Mitochondria are essential for healthy aging. Not only do they generate around 90 percent of all energy (ATP) produced in our body, they also participate in many cellular processes essential for healthy cell function. In fact, mitochondrial dysfunction is one of the hallmarks of aging. Modern theories of aging fall into two main categories: “programmed aging” and “aging as damage accumulation”. Programmed aging theories argue that aging follows a genetically encoded timeline—just like development in childhood and adolescence does—that unravels as changes in gene expression: as we age some genes switch on or become overexpressed, while others switch off or become underexpressed. Damage accumulation theories argue that aging is primarily driven by cumulative damage to proteins, DNA, mitochondria, cells, and tissues of our body as a consequence of their activity.
But these theories and the processes they describe are not necessarily mutually exclusive. Both programmed aging and damage accumulation occur at the cellular level, and each may amplify the effects of the other (i.e., changes in gene expression may accelerate damage accumulation, while damage accumulation may affect a cell’s gene expression). Over enough time the result is a big difference between “young you” and “current you.” One of these differences is that your cells were able to produce more energy when you were younger. They also communicated better with other cells, were better able to adapt to stress, and had less cellular damage. While many things go wrong as the human body ages, the roots of the problem are at the cellular level. And, within cells, mitochondria play a key role in aging processes.
But cells have a number of mechanisms that slow down aging and senescence. And again, mitochondria take center stage: selectively eliminating dysfunctional mitochondria (mitophagy) and replacing them with new mitochondria (mitochondrial biogenesis) is one of the key mechanisms that helps our cells—and us—stay biologically younger. But what exactly are the functions of mitochondria and how does mitochondrial health affect aging?
Mitochondria are specialized structures found in cells. They participate in many cellular processes, but their most important function is to extract the energy that is stored in the chemical bonds of nutrients (in the form of electrically charged particles called electrons) and transform it into a form of energy that cells can use to power their activity. This form of energy is a molecule called ATP (from adenosine triphosphate) and the process is called cellular respiration.
Because mitochondria generate around 90 percent of all ATP produced in our body, they are known as “the powerhouse of the cell.”
Keeping mitochondria healthy, with proper function and structure, is essential for cells to work optimally. When cells are fueled efficiently and biological pathways run smoothly we enjoy better health. But when mitochondria are dysfunctional, they start to accumulate damage and cellular processes start to gradually get disrupted.
From a bottom-up perspective, mitochondrial fitness is essential for our health in general. Because of this, it isn’t a surprise that loss of mitochondrial function is a hallmark of aging and many age-related disorders, whereas maintenance of mitochondrial fitness is linked to increased healthspan (the length of time that a person is healthy and functional—not just alive) and longevity.
The good news is that there are plenty of science-backed lifestyle changes to help boost mitochondrial function. Here are four of our favorites.
4 Science-backed ways to rejuvenate mitochondria
Exercise. Exercise is one of the most powerful habits for longevity. Exercise requires a great deal of energy to power our muscles. That puts a burden on muscle mitochondria, signaling energetic demand to the rest of the cell. Muscle cells respond by producing more mitochondria and more mitochondrial enzymes, helping to delay the age-related decline in mitochondrial activity and muscle health.
While many types of exercise can boost mitochondrial function, HIIT fitness routines, in moderation, are especially advantageous to cell function. In a study from the Swedish School of Sport and Health Sciences, 11 healthy volunteers were put through regular HIIT sessions on an exercise bike (which involved intervals of all-out pedaling followed by short periods of rest). The result? Improved performance and increased mitochondrial production.
Cold Exposure. There is evidence that cold therapy improves mitochondrial health through a process known as “mitochondrial biogenesis,” or in other words, increasing mitochondria production.
Shivering releases heat in the process of burning fuels and using ATP to power muscle contraction. Shivering thus recruits mitochondria to indirectly generate heat. Therefore, cold exposure in the form of cold showers or cryotherapy can boost mitochondria to keep us warm.
Heat Exposure. Heat can also trigger beneficial biological responses. Heat acts as a mild stress signal and triggers cell responses that promote adaptation.
One of the main agents of that adaptation are mitochondria as it has been shown that heat stress triggers beneficial adaptive responses in mitochondria that increase their functional capacity. This stands in line with studies showing that routine sauna bathing can improve endurance performance and reduce the risk of cardiovascular diseases.
Calorie Restriction. Reducing calorie intake (through fasting diets, for example) is one of the most successful approaches to enhance longevity. This success can be attributed, at least partially, to an increase in mitochondrial bioenergetic efficiency.
Neurohacking tip: Taking one or more calorie restriction mimetics—plant compounds like resveratrol that cause cells to respond in some of the same ways as they do while fasting—appear to offer some of the physiological benefits of limiting calories without actually having to eat less (or be hungry). To explore the science behind fasting we suggest reading an article published in Science entitled, A Time to Fast.
By rejuvenating mitochondria, we are supporting the optimal functioning of pretty much every cell and system in our body. Boosting mitochondria can contribute to greater lifespan and healthspan.