Testing protocols to determine lactate threshold are sport-specific. Many consider the running speed at lactate threshold (RSLT) to be the best indicator of running fitness and the most reliable barometer of endurance performance.
In cycling, step-tests (where power is increased at regular intervals until you are exhausted) are the gold standard for measuring physiological performance markers, such as lactate threshold.
Upon completing the test and finding a personal lactate threshold, one can begin incorporating lactate threshold training to target specific adaptations for the body to make.
There are a few different ways to test for a personal lactate threshold, and factors to consider when doing so. It’s important to remember everyone is different, and lactate threshold changes in response to training (or sadly, de-training).
Lab Testing: Accurate But Expensive
The most concrete way to determine lactate threshold is to take a series of blood samples as exercise is conducted at increasing intensities. This type of lactate testing occurs at an exercise physiology laboratory, and tends to be expensive (but worth it).
In a lactate threshold test, athletes exercise on a treadmill or stationary bike while increasing intensity every few minutes until exhaustion. A blood sample is taken during the each stage of the test–similar to testing for ketones, through the fingertip or earlobe–illustrating blood lactate readings at various running speeds or cycling power outputs. Results are then plotted on a curve to show the speed or power at which the lactate threshold occurs.
However, lactate threshold changes as more training is done to build your aerobic base. So in order to maintain an updated understanding of your lactate threshold, you’d have to visit the lab again after a block of training.
During her time on the Great Britian Rowing Team, HVMN Research lead, Dr Brianna Stubbs, did lactate threshold testing every 2-3 months. She recounts the collective effort to find lactate threshold.
"The gym even got gory on step-test days, with athletes dripping blood from the testing holes in their earlobes."Dr. Brianna Stubbs
"Seeing results change over time was interesting," she said. "I recorded my highest power at lactate threshold toward the end of the winter training block, which made sense because that’s when we did most of our endurance work."
Do-it-Yourself Field Test: You Have a Few Options
Many endurance athletes choose to estimate their lactate threshold by measuring heart rate and/or VO2 max at different training zones (there’s even a portable lactate blood analyzer some use to further cement results).
There are several different methods to estimate running speed at lactate threshold:
VDOT (or VO2 max) Chart
A VDOT chart is an adjusted VO2 max chart (created by esteemed running coach Jack Daniels) that uses some of your most recent run times (at max effort) to identify training pace that will maintain your lactate threshold. There are two corresponding chats that work together to illustrate max effort and training paces for different distances (we've simplified it above)
For example, running at a 7:49 mile pace at max effort corresponds to a VDOT number of 36. That VDOT number illustrates the pace at which training should be done to maintain lactate recycling: 8:55. For a more in-depth analysis of interval training and different distances, refer to these charts here
Using a heart rate monitor set to a five second recording interval
Begin running and increase speed every 200 meters until exhaustion. The goal isn’t to maintain a steady state of exercise, instead increasing incrementally to test yourself
Plot heart rate against speed; the deflection point in the graph (where your heart rate goes up much more than your speed) roughly corresponds to speed at lactate threshold
Time-Trial Method / 30-Minute Test
Research has shown that doing a 30 minute flat out time trial is one of the most accurate ways to find your lactate threshold without using fancy equipment3
Start by warming up
Then, on a track or treadmill, run for 30 minutes at the fastest sustainable pace. 10 minutes into the run, obtain and note your heart rate. Then, after the final 20 minutes of the test, obtain and note your heart rate again
Add your heart rate at the 10-minute mark to heart rate at the 30-minute mark–that's your lactate threshold heart rate. And your average pace for the entire 30-minute test (assuming it was steady) is your lactate threshold pace
Both elite athletes and weekend warriors can benefit from understanding personal lactate threshold to maximize results. However, lactate threshold is impacted by training and changes over time. So keeping regular on these types of tests will indicate an improving lactate threshold through focused training.
Optimizing Lactate Metabolism
Lactic acid gets blamed for muscle soreness, but the production of lactate is an important metabolic process. The idea that lactate is pure waste and leads to fatigue is somewhat outdated. Nevertheless, a higher speed or power at lactate threshold is still one of the key goals of aerobic training.1
Different strategies can help minimize lactate buildup during exercise.
Warming Up: As Important as Cooling Down
Warming up is important to reducing risk for injury and minimizing potential lactate buildup. During a warm-up, heart rate increases, and blood vessels dilate, meaning there is more blood flow and more oxygen reaching your muscles.
When exercise intensity picks up the pace, there’s less mismatch between oxygen needs of the muscles and blood. Therefore, you don’t need to do as much anaerobic respiration, and you don’t build lactate early in the run.
Equally, cooling down and stretching immediately after a workout is especially important. Gentle exercise (slow jogging or spinning on a bike) or using a foam roller can help clear lactic acid buildup from the muscle by stimulating blood flow and encouraging lymphatic drainage.
Nutrition and Supplements: Replenishment is Key
The key to dealing with high lactate production is dealing with the acid associated with it (that pesky little proton). Two “buffer supplements,” sodium bicarbonate and beta-alanine, work by mopping up that proton. This means lactate levels can go higher than before without triggering fatigue because the proton is taken care of.
Beta-alanine works inside the muscles to clean up protons before they affect muscle contraction. Compounding effects of beta-alanine powder (~5g per day) happen after several weeks, but studies show around a 2-3% performance boost.4
Sodium bicarbonate is better for short-term boosts in proton buffering. Bicarbonate is the main buffer usually binding protons to stop blood from becoming too acidic. About an hour before exercise, taking bicarb powder dissolved in water, at 0.3kg per body weight, has shown to improve performance.5 Be weary of stomach aches when first introducing bicarb. But there are bicarbonate gels that provide the same buffing effect without the side-effects.6
Lactate can only be produced by breaking down carbs. Sustaining an exercise intensity that is producing lactate means the depletion carbohydrate stores (glycogen). When the glycogen gas tank reads empty, we hit a wall.
Exogenous ketones can lower lactate production. By drinking pre-workout exogenous ketones, like HVMN Ketone, your body can use the ketones for energy instead of carbohydrates–glycolysis decreases and therefore, so does lactate production.