In physiology terms, lactate threshold is the fastest running speed at which your blood lactate levels remain at a steady state. Any faster and lactate begins to accumulate in your blood more rapidly.
Lactate and hydrogen ions are by-products of anaerobic metabolism and are released into the muscles when you start to exercise at a higher intensity. Hydrogen ions make the muscles more acidic and interfere with some of the enzymes responsible for making energy, which means that we start to fatigue pretty quickly in their presence.
Running at lactate threshold pace however, improves your body's ability to buffer the lactate and therefore delays fatigue, which in essence enables you to run at a faster pace for longer.
Running at lactate threshold pace however, improves your body's ability to buffer the lactate and therefore delays fatigue...
So, the science is nice, but how do you know what your threshold pace is?
The simplest way to determine your threshold pace is by feel. A threshold run shouldn't be an ‘eyeballs out’ effort, but rather at a 'comfortably hard' pace. Remember that the purpose is to stress your body's ability to clear lactate, not to over stress that capability. Therefore the key is not to run too hard during this type of workout because you won't achieve the desired physiological effect. A true threshold run shouldn't feel really hard, that's what racing is for.
To ensure that you're not overcooking your threshold runs, you can use these methods to monitor your intensity:
- The talk test: You should be able to say three or four word sentences but not more. Ask yourself aloud: "Is this pace right?" and "Am I in control?"
- Perceived exertion: If you were to gauge your effort on a scale from one to 10 – where a steady run would be around a five and a race would be close to 10 – then threshold effort should rank at an eight.
If you're the kind of runner who likes data then you can also determine your lactate threshold through physiological testing. A treadmill test where blood lactate is sampled at increasing speeds will give you an indication of the pace at which you hit lactate threshold and your heart rate at this pace.
How to do threshold running
The beauty of threshold running is that it can be done in a number of ways. Traditionally threshold runs are done as a continuous, sustained effort. You can start with 10-15 minutes in total and increase the total time as you progress, progressing to a maximum of 35-40 minutes. This could be done as part of a steady run. For example, 15 minutes steady running followed by 15 minutes threshold running, followed by another 15 minutes of steady running.
However, if you are new to threshold running or want to ensure that you maintain the correct pace, then you can break the total time into chunks and run threshold blocks with a short recovery. For example, 4 x 5 mins with two minutes jog recovery.
Many exercise physiologists and coaches argue that lactate threshold isn't an exact science so the best way to ensure that you hit the correct pace is by using a progression run.
Many exercise physiologists and coaches argue that lactate threshold isn't an exact science so the best way to ensure that you hit the correct pace is by using a progression run. Start at a pace that is slightly slower than your perceived threshold pace and gradually wind the pace up until you feel as if you are running at threshold effort.
Use the talk test or the perceived exertion scale to gauge your effort. If you are able to, increase the pace slightly further for the last part of the run so that you are running just above threshold effort. Be strict with yourself though and don't get too carried away. You shouldn't be pushing really hard. The idea of this workout is that somewhere during the run you will hit your true lactate threshold, and working just below and just above it will help to push it up to faster speeds.