The Relationship Between Cellular Health & Human Performance
Cells are a fundamental component of human life. In fact, the body is composed of trillions and trillions of cells—close to 30 trillion according to recent estimates. Because cells are the basic units of tissues and organs, everything we do as humans—from thinking and breathing to running and competing—involves our cells. So how exactly do our cells “work” for us?
Just as the human body has separate organs like the heart and liver, the cell has separate “organelles,” which play a key role in maintaining cellular health by regulating different processes like cellular energy, structure, and function.
Energy in the cell is formed by producing a molecule called adenosine triphosphate, or ATP. ATP can be thought of as cellular fuel, similar to gasoline for a car. In other words, just as a car engine uses gasoline to drive and function, many different biochemical events use ATP to generate energy to maintain cellular structure and function.
And just as burning gasoline in a car engine generates toxins like carbon monoxide, burning ATP produces cellular toxins called reactive oxygen species (ROS), also known as free radicals. This becomes important when talking about cellular health, because ROS is necessary for many functional roles like cell signaling; but too much of it can cause inflammation and damage to the cell.
As the common saying goes: it’s all about balance.
Energy substrates: what makes a cell tick?
Sugars & Fats
Of course, ATP is not created from nothing, and the cell needs something else in order to produce ATP. This is where glucose (i.e. sugar) comes in. Sugar gets a bad rap in the health and wellness industry: but it’s absolutely essential. Glucose is mainly derived from carbohydrates in our diet like grains and pasta, then broken down into a carbon source that is used by the cell to make energy.
During periods where glucose is low or unavailable, our cells are actually equipped with machinery that is necessary to burn another energy source, known as a ketone, for energy. Ketones are carbon-based building blocks of lipids (i.e., fats) and are used by the cell to make energy in a similar way that it uses glucose.
You may be thinking, gasoline? This is 2022. Well, how about we think of a cell as a hybrid car in this sense. Hybrid cars primarily run off energy made by the combustion of gasoline, but they also have the functionality to run off battery power. Similarly, the cell is primarily built to run off energy made by sugars, but it can adapt and run off energy made by ketone fats if needed.
Cellular health and human functions
We’ve covered the source of the energy, so you can imagine where this may be going. As humans, all of our activities and functions require energy; simply existing, breathing in oxygen is a method of consumption that puts our cells to work. Let’s talk more about how cellular health directly relates to those very human functions and performance.
Physical performance and recovery
There are quite a few ways by which cellular health becomes important for physical performance.
For example, think of when you’re lifting weights at the gym. When you perform a bicep curl or are running on the treadmill, your muscles get the signal to contract. Well, the body needs ATP in order to contract those muscles, and you guessed it; working out burns a whole lot of ATP. In fact, the depletion of ATP is one of the reasons we get tired during exercise, and is why it is important to rest between sets (and workouts).
Similarly, an adequate level of salts like sodium and potassium are required for nerves to conduct signals properly. Muscle contractions can only be achieved with proper signal conduction, so ensuring you have a healthy salt balance is essential to a successful work out. This is one of the reasons why electrolyte-rich drinks are recommended during and after intense exercise.
Performance isn’t just about hitting stats in the gym–it’s a continual process. What good is one good workout, if you injure yourself in the process and miss weeks of more exercise? Cellular health also plays a key role in the recovery process after being active.
For example, when you exercise, your muscles burn a lot of ATP, which consequently causes an increase in the number of free radicals that are produced.
If cells cannot sufficiently remove free radicals from the cellular environment, this can significantly damage cells and cause dysregulation in both autophagy and inflammation. Rest and recovery are important components during exercise that allow a cell to remove these toxins from the cytosol.
Day-to-day performance: cognition and sleep hygiene
Much of what we do day-to-day involves our cells as well. From focusing on work projects, to thinking about dinner options, to planning the fastest way to the office—all of these require optimal health of our brain cells, known as neurons.
In fact, there are many studies that have shown that increased ROS is linked to cognitive impairments in many species, and that free radicals can impair the ability of neurons to communicate with each other.
When free radicals build up inside the cell, this can cause “oxidative stress” to the cellular environment. In turn, oxidative stress has been linked with several impairments related to cognition as well, including object and spatial memory functions.
What’s more, antioxidant compounds have been shown to block impairments caused by oxidative stress, which just goes to show how bad free radicals really are for our brain health.
Finally, just as cellular health is important during the day, it also appears to be very important for a restful night’s sleep.
As an example, studies have shown that sleep disorders like sleep apnea are linked to high levels of ROS and oxidative stress markers. While other studies have shown that the time spent sleeping may be directly related to the level of oxidative stress in our bodies.
These studies go on to suggest that sleep provides a defensive mechanism against oxidative stress, and that by optimizing cell health to efficiently remove oxidative stress, we need less time to get a restful night’s sleep!
Cellular health as we age: focus on health span, not lifespan
As science continues to evolve, it is becoming evident that cellular health is a necessary factor when considering quality of life as people age. In fact, it is becoming clearer that cellular health declines as early as 30 years of age, and progressively worsens thereafter.
For instance, one study examined samples taken from people 30 to 64 years of age for changes in the ability of mitochondria to produce energy. The authors found that as people aged, this ability to produce energy decreased, suggesting that age is a key factor in maintaining cellular health.
Historically, medicine has aimed to improve the lifespan of an individual by treating age-related diseases. However, the issue with this approach is that after successful treatment of one disease, it is likely that an older individual will experience a subsequent morbidity (e.g., disease).
Thus, while lifespan may be increasing among the older population, quality of life may not be particularly adequate, given the possibility of multiple diseases experienced one after another or because of multimorbidities (three or more diseases presenting at the same time) that are more typical in the later years of life.
As of late, the idea of healthspan has become a popular term among gerontologists, or scientists who study the mechanisms and processes of aging.
Healthspan is a term used to describe the quality of life an individual experiences as they age. As such, improving the healthspan means to enhance the duration of health and independence as people grow older.
One way that researchers are looking into increasing the healthspan is by investigating why cells stop dividing. After all, cell division is the basis of tissue growth and declines as we age. Cell division is extremely high when we are young, which gives a youthful appearance to the skin. But as we age, the rate of cell division tends to slow down, which can lead to wrinkles and less elastic-looking skin.
The state when cells stop dividing, but continue to maintain metabolic activity, is called cellular senescence. It is similar to other types of cellular fate like proliferation, necrosis, and apoptosis.
Cellular senescence has been related to many age-related diseases and is thought to play a key role in many age-related outcomes like chronic inflammation, arthritis, memory impairments, and so on. As such, scientists have been investigating ways to target senescent cells in order to reverse the effects of aging and to optimize healthspan.