Lactate threshold (LT) is a common endurance training term. Athletes from all endurance sports have at least a passing interest in their lactate threshold and often want to improve it. For many, the lactate threshold is seen as the key to running, cycling, swimming, etc., further and faster before fatigue sets in. 

But what is the lactate threshold, and how can you improve yours? Keep reading to find out!

What is Lactate Threshold?

Lactate is a substance produced in your body during physical exercise. It is a by-product of glucose utilization by muscle cells. Large amounts of lactate cause a reduction of muscle pH, resulting in acidosis. An acidic environment reduces muscle contractility and lowers force production. If lactate levels get too high, you’ll be forced to stop and rest.

In low-intensity activities and workouts, lactate is produced in minimal amounts, and your body can clear it faster than it is made. Subsequently, lactate levels remain low and have no impact on your performance. Examples of this type of activity include walking and easy jogging.

However, as exercise intensity levels increase, so do your lactate levels. The longer and harder you exercise, the more lactate is produced, and lactate begins to accumulate in your blood. This is called OBLA – the onset of blood lactate.

If lactate gets too high, fatigue sets in, and you’ll have to reduce the intensity of your activity or stop completely to allow levels to fall. Once lactate levels are low enough, you will be able to recommence exercising. Depending on how much lactate we’re talking about, this could take a few minutes to several hours.

Your lactate threshold is the highest level of sustainable physical exercise before lactate reaches a critical level. Exceeding your lactate threshold means lactate is produced faster than your body can clear it. In running terms, your lactate threshold is your fastest sustainable pace for something like a 5k. 

Improving your lactate threshold means delaying the point at which lactate levels start to rise uncontrollably. A higher lactate threshold means you’ll be able to exercise harder and longer before increasing levels of lactate force you to stop.

Some people are genetically blessed with a higher-than-average lactate threshold. However, training can also help slow the rise in blood lactate levels and improve your body’s ability to clear it.

How To Estimate Your Current Lactate Threshold 

If you are going to train to improve something, it’s worth doing a before-and-after test. This will allow you to identify your starting point and see how effective your training has been. 

Lactate testing is best done in a laboratory setting and by taking blood samples to measure blood lactate levels. However, such tests can be expensive, time-consuming, and are not readily available. 

The good news is that you can estimate your current lactate threshold using a simple DIY assessment. All you need is a heart rate monitor and an app for your data. Some activity watches also have built-in LT tests. 

You can do this test by running, cycling, or using any cardio machine in the gym. However, you should test your LT using the activity you want to improve. So, if you are a runner, you should do a running-based LT test.

Follow these steps to estimate your lactate threshold: 

1. Warm up for 10 minutes. Increase your pace gradually so that you finish feeling warm but not tired. Rest for five minutes but keep moving so you don’t start to cool down. 
2. Next, do a 30-minute time trial at your highest sustainable pace. Use the first ten minutes to build up and fine-tune your speed, and then hang on for the remaining 20 minutes. Ideally, you should hit the lap button on your heart rate monitor to separate your ten-minute build-up phase from the main part of the test. This will make analyzing your results much easier. 
3. After 30 minutes, stop your heart rate monitor and cool down for a few minutes. This is critical after a near-maximal effort workout if you want to avoid muscle soreness and recover faster. 
4. Upload and view your results. Your estimated lactate threshold is your average heart rate for the last 20 minutes of your test. Additionally, your average speed for those last 20 minutes is your lactate threshold pace. 

Armed with your estimated lactate threshold heart rate and pace, you can measure improvements and also use these figures when programming workouts to improve your LT. It’s also worth noting that your LT is usually around 85-90 percent of your maximum heart rate, but this can vary between athletes. Less fit individuals usually have a lower lactate threshold heart rate.

Workouts for Improving Your Lactate Threshold

The underlying principle of effective training is specificity. This means your workouts must match your training goal. So, if you want to improve your lactate threshold, some of your workouts must be near or at lactate threshold pace.

However, it would be a mistake to do all your workouts at your lactate threshold, as such high-intensity training would soon start to take its toll on your body. This would be like a weightlifter training with maximum weights every time they hit the gym.

So, make sure you also include easier workouts and rest days in your training schedule to allow for recovery and avoid overtraining. 

Here are a few different lactate threshold workouts to try. 

Please note: while we’ve used the term running for the following workouts, that’s simply for convenience. You can modify these workouts for cycling, swimming, rowing, and any other type of cardio.

Workout 1 – Tempo runs

Tempo runs are performed at your LT heart rate or pace. Because this type of training is quite intense, workouts tend to be relatively short and infrequent. For example, you might do a 20-30 minute tempo run once per week

Warm up with ten minutes of easy jogging, and then build up to your LT pace. Monitor your heart rate or effort and adjust your pace as necessary. Continue for the required duration and then cool down.

As you get fitter, you should be able to run faster or further at the same heart rate. Gradually increase the length of your tempo runs. Ten-percent increases are ideal, e.g., from 20 to 22 minutes.

Workout 2 – LT intervals 

Interval training involves alternating periods of high-intensity exercise with brief rests. They allow you to raise the average intensity of your workouts, exposing your body to more stress than it could handle if you trained continually. 

LT intervals involve training at or above your lactate threshold. The rests between efforts train your body to clear lactate more efficiently. Warm up before and cool down after interval training as you would for any workout. 

Good LT interval workouts include: 

•         6 x 3-minutes at LT pace
•         5 x 4-minutes at LT pace
•         4 x 6-minutes at LT pace
•         3 x 8-minutes at LT pace
•         2 x 10-minutes at LT pace
  
  

LT pace is usually around 80-90% effort so you can alternatively go off this.

Rests should be between 1:1 and 2:1, so if you ran for three minutes, you should rest 3-6 minutes before starting your next interval. Rest periods can be passive, i.e., sitting or standing still, or active, i.e., easy walking or light jogging.

Workout 3 – Fartlek running 

Fartlek is Swedish for speed play and a great way to start working on your lactate threshold. If you usually work out at a slow, steady pace, Fartlek will gently introduce you to training more intensely. 

To do a Fartlek workout, start running at an easy pace to warm up. Then, when you are ready, speed up your LT heart rate or pace. Maintain this level for a few minutes, and then slow down to recover.

Adjust the length of your efforts and recoveries based on how you feel rather than your watch. Emphasize the “play” part of this workout. Don’t feel that you have to be overly regimented when deciding how long or fast to run for each interval. Speed and duration should naturally increase as you get fitter. 

Continue for 30-45 minutes, and then end your workout with a cool down.

Improving Your Lactate Threshold – Closing Thoughts

If you want to run, row, cycle, or swim faster and longer, improving your lactate threshold will help. However, because lactate threshold training is quite demanding, you should only attempt it after establishing a foundation of basic aerobic fitness.

This is best achieved by training at a moderate intensity for 30-40 minutes 2-4 times per week. If you have yet to do this, you are not ready for LT training.

But if you’ve been working out consistently for a while and want to improve your performance, LT training will help. Introduce it gradually and remember to respect your body’s need for rest and recovery. Lactate training can take a lot out of you.