Metabolic thresholds refer to specific points during exercise where the body shifts from using primarily fat for energy to relying more on carbohydrates. This transition occurs as exercise intensity increases, leading to changes in how the body metabolizes fuel. Understanding these thresholds helps athletes optimize their training and performance. There are two main types of metabolic thresholds: the lactate threshold and the aerobic threshold. The lactate threshold is the point at which lactic acid starts to accumulate in the blood, indicating a shift to anaerobic metabolism. The aerobic threshold is the level of exercise intensity at which the body can still efficiently use oxygen for energy.