How Important is Lactate Threshold? by John Josephs, MS, CSCS
Filed under: Exercise Science
Lactate Threshold
What can you do differently this season to actually improve your performance? Allow me to explain to you the most important physiological fitness variable that you can train and improve, your Lactate Threshold (LT).
Scientists have reported that the lactate threshold is the most consistent predictor of performance in endurance events. Studies have repeatedly found high correlations between performance in endurance events such as running, cycling, and race-walking and the maximal steady-state workload at the lactate threshold (McKardle, Katch, & Katch 1996).
Lactate Threshold:
· is the point in exercise intensity where your cardiovascular system can no longer deliver adequate oxygen to the working muscles and the body no longer has a balanced exchange of oxygen intake and the removal of Lactic Acid (LA), the waste byproducts produced by the anaerobic energy system.
· is the level of physical performance at which the muscles produce more LA than can be removed by the liver and muscle enzyme (buffering) systems. However, it's not the LA that is the problem; it's the excess amount of LA and the problems it subsequently creates.
When LA starts to accumulate, one of the primary detrimental changes that occur is that it raises the blood pH levels creating a very acidic environment for normal function. The greater your performance is above your LT, the faster LA will accumulate. This accumulation eventually leads to fatigue and you will either have to slow your pace and/or stop. There is a very fine line or physiological tipping point where this occurs. If you train with a heart rate (HR) monitor or a power meter (PM) and have been previously tested, you should be aware of your LT limit. If not, your LT can be identified more subjectively when your breathing begins to get more labored.
"You reap what you sow."
What can you do to prevent this? Well the simple answer to this is to slow down and return to your aerobic energy zone. But to get the most from your training, you need to train specifically to improve your LT. By knowing your LTHR or LT power, you can do interval training to increase the level of your LT and make those numbers higher, thereby, increasing you aerobic energy zone as well. This is also referred to as your Aerobic Threshold (AT).
Another benefit of having a higher LT and AT is you'll be able to oxidize or burn more fat as fuel and be able to preserve you limited reserve of stored muscle glycogen. This will make you more efficient in burning fuel for training and exercise. This becomes more critical as the distance of your training and racing increases.
Be specific, train your LT, and reap the benefits!
At rest and under steady-state exercise conditions, there is a balance between blood lactate production and blood lactate removal (Brooks 2000).
LT refers to the intensity of exercise at which there is an increase in blood lactate as shown by the upswing slope to the left and the green markers indicating higher blood lactate levels..