Inside every cell, including muscle cells, are “energy machines” or “engines” called mitochondria (singular, mitochondrion). Mitochondria are important because they are primary players in oxygen consumption.
It’s easy to see from this that the more mitochondria that a person has (i.e., the higher the mitochondrial density), the more fuel from incoming food that a person has available to burn—and hence, the better the performance, whether in sport or in the weight room.
Greater mitochondrial density means, quite simply, greater capacity to use oxygen. When one knows this fact of the human body, the inevitable plan is then to increase mitochondrial density.
How Can Mitochondrial Density Be Increased?
Higher exercise levels are the plan of action. The body is forced to generate more of these energy engines to accommodate the increased demand of working out. When exercise (which includes cardio) is increased either in duration or intensity, more mitochondria are produced by the cells.
There is a relationship between a person’s physical fitness and the degree of mitochondrial production. The production will be limited if the physical activity is limited.
For instance, a sedentary person who never exercises and then decides to walk steady state 30 minutes every day, will end up with more mitochondria.
It won’t be long before the body adapts to the limited challenge of a 30 minute steady state walk, and mitochondrial growth will stabilize and no longer increase.
To produce even more of these cellular structures, one must up the ante, either by walking for a longer period of time, or by wedging in some brief sprints, jogs or hill courses throughout the walking session.
It’s clear that going for longer sessions will eventually become impractical. Mitochondrial density can indeed be increased during that same 30 minutes by elevating the intensity.
As just mentioned, the trainee can accomplish this by inserting sprint intervals into that same 30 minute walk. This is called high intensity interval training (HIIT), and a savvy muscle building enthusiast realizes the power of HIIT for its fat burning effects.
Intense Exercise Turns Up The Heat Of Mitochondrial Production
This process involves the signaling molecules of nitric oxide and lactate. These compounds enhance oxygen production by increasing the blood flow to exercising muscles. The result is increased mitochondria.
Nitric oxide creates the action of opening up the athlete’s arteries for increased blood flow to working muscles, which keeps oxygen levels in muscles up to par, reducing fatigue.
Where Does Nitric Oxide Come From?
It comes from the cells lining blood vessels, but also from muscle tissue. Again, this signaling molecule increases the blood flow to the muscles that are being exercised. The nitric oxide in muscle tissue also increases mitochondrial synthesis.
This is how the body adapts to increased exercise levels. In other words, driving up the intensity of exercise increases the production of nitric oxide. Intensity, not duration, is key.
In fact, there are a number of studies (like the one reported in Circulation, a journal of the American Heart Association) that demonstrate the superiority of highly intense exercise (like HIIT) over moderate or more steady state exercise for elevating nitric oxide.
The production of nitric oxide in muscle is a crucial fixture in switching on the signals that increase mitochondrial density.
What About Lactic Acid?
Hard exercise increases lactic acid (a.k.a. lactate) production. This signaling molecule brings up mitochondrial levels. Lactate production is a critical factor in the signaling for greater mitochondria.
How Does This All Tie In To Building Muscle And Exercise Performance?
Quite simply, the more oxygen that’s in the athlete’s bloodstream, the harder he or she can work out – be it running or lifting heavy weights. Building muscle demands brief bouts of high exertion.
Lots of oxygen means better performance, which leads to more hypertrophy and fat loss. A lot of oxygen comes from robust mitochondrial density.
When it comes to workout performance, there are three things to take note of. The first is VO2 max. This relates to the oxygen amount that the athlete can consume and make use of.
The VO2 max is a measurement of how much oxygen gets delivered from the athlete’s lungs to the circulating blood, and from the blood to the muscle cell, and then from the cell to the mitochondria, which are located in the cell’s nucleus (center).
The second is lactate threshold. This refers to the point in which the production of lactate is greater than the body’s ability to clear this signaling molecule out. (Remember, lactic acid is a byproduct of exercise.)
This threshold is the point of transition from aerobic-based exercise (e.g., walking lunges with light dumbbells) to anaerobic exercise (e.g., walking lunges with very heavy dumbbells).
Anaerobic exercise (another example: wind sprints) causes byproducts that cause fatigue buildup. The greater an athlete’s mitochondrial density (number of these structures), the higher the lactate threshold.
In plain English, a person who conks out with a brief 6 mph jog has a low lactate threshold (poor mitochondrial density). One who needs to sprint at 14 mph to reach exhaustion within 15 seconds has a much greater mitochondrial density, or higher lactate threshold.
The third factor is called exercise economy, which relates to movement efficiency. Simply put, the stronger that one’s body is, the more efficiently it can move. Efficient movement requires less oxygen!
This is why building muscle carries over to endurance activities; the weight trained individual, with a stronger body, will be able to run or cycle more efficiently.
How Does Nitric Oxide Benefit The Muscle Building Enthusiast?
- Intense exercise, as explained prior, drives up the amount of nitric oxide. More nitric oxide means a higher concentration of IGF-1: insulin-like growth factor. This hormone promotes hypertrophy.
- Because this signaling molecule encourages muscles to relax, more oxygen and nutrients get into exercising muscles, as well as post-workout, fatigued muscles.
Better recovery means that the next workout can be full-blast.
- Nitric oxide fights against the burning fatigue (from lactic acid) that accumulates during higher rep routines—that agonizing “burn” that forces one to quit the set even though he or she is still strong enough to complete several more reps.
It’s A Chain Reaction That Is Of Benefit To Every Person Wanting To Build Muscle:
1. Do intense exercise, including cardio interval training (HIIT), to increase mitochondrial density.
2. This will lead to greater production of nitric oxide.
3. More nitric oxide will improve blood flow to working muscles as well as to muscles post-workout.
4. More nitric oxide will mean more IGF-1 for muscle growth.
5. More nitric oxide will result in improved performance, better toleration of high-rep routines, and faster recovery, which will promote more hypertrophy.
Oxygen consumption is something that every muscle building athlete needs to consider when training. The ticket to greater oxygen consumption is a training regime that promotes the density of a muscle cell’s storehouse of energy: the mitochondria.