Medical

Lactate Threshold: What Is It And Why Should You Care About It

Lactate threshold is a significant physiological variable used in the distance running world. Most athletes and fitness coaches use it to monitor workout plans and to enhance sports performance and intensity. Lactate threshold is a measure of endurance performance.

By Suresh Srinivasan

11 Jul 2022

Ever tried sprinting as hard as you can? Or squatting until overwhelming pain in the legs made it impossible to do so? Most athletes and fitness trainers workout rigorously to achieve endurance and perform at their best ability by overcoming their lactate threshold. Surpassing the lactate threshold, the quantity of lactic acid in your muscles rises exponentially and results in muscle soreness and fatigue. Lactate threshold is a term used to describe a constant state where a person can perform high intensity interval training and aerobic exercises without wearing out.

Most athletes and fitness trainers workout rigorously to achieve endurance and perform at their best ability by overcoming their lactate threshold. They succeed in their training by determining how to workout and how to maintain their stamina beyond this limit. So if you are an athlete or a distance runner, you would have experienced lactate threshold workouts or anaerobic threshold as part of your training cycle.

To understand lactate threshold better, we approached New Delhi-based marathon trainer and athlete Suresh Srinivasan. He explains, Lactate threshold or anaerobic threshold or ventilatory anaerobic threshold this occurs at 55-65% of VO2 max in healthy untrained people or 80-85% of VO2 max in trained athletes “high intensity workouts require a huge amount of energy quickly for muscles to function better. When exercising at a high intensity, the body breaks down glucose (sugar) to generate ATP (cellular energy) in the presence of oxygen with energy production, lactic acid can be formed during carbohydrate metabolism and if the energy requirements are high lactic acid can get accumulated in the cell, in the absence of oxygen (anaerobic). The end product from anaerobic metabolism is pyruvic acid or pyruvate which can be directed into an aerobic energy system where it gets oxidised to produce energy.

When lactic acid starts accumulating in the working muscles they spill out into the capillary and venous blood and this process is referred to as the onset of blood lactate accumulation (OBLA). The important point to understand here the rate at which the lactate is produced if it's cleared then there is no problem, there will be a point in the exercise/running stage where the lactate production will be higher than the removal rate, at this stage there will be a rapid build-up of lactate in the muscle. The hydrogen ions associated with lactate become more concentrated, they can slow down the muscle contraction and could lead to cessation of the exercise/run if the intensity is not reduced.

What’s Lactate Threshold

The lactate threshold is the highest exercise intensity the body can sustain without exhaustion. While at rest, your body produces and removes lactate in the blood at the same time. Lactate is produced faster than the body can absorb during medium high-intensity exercise. In other words, the lactate build-up reaches a verge where it can't be absorbed further and accumulates. This point is the lactate threshold.

The higher the lactate threshold, the longer an athlete can continue at a high-intensity effort. Top and well trained athletes are competent and have lower blood lactate levels. They shed it in higher portions in the lactate-producing muscle, which takes seconds or milliseconds. This is very beneficial for them as it allows muscles to contract and lactate quickly “recycle” for extra fuel generation(ATP).

Mr. Srinivasan says, the benefit of incorporating a Lactate threshold workout is you can sustain and hold a pace below your threshold for a longer time. Many coaches recommend including short tempo and medium tempo workouts at an appropriate phase of their training cycle to build - speed, stamina and endurance to sustain the rigour of meeting your race goals. Something that one can comfortably last and hold. Duration of these runs can be 20 mins to 40 minutes.

Lactate Threshold Values

Muscles produce lactate even at rest, usually about 1-2 mmol/L. Here are the estimated lactate threshold values for an average person and endurance athlete.

Average person: 60% of VO2 max
Recreational athlete: 65% to 80% of VO2 max
Elite endurance athlete: 85% to 95% of VO2 max2

How to Measure Lactate Threshold

Lactate analysing can provide a lot of information on muscles’ metabolic stress and performance in endurance athletes. Sportspeople usually utilise their lactate threshold to determine how to train and what speed they have to retain during strength exercises.

Lactate threshold tests are similar to VO2 max testing, using either a treadmill or a stagnant bicycle. Blood is collected with a finger stick after four to five minutes of intense workout to analyse blood lactate concentration, heart rate, power output, and VO2 max. The test continues until lactate concentration reaches the highest point. The power is measured in watts/kg.

How To Improve Lactate Threshold

Heavy workout demands muscles to produce more energy which means utilisation of glucose in higher amounts resulting in more lactate production. But, the high accumulation of lactate in the blood can hinder velocity, and performance and a decrease in muscle contraction ability. The good news is that your body is adaptable and with strategic training one can become efficient in using anaerobic respiration, thus improving lactate threshold. Finally, nothing compares by keeping it simple and staying consistent with your training routine.

How To Build Lactate Threshold:

Running extra miles

Running further than usual is one of the most effective ways to improve lactate threshold. The idea of this type of training is to get your body used to utilising more oxygen, so that when hitting longer races, your body will cooperate going faster.

Interval training

Interval running allows you to cover a specified stretch while running at your highest velocity, exceeding your lactate threshold before taking a break. During this process, your body increases its efficiency by using oxygen and prepares muscles to remove lactic acid faster.

Fartlek running

Including the Fartlek running program in your training can benefit in boosting lactate threshold greatly as it is a mix of high-speed anaerobic running above your lactate threshold. Fartlek running is derived from the Swedish word for ‘speed play’, which is similar to interval running. This workout involves unanticipated deviations in speed and intensity, alternating between running and slower ‘recovery’ jogging.

Tempo running

Tempo running is another popular workout to improve lactate threshold. In this method, you sprint at a pace just below your lactate threshold, where recovery breaks can be painful. It is the right time to notice body tempo or rhythm and follow it for extended periods. When feeling pain, slow down and let the lactate clear.

How to Estimate Lactate Threshold

There are a few ways that you can determine your lactate threshold yourself:

Speed calculator (Invasive)

Use one of the commercially available, portable, pretty accurate lactate analysers. For this, you ought to be a little tech-savvy with blood-sampling handling procedures. Sting your finger constantly to perform the threshold test and the results will be reflected in the graph. The graph shows the lactate level in the body and it helps you to decide where you want your lactate threshold to be and manage it accordingly.

30-minute test (Non-invasive)

According to a 2018 research article issued in Plos One, anaerobic threshold can be determined during an intense workout, cycling or running without stopping via heart rate.

You can do a 30-minute time trial using a level road or a treadmill set at 1% incline and a heart rate monitor. Warm-up your body for 10 minutes, like walking or an easy jog. After the warm-up, start sprinting at the most rapid speed you can carry on for 30 minutes straight. While doing this, ensure to be at a constant pace over the 30 minutes: make sure you don’t start too fast and taper off as you get tired.

Estimate 10 minutes into your run. Continue your run and estimate your heart rate at 30 minutes and divide by 2 to find the average. This is an estimate of your lactate threshold heart rate. Some Models of Garmin such as Garmin FR 945 can give your Lactate threshold guided test that you can run, you will need a Chest based heart rate monitor it is a 20-30 min test.

Heart rate training zones in percentages:

Recovery zone or aerobic training: 50-70% MHR
Tempo and threshold runs: 71-85% MHR
Intervals: >85% MHR

Other Measures To Improve Fitness And Intensity

Several athletes and trainers create training plans to increase intensity of lactate thresholds through various means.

VO2 max

A 2022 review article in Translation Sports Medicine says that VO2 max is the maximum consumption of oxygen your body can endure and use while exercising. VO2 max can be measured in a lab and calculating the amount of inhaled and exhaled oxygen. Higher the VO2 max the better cardiovascular ability than someone with a lower VO2 max. You can improve your VO2 max by becoming more prepared through training.

Heart rate

Your maximum heart rate (MHR) is the fastest rate your heart beats in a minute. Knowing your MHR helps to track training and determine what heart rate level you need to achieve. You can improve lactate threshold if you know your resting heart rate (RHT), with the recognized Karvonen formula. This formula is helpful to estimate your maximum heart rate and age, reveals Human Performance Resources in 2016.

THR = Target heart rate
MHR = Max heart rate
RHR = resting heart rate

THR = [ (MHR – RHR) x % intensity] + RHR

MHR = 220 – Age

Rate of perceived exertion

According to a 2022 study published in the International Journal of Sports Physiology and Performance, the rating of perceived exertion (RPE)is a subjective way for an individual to measure the difficulty level of his or her workout by noticing rapid breathing, heart rate, sweat, and muscle fatigue. The Rate of Perceived Exertion Scale (RPE) runs from 0 at the lowest amount of effort to 10 and the maximum level of exertion.

The article has been verified by New Delhi-based marathon trainer and athlete Suresh Srinivasan. Find related articles from Coach Suresh Srinivasan :

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