You are in a middle of short, intense climb up the mountain or performing intervals runs in the park. Your legs are stiff, and your muscles are getting tired rapidly. It prevents you from performing. Why is this happening? What is the lactate threshold, how it relates to your fitness level, and how you should train to outperform?
Let us understand better the metabolism process for energy creation and what happens during intense activity in which the lactate takes an active part.
ATP, Adenosine Triphosphate, is the energy transfer molecule, which during the chemical process inside the cells, produces energy release- heat and work.
Cells breathing can roughly be divided into three processes:
Instant use of available energy, ATP, during the first intense seconds of the activity. Anaerobic breathing using available ATP/Cp (Creatine Phosphate), anaerobic respiration using glucose and lactate to produce energy and, Aerobic respiration, which uses oxygen and glucose to produce energy.
During these processes, we also produce Carbone Dioxide (which the body needs to clear out) and water
Leftovers of glucose, which are beyond the level the liver can hold, the body will turn into fat for long-term energy storage.
When cells are using glucose, it can come either from available glucose in the muscles and liver or can come from fat tissues, and the body can liquidate when carbohydrates are scarce.
During exercise, the muscle cells respire more than they do at rest. It means more oxygen and glucose to deliver and more quickly, and there is more waste of carbon dioxide to remove.
Click here for more details on the energy pathways.
ATP is the substance the body uses as the energy molecule. During aerobic respiration, the body produces 38 ATP with a single molecule of glucose. During anaerobic respiration, the body produces only 2 ATP. Aerobic respiration is more efficient, but, the process is too slow, the body must use other sources to produce energy and turns to anaerobic energy processing in which lactate is used.
Once the body has depleted the readily available energy stores (ATP and Creatine Phosphate), the body must break down carbohydrates to produce more ATP. This process uses either glycogen (which is stored in the muscle cells) or glucose (which is found in the blood) to convert ADP back into ATP; the waste product is lactic acid
This lactic acid eventually builds more quickly than it can be flushed out of the muscle to the point of the anaerobic threshold, otherwise known as muscular fatigue. At this point, the body must either stop or slow down until the lactic acid is removed. Lactic acid is converted to a less toxic form, called lactate, which is used either as an energy substrate or to produce more glucose (a process called gluconeogenesis). Getting rid of lactic acid is not as important as it is how efficiently the body can use it.
What we also need to understand is that the lactic acid is transferred back to an energy source: Lactic acid is cleared from the muscle, fed into the bloodstream, taken to the liver, and there, made into glucose and glycogen.
So unlike the myth, lactate is not our enemy but a vital energy source.
When our muscles burn during the intensified activity, this is not due to lactate, a substance that helps muscle contractions.
Being fitter means you can keep aerobic breathing longer before moving to lactate processing.
This often called lactate threshold, and the fitter you are, the more ATP you can produce in aerobic respiration, so you will have more available energy rather than a less efficient process, which results in tiredness.
So, as lactate is the standard endpoint of glucose breakdown during anaerobic cell respiration, it can be used by the cells as an instant source of energy or, it exists the cells and transported to the liver and can be converted back to glucose.
With a persistent oxygen debt, lactate levels rise, and lactic acidosis ensues and rises.
Some of the major changes measured as a result of anaerobic exercise include increased size and number of fast-twitch muscle fibers. In addition, anaerobic work results in increased tolerance to higher levels of blood lactate, an increase in enzymes involved in the anaerobic phase of glucose breakdown (glycolysis), and an increase in muscle resting levels of ATP, CP, creatine, and glycogen content. Finally, anaerobic changes include an increase in growth hormone and testosterone levels after short bouts (45–75 min) of high-intensity weight training.
Being more fit means more efficient cell metabolism to produce the required energy during activities. It means we can perform better, train harder, climb faster, lift more weights, and having more intense exercises, both aerobic and anaerobic.
The goal of a good strength and conditioning program is to sustain more speed and power before hitting the lactate threshold. It means more time using efficient respiration, producing more ATP, providing the required energy to the cells.
If we would like to improve our fitness and, developing both aerobic and anaerobic capacities, we need to train appropriately. We need training that stimulates this equilibrium of the lactate threshold — eventually leading to a higher threshold and more duration of efficient cell respiration.
It is backup up with the data from researchers that high-intensity interval training can be an efficient way to improve our fitness levels.
Prof. Izumi Tabata tested in 1996 Hgh-Intensity Interval training in the form of 20 seconds of maximal activity, followed by 10 seconds of rest for eight rounds. This was tested compared to a low-intensity workout routine.
Research showed that athletes that did the Tabata routine increased both their aerobic and anaerobic capacity while lower-intensity common routines only improved their aerobic capacity.
Depends on your activity, you may choose different routines to improve those factors.
Climbers, for example, should practice specifically targeted routines to improve the capacity and strength of the more relevant muscles for climbing.
Martial arts also often require this higher capacity while practicing martial arts are forms of intensity intervals in which one needs to use both rapid strength and sprinting in intervals manners.
This goes the same if you would like to improve your basketball playing by having more explosive power to leap jump or sprinting rapidly. The same goes when bouldering and building routines to improve your capabilities or other activities in which you combine strength and endurance.
You can read more about energy processing and the relation to food glycemic indexes for fitness benefits.
[…] You can read further about lactate in our lactate explained article. […]
