the body is forced to use increased anaerobic means, and lactate accumulation results in fatigue. Train consistently at or slightly below the anaerobic threshold—for example, doing 20- to 40-minute tempo runs or longer bicycle intervals—to cause the body to flush out lactate with increased efficiency, increasing the threshold. Your threshold can be determined with blood-lactate testing or estimated with an exercise test (the pace that can be maintained for an hour). Having an awareness of your anaerobic threshold is useful when racing for longer distances in order to identify a pace that can be maintained for time trials, long runs, or climbing steep mountains, so that you are able to go fast enough without exhausting yourself prematurely. Testing repeatedly and tracking progress allows athletes to view their improvement and make adjustments in their training regimens.
