Anaerobic Threshold (AT) Value Index: Explanation and Clinical Context The Anaerobic Threshold (AT) represents the exercise intensity at which lactate begins to accumulate in the blood, signaling a shift from predominantly aerobic to anaerobic metabolism.
AT Index is calculated using VO2 max and heart rate at AT, providing a relative measure of cardiovascular and metabolic efficiency during exercise.
Normal AT occurs around 50-70% of VO2 max in healthy adults. A lower AT indicates reduced aerobic capacity and early onset of fatigue, which can be seen in heart failure, cardiopulmonary disease, or deconditioning.
This tool helps clinicians, sports physicians, and cardiologists assess exercise tolerance, optimize training programs, and predict cardiovascular risk in patients undergoing cardiopulmonary exercise testing (CPET).
Reference:
Myers J, et al. "The Anaerobic Threshold and Cardiopulmonary Exercise Testing." Circulation. 2001;104:769–774. doi:10.1161/hc3101.093979