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Lactate Threshold 

This article will answer the following question in layman's terms, "What is lactate threshold and why is it important for athletes?"

In order to understand the concept of lactate threshold, it's important to understand how the body gets the energy it needs to fuel any physical activity. The body has two energy systems, the aerobic and anaerobic energy systems. Both of these systems use adenosine triphosphate (ATP) as their energy source.

The body takes the carbohydrates, proteins and fats from the food you ingest and converts it into ATP. Increasing the intensity and duration of a physical activity/exercise will increase the demand for ATP (fuel). Once your body is depleted of ATP, your athletic performance will diminish dramatically due to fatigue, low fuel supply and lactic acid buildup (more on this in a moment).

The aerobic and anaerobic energy systems produce ATP differently. The aerobic (low intensity exercise that lasts longer than two minutes) energy system uses oxygen to create ATP. In contrast, during high intensity exercise the body gets its ATP from the anaerobic (short bursts of high intensity lasting less than 20 seconds) system, which doesn't use oxygen to create ATP.

The anaerobic system has two components: the ATP-phosphocreatine (PC) and lactic acid system. During the first 5 to 20 seconds of high intensity exercise, the anaerobic system uses ATP-PC as the main source of energy, if the duration of intense activity is longer than 20 seconds, the anaerobic systems kicks in and provides energy via the lactic acid system. So in actuality, the body has three energy systems: the aerobic system; the ATP-PC system; and the lactic acid system.

Most sports utilize one or two of these systems the majority of the time, and use all three systems to some degree. For this reason, most athletes will benefit from training the anaerobic system, including the lactic acid system (via lactate threshold training).

When the lactic acid system is providing energy to the muscles, it creates a byproduct called lactic acid (lactate). The human body is constantly making and removing lactic acid at all activity levels, even if you're just pouring yourself a glass of milk or picking up a book. However, as the exercise intensity increases so does the production of lactic acid. During light or moderate activity the body is able to absorb the lactic acid faster than the body produces it; thereby keeping the lactic acid levels in the blood low.

When the body produces more lactic acid than it can get rid of, you will experience a burning sensation in your muscles and you will be forced to stop or decrease the intensity level substantially. This is your lactate threshold. In other words, your lactate threshold is the point where the body is unable to remove the lactic acid at the same rate it produces it. Your lactate threshold is a key determinant of your endurance performance because it determine how long and at what intensity you can perform at.

Stated differently...

"As an athlete, the higher your lactate threshold, the higher
your average speed and power output will be..."

Athletes in the following sports will benefit the most from lactate threshold training:
  • basketball
  • cycling
  • distance running (5k runners, 10k runners, marathon runners etc.)
  • marathon
  • mixed martial arts (MMA)
  • rowing
  • soccer
  • swimming
  • triathlon (Ironman etc.)
  • wrestling
  • x-country skiing
Athletes should be aware that the lactic acid system only uses carbohydrates to produce ATP. So it's important to eat a carbohydrate rich meal before competition. In case you're wondering, the aerobic energy system uses carbohydrates, protein and fat to produce ATP.

How Calculate Your Lactate Threshold

The most accurate way to determine your lactate threshold is through a lactate acid test, which is normally done through your health care provider; however, I'm going to show you how to estimate your lactate threshold with a heart rate monitor or a power meter.

1. Warm-up for 10 minutes.
2. Cycle or run on surface at a highest intensity that you can maintain for 30 minutes. Make sure the surface has no hills or declines.
3. With heart rate monitor: If you have a heart rate monitor, record the last 20 minutes and your average heart rate over this period is you lactate threshold heart rate (LTHR). 
3. With power meter: Record your power for the last 20 minutes. The average power for the 20 minutes is your lactate threshold in watts.

You will want to perform this test once every month or two to track the progress of your training. When you do the retest, make sure you use the same bike, road, course, and conditions to ensure the most accurate reading.

One final note, you may have heard of the term anaerobic threshold, anaerobic and lactate threshold are synonymous.

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