Lactate testing and lactate threshold: what the test shows

Aerobic means with oxygen, and anaerobic means without oxygen. NHI describes that the body produces lactate when the oxygen supply does not keep up with demand, and that this causes fatigue and limits how long high intensity can be sustained [2].

How well lactate is tolerated varies between people and depends, among other things, on the composition of muscle fibres [2]. Lactate can be measured in the blood, and in a test a small sample is usually taken after each load step.

With increasing load there are two breakpoints in the lactate curve. One is the intensity at which lactate starts to rise above resting level. The other is the maximal lactate steady state, the highest intensity at which production and removal of lactate are still in balance [3].

There is no single common definition. A review in the journal Sports Medicine identified 25 different threshold concepts, which can be grouped into fixed lactate concentrations, the first rise above resting level, and methods that try to find the maximal lactate steady state [3]. The fixed limit of 4 mmol/L originates from a research group in Cologne in the 1970s and 1980s [4]. Which value a test reports therefore depends on the method used.

A lactate profile is carried out with load steps of five minutes with increasing load. At the test laboratory of the University of South-Eastern Norway four to eight steps are used, with a 5 to 10 minute warm-up and 30 to 60 seconds of rest between the steps, and the whole test takes 30 to 45 minutes [1]. The test ends just above the threshold, so you do not have to be tested to exhaustion [1].

At every step oxygen uptake, heart rate, blood lactate concentration and perceived exertion are recorded [1]. A lactate profile and a VO2 max test can be done on the same day. The lactate profile is then done first, followed by about ten minutes of rest before the VO2 max test [1].

The test laboratory describes that the results are used to estimate the lactate threshold and related values such as heart rate, speed and watts. They are also used to set intensity zones with higher precision, to show how physiological variables change with increasing load and to follow development over time [1].

Intensity zones can be compared with the more general heart rate zones described by NHI, where endurance training is described at 50 to 85 percent of maximal heart rate [2]. A measurement gives individual values instead of average estimates.

In the review in Sports Medicine, most of 32 studies comparing lactate thresholds with endurance performance found strong linear associations, particularly for running. Some thresholds can also estimate the maximal lactate steady state, but the variation between threshold and this value in the individual was rarely reported [3].

The values should therefore be read as estimates. A threshold is first and foremost a tool for comparing your own tests over time under similar conditions, and it does not replace an assessment of how the training feels.

The test laboratory recommends that you do not do a hard training session the day before, have your last meal at least one hour before the test and avoid caffeine, snuff and smoking during the last four hours. You should arrive rested and avoid testing in periods of high training load [1]. If you have a known illness or are unsure whether you should exert yourself hard, it is sensible to discuss it with your doctor first.

At the Kondisjonsklinikken at Dr.Dropin Bislett the lactate profile is carried out by running several steps with increasing load on a treadmill. After each step a small sample is taken from the finger to measure lactate. The values for lactate, heart rate and speed are combined into a lactate curve that is used to set heart rate and speed zones. You get a review of the results. The lactate profile can be combined with a VO2 max test in the same visit.

What is the lactate threshold?

The lactate threshold is the intensity at which blood lactate starts to rise above resting level, or another defined point on the lactate curve. There are many different methods, and the value depends on which one is used [3].

What is the difference between a lactate profile and a VO2 max test?

The VO2 max test goes to exhaustion and gives a fitness value and maximal heart rate. The lactate profile ends just above the threshold and is used to estimate the lactate threshold and set intensity zones [1].

Do I have to be tested to exhaustion in a lactate profile?

No. The test ends at an intensity just above your threshold [1].

How long does a lactate profile take?

At the test laboratory of the University of South-Eastern Norway the whole test takes 30 to 45 minutes including warm-up [1]. The time needed may differ somewhat at other test sites.

Can a lactate profile and a VO2 max test be done on the same day?

Yes. The lactate profile is done first, and after about ten minutes of rest the VO2 max test follows [1].

You can read more about the Kondisjonsklinikken and about the VO2 max test. You can find more articles in the overview of articles.

This article was written by Dr.Dropin Fysikalske and is based on the sources listed below. It gives general information and does not replace an examination by a healthcare professional.

The websites were accessed and read on 22 October 2026.

1. Idrettsfysiologisk testlaboratorium, campus Bø (Sports physiology test laboratory, campus Bø). University of South-Eastern Norway (USN). Published 26 April 2018, last modified 9 April 2026. Link

2. Kvam M. Aerob og anaerob trening (Aerobic and anaerobic training). NHI.no. Published 10 September 2013, last updated 15 January 2020. Link

3. Faude O, Kindermann W, Meyer T. Lactate threshold concepts: how valid are they? Sports Med. 2009;39(6):469-490. doi:10.2165/00007256-200939060-00003. Link

4. Wackerhage H, Gehlert S, Schulz H, Weber S, Ring-Dimitriou S, Heine O. Lactate thresholds and the simulation of human energy metabolism: contributions by the Cologne Sports Medicine Group in the 1970s and 1980s. Front Physiol. 2022;13. doi:10.3389/fphys.2022.899670. Link