Energy is life. Our bodies are an intricately complex system built for the essential task of generating and dispersing energy. Believe it or not, you are in control of how much energy your system creates. 

Regular exercise prompts your body to increase activity to match your needs. The inverse is also true. A sedentary lifestyle inhibits function to conserve its most vital resources.

But to truly understand energy, you have to look at the many cellular processes that are involved. 

You need to look under the microscope to play witness. Every day, your body uses these seven mechanisms to drive you forward.

1. Mitochondria

You may remember these being referred to as the “powerhouses of the cell.”

Mitochondria have a role in nearly every mechanism and process within the human body. Every known function requires the energy generated within these microscopic “engines.”

Organs or tissues with high energy demand, like the heart and liver, often have a higher number of mitochondria per cell. According to the British Society for Cell Biology, mitochondria occupy roughly 40% of all cytoplasmic space within heart muscle cells. Likewise, each liver cell that helps your body filter out toxins and waste can play host to 1000-2000 mitochondria.

Without these organelles, we couldn’t move, breathe, eat, or even think. In short, your mitochondria make action possible. 

2. The matrix

Each mitochondrion consists of two internal compartments: the mitochondrial matrix and an intermembrane space. A review published in Biochemistry states that the mitochondrial matrix is a gel-like material where cells hold and release stored energy.

The matrix is the primary working component of a mitochondrion. It functions as a storage space for the many enzymes, coenzymes, and proteins your body needs to generate energy. As mentioned above, it is also responsible for storing energy itself.

The matrix also helps mitochondria process their own genome to facilitate the replication, repair, and recombination of “bacterial and nuclear DNA.” 

What does this mean?

Replication: During replication, DNA creates two identical copies of the original strand of DNA.

Repair: After replication, DNA works with enzymes to fix any resulting damage or errors in the genetic code. Some changes in replication, known as mutations, cannot be repaired and may be passed onto future generations.

Recombination: After DNA replicates, two independent strands of DNA are joined in a process called recombination. 

The multiplication of mitochondrial DNA ultimately determines how many mitochondria live within each cell and how much energy will be expended for essential tasks. Energetically expensive tissue like muscle is known for having a high number of mitochondria per cell.

3. Fission

Fission, or the division of mitochondria, is one of the many ways your body maintains the ability to create energy. In short, it helps a cell generate the appropriate number of mitochondria for its task within the body. 

Fission is a byproduct of a cell’s ancestry. The vestiges of single-cell organisms are the reason why mitochondria can divide and replicate independently of the host cell.

According to a review published in Science, fission also “contributes to quality control” by regulating cell death during periods of stress. The article continues, “mitochondrial fission... play[s] critical roles in maintaining functional mitochondria when cells experience metabolic or environmental stresses.” Stressors like sun exposure or sleep deprivation can cause mitochondrial death and dysfunction. Fission helps clear away damaged and dead material, ensuring energy is spent on live tissue. 

Without fission to maintain the creation and destruction of mitochondria, cells can’t develop the working parts they need to energize their function adequately. 

4. Adenosine triphosphate (ATP)

This molecule IS energy. When you’re tired, you don’t need more caffeine. You need more ATP. 

ATP synthesis is like a highly advanced, microscopic game of hot potato. Our cells toss electrons from the carbs, fats, and proteins we consume over to oxygen molecules. Once these electrons are accepted by oxygen, it then picks up protons to form water—completing the process we know as ATP production.

According to a review published in Purinergic Signal, oxidation allows ATP to be stored in the bonds between molecules.

Once these steps are completed, cells throughout the body use ATP to power movement,  cognition, and all physiological processes.

5. Nicotinamide adenine dinucleotide (NAD+)

NAD+ (nicotinamide adenine dinucleotide) is found in every living human cell. NAD+ is a molecule that attaches itself to an enzyme to trigger and accelerate chemical reactions, also known as a coenzyme.

NAD+ supports many cellular processes. It supports cellular energy, defense and repair mechanisms within the cell. 

If mitochondria are the cell’s engines, NAD+ are the wires that connect the engine parts. Without this vital molecule, many of our biological functions would be rendered useless. From oral supplementation to dietary changes, there are several ways to support NAD+ production.

6. Citric acid cycle

According to Biochemistry, the citric acid cycle (also known as the Krebs Cycle) “is the central metabolic hub of the cell.”  

The citric acid cycle uses a series of chemical reactions to release energy, or ATP, stored in the matrix. Biochemistry shows, “the cycle is also an important source of precursors, not only for the storage forms of fuels but also for the building blocks of many other molecules such as amino acids.”

The building blocks of energy, known as precursors, are processed during this cycle. 

When a glucose molecule enters a mitochondrion, it undergoes a series of transformations where it gradually loses electrons. During this process, NAD+ is used to accept electrons and help produce energy in the form of ATP. 

The citric acid cycle is deeply technical and may be difficult for the layperson to understand. So, this is your takeaway: Within your mitochondria, molecules from food are turned into energy.

7. Cellular respiration

This complicated multi-step process uses ATP, the Citric Acid Cycle, and NAD+ to continually break down sugar from our food and drinks and turn it into the energy we need to stay healthy.

Despite its bad reputation in diet circles, sugar has a genuine energetic value to the human body. To obtain sugars while eating clean, snack on sweet fruits like pears and green apples. The healthy sugars and fibers will provide your cells with better energy.

Why is it important to know how your body creates energy? 

There are days where you sleep eight hours, have a balanced breakfast and a cup (or two) of coffee, and still feel drained before the day even starts.

All too often, the source of your exhaustion lies in your cells.

Impairment of any one of the seven mechanisms detailed above can result in noticeable fatigue. If you’re looking for better energy, don’t settle for quick fixes. Energy creation begins and ends at the cellular level, and there are ways to elevate productivity from within. 

Managing the stressors that inhibit mitochondrial function can maintain your vital energy. Limiting sun exposure or dehydration can help mitochondria thrive and reduce the energy spent on repairing damaged cells.  

Next time you feel a wave of unexplained exhaustion, consider your smallest parts. Equipped with newfound knowledge and solutions, you can work to combat fatigue cells-first.

In 1954, biochemist Dr. Denham Harman proposed the “Free Radical Theory of Aging,” hypothesizing that people age because our metabolic processes produce free radicals—unstable molecular compounds.

But later, in 2018, physiologist Dr. José Viña and his colleagues unveiled “A Free Radical Theory of Frailty,” arguing that free radicals do not necessarily dictate how long you’ll live but instead causes frailty in older people—a decline in wellbeing, unintentional weight loss, reduced grip strength, lowered walking speed, and difficulties standing. 

No matter which theory correctly explains why your body ages and deteriorates, many scientists agree that an increase in free radicals and a decline in the body’s ability to combat them causes a significant decline in your cellular health.

Free radicals and oxidative stress.

Free radicals are essentially unstable atoms that can damage cells, cause illness, and contribute to expedited aging. They can wreak havoc on DNA, cellular proteins, and cell membranes by stealing their electrons via a process known as oxidation. 

Oxidation is a normal, necessary process in the body. But when overexposure to free radicals complicates the usual oxidation process and produces oxidative stress, that’s when you’re in trouble. 

Oxidative stress occurs when an activity imbalance develops between the free radicals and antioxidants in your system. 

How do we get stressed on a cellular level?

Inside every living cell in your body, small organelles called mitochondria constantly generate the energy your cells need to function. Designated “the powerhouses of the cell,” mitochondria convert food into cellular energy. But during this metabolic process, mitochondria also produce a byproduct—free radicals. 

When your body needs a lot of energy, your mitochondria kick into overdrive, generating more free radicals. 

Factors like lack of sleep, lack of exercise, poor diet, drinking, smoking, and sun exposure can all lead to oxidative stress due to your mitochondria producing excess energy to counter these events.

How to fight cellular stress.

An effective way to reduce the effects of oxidative stress is to supplement your mitochondria with key micronutrients to help keep them in shape.

Foods that are rich in antioxidants, such as alpha-lipoic acid and coenzyme Q10, can help offset the antioxidant imbalance and keep your free radicals at a safe level. These can be found in fruits, vegetables, and other foods containing high levels of vitamins C and E.

Other micronutrients are harder to supplement with regular foods. Nicotinamide riboside is a particularly helpful micronutrient that is only found in trace amounts in milk and yeast. It supports our NAD+, a vital coenzyme needed for healthy cell function. 

A study in the scientific journal, Redox Biology, demonstrates that keeping NAD+ levels balanced helps counteract oxidative stress, by bolstering the body’s restorative cellular processes. 

Complimenting healthy foods with an NAD+ supporting supplement, like nicotinamide riboside, can help provide additional support for your cells from events that cause oxidative stress. 

It’s important to keep consistent with your intake. Preventive cellular care requires you to be proactive about your daily cellular nutrition.

Energy metabolism fuels every exercise you do—from running marathons to lifting weights. 

The body uses three different systems of energy metabolism: the phosphagen system, the glycolysis system, and the aerobic system. These systems work in harmony to create molecules of adenosine triphosphate (ATP), the body’s usable form of energy. 

Your cells do not store a huge supply of ATP molecules, so once you start contracting your muscles, you deplete your supply of ATP pretty quickly. Your cells are forced to start making more ATP to power your body immediately.

The phosphagen system

When your body needs ATP, you first use the ATP stored in your muscle cells. According to the Science Learning Hub, this energy stored for exercise only lasts three seconds.

Afterward, your muscle cells use their first system of energy metabolism, the phosphagen system. This process breaks down stored phosphocreatine to generate ATP. This energy provides another eight to ten seconds.

The glycolysis system

Once your muscle cells run out of phosphocreatine, they switch to the second system of metabolism known as the anaerobic glycolysis system. This process uses large stores of carbohydrates (stored in the body as either glycogen or glucose) to rapidly make more ATP—without the need for oxygen. 

The ATP produced lasts roughly 90 seconds, providing just enough energy for anaerobic workouts, like lifting weights or sprinting. 

The aerobic system

If your muscles need more ATP to endure a longer-lasting activity, the third system of metabolism, aerobic respiration, kicks in. This process breaks down your body’s glucose and fat reserves (created from carbohydrates, fats, and proteins consumed in the diet) to produce enough ATP to last several hours.

This is why extended exercises like running, dancing, swimming, biking are called aerobic workouts. 

Where do you get the energy? 

Every cell in your skeletal muscles contains anywhere from a few to thousands of mitochondria, tiny organelles widely known as the “powerhouses of the cell.” The mitochondria convert the energy stored in food into ATP.

However, your mitochondria cannot produce ATP or generate enough energy for you to even snap your fingers without one important coenzyme, NAD+—nicotinamide adenine dinucleotide. In a systematic review published in Skeletal Muscle, the need for NAD+ in muscle development is well-documented. 

As stated in the abstract, “The vast majority of studies indicate that lower NAD+ levels are deleterious for muscle health and higher NAD+ levels augment muscle health.”

All three systems of energy metabolism depend on NAD+.

In the anaerobic glycolysis system, NAD+ allows cells to oxidize glucose to pyruvate and quickly generate small amounts of ATP. 

In the aerobic respiration system, NAD+ extracts even more energy from sugars and fats and then reacts with proteins in the inner membrane of your mitochondria to drive the production of large amounts of ATP. 

In the phosphagen system, NAD+  is used to recharge after a workout. ATP produced with help through the aerobic and anaerobic systems recharges spent phosphocreatine.

Support your mitochondria for better exercise

If you’re looking for ways to support your physical endurance, running time, energy, and limit muscle soreness, you want to make sure your mitochondria continue to churn out ATP molecules. 

Mitochondrial supplements and NAD+ supplements can be one of many tools to help keep your mitochondria in shape.