The Curious Case of Lactate

 

Lactate is produced in the cells of the body on a constant basis.  Quick, blink!  You just produced lactate in the muscles of your eyelid. 

Because these sorts of activities produce very small amounts of lactate, the body disposes of it quickly and efficiently by transporting it to the liver where it is filtered from the blood and converted to usable carbohydrate fuel.  Lactate is actually what is left behind when a glucose molecule in the cytoplasm of the muscle cell cleaves during anaerobic respiration, and a hydrogen ion separates off. 

The loose hydrogen ion actually does the damage to the cell and ultimately causes anaerobic workout fatigue.  The huge lactate molecule is benign, but it is what scientists’ measure when experimenting with lactic acid production because there is a direct ratio to the quantity of lactate produced to hydrogen ions on the loose. 

When a great quantity of lactate is detected, then there is a great quantity of hydrogen ions also present.  This condition is termed acidosis and it is what causes 400 meter runners to look so awkward and fatigued as they finish their races.

All humans have an ability to tolerate some hydrogen ion presence.  The loose hydrogen ions have a positive electrical charge, and are called acidic because of this charge.  Humans also have a certain quantity of loose negative ions present.  The negative ions buffer the positive ions of the acid and neutrality returns to the system.  The negative ions may be stores of sodium bicarbonate found between cells, hemoglobin in the blood, and other assorted chemicals present. 

Compared to many other animals humans are not fast runners and have little ability to hold top speed.  Physiologists call this a low lactate response (LLR).  However, through directed anaerobic training, humans can improve this LLR. 

Runners in combined zone races like the distance races between 800 meters and 10000 meters spend a lot of effort developing their aerobic energy system, but they also spend time developing their anaerobic energy system as well.  The development of the anaerobic energy system fitness is chiefly directed toward increasing the amount of stored negative ions present, in order to more effectively buffer greater amounts of hydrogen positive ions produced.  The main training target is to increase the amount of sodium bicarbonate present through adaptation to stimulus.

Despite the efforts of many, no source of supplemental sodium bicarbonate that the body will absorb has been found.  The increased stores of this ion found in distance runners must be earned. 

Physiologists have discovered that it takes about 9-11 weeks of sea-level training to fully develop the sodium bicarbonate stores through directed and consistent anaerobic training.  Curiously, physiologists have also found that sodium bicarbonate does not store well in the body at altitudes above 5000 feet.  This may explain why VO_{2 max} decreases in an athlete above this altitude.  VO_{2 max} is a measure of aerobic power, and defined in most protocols as the effort to run two miles to exhaustion. This task is known to be an exercise completed at a mixture of 87% aerobically supplied energy and 13% anaerobically supplied energy.  The decrease in aerobic power seen at altitude probably comes from the compromised anaerobic contribution.

Related: The Balke VO2 Max Test

Training studies done both at altitude and sea-level in the 1990’s on distance runners by scientists James Stray-Gunderson Ph D and Benjamin Levine Ph D indicated that the most effective training protocol for athletes in the 800-100000 meter range was to “live high and train low”.  By living 20 hours per day at 7000 feet (Park City, Utah), the runners adapted to normal life at altitude.  They increased their blood plasma volume, hematocrit ratio, erythrocyte, myoglobin, and hemoglobin mass.  Through angiogenesis they increased their capillary beds and enlarged the left ventricle of their heart.  All of these adaptations made them better distance runners on the aerobic energy side.  However, they did not increase their sodium bicarbonate stores which were not stimulated by the effects of altitude.

For anaerobic development the athletes trained some days on a track at low altitude (Salt Lake City, Utah) which was convenient to where they lived.  By training anaerobically at an altitude of 3800 feet they did increase their sodium bicarbonate stores.  They became faster and did not loose VO_{2 max}.  This live high, train low, protocol has become the accepted training regime for many world-class combined zone distance runners.

There is no substitute for speed in track and field events or any other sport.  Weight room activities increase strength and thus help increase speed to a point, but strength training does increase sodium bicarbonate stores.  Performing long runs improve the aerobic fitness of the distance runner, but does not improve anaerobic buffering ability. 

Scientists’ measure lactate produced in a unit called millimole/kg of body mass.  Your lactate millimole value right now as you read this is about 0.5-1.0 millimole/kg.  To reach the threshold where more lactate (and hydrogen) is produced then can be removed you must reach about 2.0 millimole/kg.  Coaches and physiologists speak of this as the lactate threshold.  Training often right at this 2.0 millimole/kg threshold increases sodium bicarbonate stores slightly. 

Resource: Complete Cross Country Training by Scott Christensen

Training often way over the threshold is a stronger stimulus and will increase stores to a greater extent.  The role of the coach is to sequence enough workouts, from tempo runs to interval sessions, during the season to fully develop an athlete’s buffering capability based on the demands of the distance event.