Lactate shows how well you burn fat
Pro endurance athletes burned far more fat and made less lactate at the same workloads than moderately active people or people with metabolic syndrome.
What they studied
- Design
- Cross-sectional comparison
- Groups
- Professional endurance athletes · moderately active people · people with metabolic syndrome
- Test
- Graded exercise with blood lactate and indirect calorimetry
- Outcome
- Fat and carbohydrate burning at each workload
What they found
- Pro athletes burned significantly more fat than both other groups and had lower blood lactate at the same workloads.
- Within every group, lactate and fat burning moved in opposite directions (r = −0.92 to −0.98).
- Across all groups together the correlation was r = −0.76.
How strong is the evidence
Cross-sectional
What this design cannot tell us:
- Cross-sectional: it compares groups, it does not follow people as they train.
- Correlation between lactate and fat burning does not show cause.
What it means for your training
- This is the logic behind Zone 2: steady work just below the point where lactate starts to rise.
- A lactate test can find your Zone 2 and show whether your fat-burning capacity improves over time.
Our summary of the published abstract. Read the original paper for full details.