Maitohappokynnyksen

Maitohappokynnyksen, or lactate threshold, refers to the exercise intensity at which lactate begins to accumulate in the blood due to an imbalance between lactate production and clearance. It marks a shift from predominantly aerobic metabolism to greater dependence on anaerobic energy pathways as effort increases. In endurance physiology, the concept helps describe a practical upper limit for sustainable, high‑quality work.

The concept is often divided into two related thresholds. The first lactate threshold (LT1) corresponds to the initial rise in blood lactate above resting levels as exercise intensity increases. The second lactate threshold (LT2), sometimes called the lactate turn point, occurs when lactate begins to accumulate more rapidly and continuously with increasing intensity. In trained athletes LT2 is frequently near about 4 millimoles per liter, but there is substantial individual variation for both LT1 and LT2.

Assessment is usually performed in a laboratory with graded exercise testing and serial blood samples to measure lactate, or by using ventilatory thresholds as proxies. Field methods include estimating the lactate threshold from pacing or power data tied to lab results, or using the talk test as a rough indicator of a sustainable intensity. Reliability improves when testing is repeated under consistent conditions (nutrition, fatigue, temperature, and prior training influence measurements).

Importance for training and performance lies in its role as a key marker for endurance work. Training near or at the lactate threshold can improve the body’s ability to clear lactate and sustain higher intensities for longer. As such, many training plans use tempo or threshold workouts designed to elevate the lactate threshold, thereby increasing competitive endurance capacity.

---