Lactate threshold is the point at which lactate is produced and accumulates in the blood at a faster rate than it can be removed, which leads to fatigue. Threshold training is designed to raise this point, enabling you to run faster for longer.
When we exercise, we break down glucose to create energy. Lactate and hydrogen ions are produced as a part of this process and enter the bloodstream. At slower paces, your body clears these by-products (known as buffering) with ease and uses lactate as an energy source. As you run harder, these by-products increase in your blood above their baseline – this is called lactate threshold.
Lactate is generally measured in millimoles per litre (mmol/L) and lactate threshold usually occurs around 2mmol/L. If you continue to increase running intensity, your body’s ability to clear and reuse lactate can’t keep pace with the rate at which it’s being produced – this is your lactate turn point. Beyond this, hydrogen ions and lactate rapidly increase in your blood. The increase in hydrogen ions lowers the pH level of your blood, making it more acidic. This reduces your muscles’ ability to contract, slowing you down. This point often occurs around 4mmol/L of lactate. So while lactate itself does not cause fatigue, we can use it as a proxy measurement for the other changes taking place that do limit your performance.
How does threshold training improve performance?
Many coaches, physiologists and athletes believe training just below, on or above your lactate turnpoint is a key way to improve it. Famous examples are Paula Radcliffe and Norway’s Ingebrigtsen brothers. This involves running a range of paces that fall between your lactate threshold (from around marathon pace) up to just beyond your lactate turnpoint (up to about 10K pace).
However, some coaches and athletes eschew the threshold model of training in favour of other approaches. You may be familiar with the concept of polarised training, where a high percentage of training (up to 80%) is spent at low intensities, with the rest run at the lactate turnpoint or above, steering clear of the middle ground that much of threshold training can fall into.
What works for you must be based on your individual training history and circumstances, but I have found threshold-based training has helped many of the athletes I’ve coached over the past 12 years. It’s not a magic bullet, and it needs to be mixed with good recovery and a broader sensible training mix, but if you aren’t including threshold work in your sessions, you could be missing out on some important development as a runner.
Is tempo pace the same as threshold pace?
Terminology in running can be confusing. If you're wondering about the differences between threshold and tempo running, I'm afraid I can't give a straight answer. For some runner and coaches, tempo running refers to longer efforts at a slightly lower intensity, which you might be able to hold for two to three hours in a race (closer to lactate threshold).
For others, it's a run at a pace slightly stronger than lactate turnpoint, closer to 30 to 40-minute race pace, while some use tempo running and threshold running interchangeably.
Sometimes, it's better to just say what you mean: for example, run for a pace you could hold for 40 to 60 minutes in a race, run at this heart rate, ect. Or can you make it even simpler – easy, steady, strong, hard, for example.
Splitting threshold sessions into long efforts with short, easy or steady recoveries can allow you to extend the amount of time you spend at threshold effort, or run slightly quicker while keeping your intensity under control. For example, 6 x 5 mins with 60-sec easy recoveries, or 3 x 10-15 mins with 2-min easy-to-steady recoveries.
Spice it up: Split sessions allow you to vary your paces. Try 12 mins, 10 mins, 8 mins and 4 mins, with 90-sec recoveries. Start at a pace you could hold for 60 to 70 mins in a race and work down to 30 to 45-min race pace.
