Running: What does "aerobic" and "anaerobic threshold" mean?

The term anaerobic threshold is the most important characteristic for determining current performance.

The anaerobic threshold or often also referred to as "aerobic-anaerobic threshold" indicates the load range in which the current oxygen consumption can just be covered by the oxygen supply.

The anaerobic threshold (= ANS) is of great importance in running or endurance sports in general, because an upward shift of the anaerobic threshold leads to an improvement in performance. Simply put, at a higher anaerobic threshold, you can run a faster pace consistently for a long time.

When do I run aerobically and when anaerobically?

Aerobic is the range in which sufficient oxygen is available to our body for aerobic energy production. Runs in the aerobic range can be sustained for a very long time. The typical base runs in training are mostly in the aerobic range. In addition to the anaerobic threshold, there is also an aerobic threshold in the training literature. The area between the aerobic threshold and the anaerobic threshold is defined as the aerobic-anaerobic transition area - in this area the lactate level in the blood increases.

That is, the three ranges are divided as follows:

• aerobic range (LT1): up to 2 mmol/l*.
• aerobic-anaerobic transition range: 2 - 4 mmol/l*.
• anaerobic range (LT2): above 4 mmol/l*

* mmol/l = blood lactate concentration in millimoles per liter. LT = lactate threshold

Note: The "mmol/l figures" are "generally defined" ranges. Actual ranges may vary greatly from person to person. For example, the anaerobic threshold may not be exceeded until 5 mmol/l. Authors have also defined the transition range between aerobic threshold and anaerobic threshold with varying breadth in various scientific publications. Hans-Hermann Dickhuth, in the running book "Einführung in die Sport- und Leistungsmedizin" (Introduction to Sports and Performance Medicine), stated that the anaerobic threshold is reached from 1.5 mmol/l above the aerobic threshold. In this case, with an aerobic threshold of 2 mmol/l, the anaerobic threshold would be reached at 3.5 mmol/l.

Running in the anaerobic zone

If the anaerobic threshold is exceeded, then the body no longer has enough oxygen available. Now the decomposition product lactic acid (= lactate) comes into play, which must be broken down. In the aerobic-anaerobic transition zone, lactate formation increases steadily, but the body can still break down the lactate at the same time. The running speed can therefore be maintained. This is the range in which you run, for example, in long competitions such as marathons.

However, when the anaerobic threshold is exceeded, more lactate is produced than can be broken down by the body at the same time. The result is over-acidification of the muscles and thus a drop in performance. In short races, such as a 10-kilometer road race, the anaerobic threshold is exceeded in the course of the race. Due to the short race distance, however, this does not yet lead to a drop in performance, since the finish line is reached before the delayed consequences of the excess lactate become noticeable. In middle-distance races over 800 meters or 1,500 meters, athletes sometimes even reach lactate values of well over 10 mmol/l

Calculate anaerobic threshold

How do I find my anaerobic threshold?

Generally defined, the anaerobic threshold is reached at a blood lactate concentration above 4 mmol/l. As already mentioned, this value can vary greatly.

For an actually accurate determination of the anaerobic threshold, a lactate measurement must be performed. A lactate test involves running on a 400-meter track (or alternatively a treadmill) and gradually increasing the speed. For well-trained runners, 2,000-meter runs have proven to be effective. After each 2,000-meter run, the lactate is measured by means of a prick in the ear or finger and the resulting blood sample. The runner then completes another 2,000-meter run at an increased pace. The pace during the first run should be as slow as possible so that the lactate measurement does not exceed the aerobic threshold already during the first run, otherwise a meaningful evaluation of the data would not be possible or would be difficult. After each 2,000-meter run, the runner's lactate is measured. The lactate test continues until the maximum workload is reached, i.e. ideally when the runner reaches a level at which he or she can no longer run the full distance (in this range, the lactate value is already well above the anaerobic threshold).

Alternative: Breathing gas analysis

The aerobic threshold and the anaerobic threshold can also be determined by a breathing gas analysis. This analysis uses a mask to measure the CO2 content and the oxygen uptake during the breathing process. In the context of respiratory gas analysis, the thresholds are defined as VT1 (aerobic) and VT2 (anaerobic).

Note: The anaerobic threshold is approximately 88 - 93 percent of the maximum heart rate. So if you know your maximum heart rate, you can calculate the anaerobic threshold "approximately" without a lactate test - but not nearly as accurately as a lactate test. Running watches can also automatically calculate VO2max based on this parameter.

Simple alternative: Calculate the anaerobic threshold based on the maximum heart rate.

The following formula is often used: 0.94 * max. Hf - 7

Example: A runner with a maximum heart rate of 200: 0,94 * 200 - 7 = 181

Attention: In contrast to the lactate test much more inaccurate. In this case it is assumed that the anaerobic threshold is at about 90% of the maximum heart rate. However, two athletes with an identical maximum heart rate can differ significantly in their current performance. Therefore, we do not recommend the use of this formula for training control.

What influence factor does the pulse have?

With every lactate measurement, the runner's heart rate should also be recorded continuously. Only then is a targeted training plan possible, in which the individual training areas are divided into heart rate zones. It is absolutely necessary to calculate the maximum heart rate as accurately as possible. For this purpose, one takes the maximum value reached during the lactate test, which is usually reached towards the end of the last stage.

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Then the heart rate ranges for the individual training areas can be defined. In the GA1 range (basic endurance 1), running is done with a pulse of 65 to 80% of the maximum heart rate. If a maximum heart rate of 200 was determined for the runner, then he would have to run his basic runs with a heart rate of 130 - 160. Thanks to the lactate test and the lactate values, these zones can be defined even more precisely by the trainer

Improve aerobic and anaerobic threshold

How can I raise the anaerobic threshold?

Quite simply: By regularly running at a pace that is in the anaerobic threshold zone or just below or above it. These are for example tempo runs, interval training but also short competitions.

How can I raise the aerobic threshold?

The aerobic threshold, on the other hand, can be improved by less intensive training, i.e. the typical basic runs in a heart rate range of approx. 65 - 85 percent of the maximum heart rate.

How do I train anaerobically?

Efficient methods to improve anaerobic threshold are tempo runs or classic interval training. Tempo running is also defined as threshold training:

What is anaerobic threshold training?

Threshold training is one of the most efficient methods of shifting the anaerobic threshold upwards. Through such training, the runner with hyperacidity (i.e. high lactate formation) learns to maintain the pace longer, moreover, threshold training serves to shift the anaerobic threshold upwards. This means that the anaerobic threshold is only exceeded at a higher pace.

Threshold training involves running as long as possible at the anaerobic threshold (= lactate steady-state) or just below it. Therefore, it is essential to know in advance in which speed range the individual anaerobic threshold is located. Only then is efficient threshold training possible.

Due to the high intensity, threshold training should not be integrated too frequently into the training.

These are the most important characteristics of threshold training:

• Tempo in the range at the anaerobic threshold or just below it.
• Possible as tempo runs (30 - 60 minutes; marathon runners also longer)
• Possible as interval training (alternation of load and short recovery)
• Maximum 20 % of the training volume (world-class marathon runners train up to 20 % of the volume at the anaerobic threshold)
• Active or passive regeneration on the day after threshold training

Quick fact to conclude: lactate has a half-life of 15 to 20 minutes. Half-life is the amount of time it takes for the value to be cut in half. So if you reach a lactate level of 8 mmol/l during a high-intensity workout, it takes your body up to 20 minutes to break down the lactate again so that you get below the aerobic-anaerobic threshold. That's why we feel really flat for some time after very intense tempo runs.

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