Just about every muscle building enthusiast has heard the term, “lactic acid burn.” The prevailing belief is that lactic acid, which also goes by the more accurate name of lactate, causes that burning sensation in the muscles as one approaches failure in a set with relatively high repetitions.
Lactic acid traditionally has gotten the bad rap of being this waste product of hard exercise that causes post-workout soreness, as well as that stinging burn during the workout.
Just What Is Lactic Acid?
As just mentioned, “lactate” is the more accurate terminology. The human metabolic process produces lactate, which acts like a hormone. A hormone is a chemical messenger that instructs things to happen in the body.
However, it is not this signaling molecule of lactate that’s responsible for the so-called lactic acid soreness. Instead, this chemical is simply associated with that burn; it is guilt by association!
Here Is What Happens During Hardcore Exercise:
When exercise is intense enough, aerobic capacity is maxed out. This causes hydrogen ions to accumulate in muscle cells. A hydrogen ion is a hydrogen atom that has lost its electron, making it positively charged.
So, the muscle cells have an accumulation of these ions. This increases the acidity of the muscle cells, causing them to “burn.” This increased acidity causes what many people refer to as the lactic acid burn.
Where Does Lactate Come In, Then?
Lactate scoops up these ions, thereby working against the shift in pH (increased acidity).
This is how lactate is associated with the muscle burn. This association, however, does not mean cause.
The formation of lactate helps fight the damage from the hydrogen ions. What happens to this formed lactate? One of several outcomes is possible:
- It remains in muscle cells to be reconverted to energy.
- It exits muscle cells to be utilized by other kinds of cells for fuel.
- It creates glucose (blood sugar) for the body to use for energy, a process called gluconeogenesis.
Lactate plays a strong role in energy metabolism. It’s important to understand a phenomenon called EPOC: excess post-exercise oxygen consumption, which occurs after intense cardio (such as high intensity interval training) as well as intense weight lifting.
In layman’s terms, EPOC is known as the after-burn of fat.
When lactate is formed (to combat those hydrogen ions that build up in muscle cells), heat is released. During intense exercise, the body’s aerobic system is not being used; the anaerobic (absence of oxygen) pathway instead is being used.
Thus, during anaerobic exercise, such as sprinting, heavy bench pressing or pull-ups to failure, the body is not relying upon oxygen like it does during a 5 mph jog. One can start out doing aerobic exercise, but then transition to anaerobic.
An example of transition would be high intensity interval training: going from a 3 mph walk to a brief 12 mph run and switching back and forth between these speeds; or going from warm-up deadlifts to the weight needed for a 6-rep max.
When the body switches over from aerobic to anaerobic energy metabolism, something happens. And that something is that pyruvate, a molecule, is converted to lactate.
This conversion process releases heat. Notice that it was previously mentioned that once lactate forms, one of three outcomes occurs, and the first possible outcome is that lactate can reconvert to energy.
However, before this stage takes place, lactate must be converted back to pyruvate.
Guess what: This conversion back to pyruvate also releases heat. There’s heat going on here, and this heat is very important for energy use; lactate improves one’s metabolic efficiency.
Lactate is considered to be virtually a hormone by researchers (such as Hashimoto et al) because it has cell signaling attributes.
As mentioned prior, when exercise is intense enough, it crosses the threshold into anaerobic metabolism—causing that accumulation of hydrogen ions, along with a buildup of pyruvate (which ultimately converts to lactate).
To recap, the “lactic acid muscle soreness” or burning is caused by the acidic changes that are caused by the ion buildup. Fatigue results. Lactate is formed. Lactate then heads down one or more of the three possible outcomes described earlier.
The signaling aspect of lactate is that it encourages the body to lay down metabolic processes in the name of better training performance. In this sense, lactate is called an adaptogen.
Two Main Signals Or Instructions Come Out Of Lactate’s Adaptogenic Properties:
1) Increase mitochondrial (cell energy) production, and
2) Increase production of human growth hormone and testosterone.
Hmmm, now we’re talking! Bodybuilders and other muscle building athletes love growth hormone and testosterone!
More mitochondria mean more energy and higher fatigue tolerance (and bigger muscles from the sarcoplasmic changes that more abundant mitochondria cause).
What we have here is a chemical chain reaction that all begins with intense exercise, and leads to an unleashing of growth promoting hormones.
The greater release of HGH and testosterone is preceded by the production of lactate; lactate is the precursor to these anabolic hormones.
The idea that lactate can actually be a hormone throws many people for a loop, but recent research has uncovered a receptor site for this signaling molecule. The receptor site is called GPR81, which means that, at a minimum, lactate behaves like a hormone.
Lactate’s Application To Building Muscle
Next time you experience “lactic acid muscle soreness,” welcome it with open arms, because you now know what it all means: lactate production—the startup of a chain reaction that culminates in a spike in anabolic hormones.
There are weight lifting techniques that spur this process, and, though not pretty as far as how they feel, keep in mind that the greater that grueling burn, the more HGH and testosterone will be released, meaning greater fat burning and muscle building.
Intensity Techniques For Driving Up Lactate:
These are absolute killers. The first set is done to failure or near failure, and immediately after is another set of the same exercise with lighter weight, to failure, and then again a third set of still the same exercise, even lighter, to failure.
Some routines are impractical for this, such as deadlifts, free barbell squats and leg presses due to the longer load changing times, but other routines work divinely for drop-sets such as any kind of rows, lat pull-downs, chest presses and shoulder presses.
2. Compound sets
A set is immediately followed by a different exercise that works the same muscle group, such as pull-ups quickly followed by barbell rows, or parallel bar dips promptly followed by narrow grip bench presses.
3. Partial repetitions
A fine example is bringing the leg press sled down deeply rather than half-way (like most people do), then pushing back up only three-fourths way rather than all the way. Each rep goes up only three-fourths way, from the lowest position possible.
Take five seconds to lower the weight, such as in a bench press or incline dumbbell press.
5. Stage reps
The lowering or release of the weight is not done in one fluid motion, but consists of pauses throughout.
An example would be a chin-up in which one lowers one-quarter way and holds; then lowers to half way and holds; lowers to three-fourths and holds, then comes to a dead hang before pulling up again.
Optimizing lactic acid for muscle building, or, more accurately put, optimizing lactate for muscle building, includes incorporating these intensity techniques into one’s muscle hypertrophy regimen.
However, don’t overdo it. Too many intensity sets in one session can become too exhausting. No more than half the exercises should utilize intensity techniques.