Aerobic threshold is the intensity of exercise at which the body switches from mainly using fat to mostly carbohydrates as a fuel source.
The aerobic threshold is usually expressed as a percentage of the maximum heart rate (HRmax) or the maximum oxygen uptake (VO2max). Depending on the individual and the sport, the aerobic threshold is typically between 50% and 75% of HRmax or VO2max.
The term aerobic threshold comes from the word aerobic, which means requiring oxygen, and the word threshold, which means the point at which something changes. The aerobic threshold is determined by the balance between the production and clearance of lactate, a by-product of anaerobic metabolism.
The aerobic threshold is when lactate accumulates in the blood, causing an increase in ventilation and a shift from fat to carbohydrate oxidation.
Some synonyms or related terms for aerobic threshold are:
- Fat-burning zone
An example of an aerobic threshold workout is a steady-state climb at a tempo pace for 30 to 45 minutes, keeping the heart rate within the aerobic threshold zone.
Alex Lee is the founder and editor-at-large of Mr. Mamil. Coming from a professional engineering background, he breaks down technical cycling nuances into an easy-to-understand and digestible format here.
He has been riding road bikes actively for the past 12 years and started racing competitively in the senior category during the summer recently.