Lactate and training: Evidence-Based Supplement Guide

Lactate was once seen as a product of muscle running short of oxygen. According to a review of lactate shuttles, it is made and used continuously, even when oxygen is plentiful (PMID 19805739). Working muscle passes lactate to the heart, brain, liver and kidneys, where it serves as fuel, as material for making glucose, and as a signal (PMID 19805739). In a graded exercise test, blood lactate stays near resting levels at easy intensities and then rises steeply as effort climbs (PMID 19453206). A review located 25 different ways to define lactate thresholds along this curve, and most studies that tested them against endurance performance reported strong correlations (PMID 19453206). A shift of the whole curve indicates a change in endurance capacity (PMID 19453206). The number a test reports depends on how the test is run. In 17 trained cyclists, stage length and the calculation method changed the threshold found, and many traditional methods did not match the highest steady lactate effort (PMID 30059543). Professional endurance athletes burned more fat and had lower blood lactate than moderately active people during graded exercise (PMID 28623613). Most people training for health can use a simpler check. In 16 healthy volunteers, the point where speech first became difficult matched the ventilatory threshold on a treadmill and a bike (PMID 15354048).

1. **Use one protocol every time.** Keep stage length and the calculation method the same, because both change the threshold a test reports (PMID 30059543). 2. **Read the whole curve, not one number.** A shift of the curve is what indicates a change in endurance capacity (PMID 19453206). 3. **Use the talk test as a free check.** The point where speech first became difficult matched the ventilatory threshold (PMID 15354048). 4. **Compare like with like.** A threshold from one lab or device only compares with another measured the same way (PMID 30059543).

A lactate test describes fitness on the day it is run. Each stage of a graded test needs time for blood lactate to settle, and the method that matched best in trained cyclists used four-minute stages (PMID 30059543). Repeat tests with the same protocol so that a shift in the curve can be read as a change (PMID 19453206).

- **The protocol study tested 17 trained male cyclists**, so its best method may not transfer to other people or sports (PMID 30059543). - **The athlete comparison is cross-sectional**, so it shows the measures go together, not that one causes the other (PMID 28623613). - **The talk test study had 16 healthy volunteers** (PMID 15354048). - **The lactate shuttle review draws on cell, animal and human research** (PMID 19805739). - **This guide has not been reviewed by a clinician.** `reviewStatus` above says so.

- **A single lactate reading does not describe your health.** Thresholds depend on the protocol and the calculation method (PMID 30059543). - **Graded tests end in hard efforts.** The cycling study screened participants before testing (PMID 30059543), and anyone with a long-term health condition should check with a clinician first.

No ingredient is linked from this guide. It covers how lactate behaves and how it is tested, and it does not point to a product.

| PMID | Title | | --- | --- | | 19805739 | "Cell-cell and intracellular lactate shuttles" | | 19453206 | "Lactate threshold concepts: how valid are they?" | | 30059543 | "Manipulating graded exercise test variables affects the validity of the lactate threshold and VO2peak" | | 28623613 | "Assessment of Metabolic Flexibility by Means of Measuring Blood Lactate, Fat, and Carbohydrate Oxidation Responses to Exercise in Professional Endurance Athletes and Less-Fit Individuals" | | 15354048 | "Consistency of the talk test for exercise prescription" |