Mitochondria are microscopic particles found inside almost all living cells. They’re tiny, but essential for life. When they were first detected in the 1800s they were thought to be inert, like tiny bits of cartilage, for which they were named. A mitochondrion [pronounced might-oh-con-dree-on] is about the size of a bacterium. Several thousand are located in almost every cell of our bodies.
It took over a hundred years to begin to understand their importance, and scientists are still learning more about them as they dig more and more deeply into molecular and cellular biology. They are sometimes called cellular powerhouses because they are the energy factories of the cells, producing about 95 percent of the energy we use in our lives every day.
Each of the trillions of cells in your body requires oxygen and glucose to survive. The mitochondria are tiny chemical processing works in every cell that carry out the process of cellular respiration, converting oxygen and glucose to adenosine triphosphate (ATP). This provides the energy that cells must have to carry out all their functions, and that we must have for everything we do.
How many mitochondria must cells have to do their work? This depends on the type of cell and its energy requirements. As you might guess, muscle cells require lots of energy to carry out their work, so they have more mitochondria per cell than most other tissues. Most muscle cells have several thousand mitochondria per cell, generating the energy that the muscle uses to do its work. Heart muscle cells have the richest supply of mitochondria because the heart beats 24 hours a day. Without them, we would die.
Virtually every cell in the body has some energy requirement on which our lives depend. Our gut cells must have energy to do their work of digesting food and moving intestinal contents along through the action of peristalsis. Our liver, kidney and brain cells all require energy to do their work. Our blood vessels must have energy to move our blood along its 60,000-thousand-mile route. All of these vital organs depend on mitochondria for the energy they need.
Exercising on a regular basis stimulates our mitochondria to multiply inside our muscle cells to generate more energy. Because of this, elite athletes may have twice as many mitochondria in their muscle cells as most people. Even so, we can all benefit from the amazing ability of mitochondria to respond to higher energy requirements. The key point to remember is that the best way to gain more energy is to make good use of the energy capacity we already have!
Unfortunately, the reverse is also true. If we don’t use our energy capacity, we lose it. That’s a big reason why a sedentary lifestyle undermines good health. Mitochondrial malfunction contributes to many serious health problems today, such as type 2 diabetes, obesity and premature aging. In view of this, it simply makes good sense to support mitochondrial health to the best of our ability. Research shows that physical activity, healthy eating habits, and meditation all help support mitochondrial health.
Without delving more deeply into all this now, I’ll conclude by noting that moderate physical activity improves health in many ways. One of these ways is to support the quadrillions of mitochondria in our bodies, a matter of key importance to our health. I’ll explore other factors important for mitochondrial health in future newsletters. Today, our focus is on physical activity. To keep your mitochondria happy and healthy, devote at least thirty to sixty minutes to some form of moderate exercise every day.
Ed Dodge, MD, MPH
This post was published first in Dr. Ed Dodge’s Wellness Newsletter, Volume VI, No. 7 • July 19, 2014.