Why Do We Age? The Science Behind the Aging Process

One minute, you’re scrolling through your phone looking for that infamous cake-in-the-hair photo from your kid’s first birthday. The next thing you know, you’re eight years deep in your camera roll wondering where the time went — and maybe noticing a few extra fine lines or gray hairs that weren’t there when all those pictures were taken.

Aging happens to all of us, but the process is a lot more complicated than adding another candle to the birthday cake. Changes are happening throughout the body over time, influenced by everything from our genes to the environments we live in.

So, why do we age? Let’s look at what science can tell us about the aging process and some of the factors that influence how our bodies change over time.

What Causes the Aging Process?

There isn’t one single cause of aging. Instead, aging happens as damage gradually builds up in our cells, tissues and organs over time. The body may become less efficient at repairing damage and maintaining the same level of function it did when we were younger.

Genetics play a role in this process, but they’re only part of the story. Hormonal changes, chronic inflammation, environmental exposures and everyday lifestyle choices can also influence how our bodies age.

What Happens to Our Cells As We Age?

Our cells are constantly working to repair damage and keep the body functioning. As we get older, however, some of those repair processes become less efficient, allowing cellular damage to accumulate over time.

These changes can affect how well cells function, divide and respond to stress. Eventually, those small changes at the cellular level can contribute to some of the physical changes and health concerns we associate with getting older.

How Do Genetics Affect Aging?

Our genes are one of the main components that impact how and why we age, with each individual’s unique genetic combinations playing a role in determining our overall lifespan. For example, some individuals are born with robust cellular repair mechanisms. This allows them to physically age at a slower rate than those that have less efficient DNA repair mechanisms.

How Do Hormones Change as We Age?

Our bodies use hormones to help us complete a myriad of functions, from regulating our metabolism and reproduction to influencing our mood and sleep patterns. Over the years, our hormone production declines.

Below, we discuss how lower numbers of certain hormones can exacerbate aging.

Estrogen and Testosterone

These well-known sex hormones are responsible for more than their fundamental role in helping us reproduce. They also play a part in regulating our bone health and cognitive function. As women age, their estrogen levels lower. This makes them more likely to experience signs of aging in the form of bone loss. For aging men, however, the loss of testosterone can decrease muscle mass and libido, contributing to declines in overall physical function.

Growth Hormone (GH)

As you might expect, GH is crucial during our formative years, as it regulates our metabolism and body composition as we grow into our adult bodies. But like with most internal processes, GH declines with age.

In turn, our metabolic rate may decrease, leading to an accumulation of fat. Depleted GH production can also impair our bodies’ ability to repair tissue, which can contribute to age-related declines in muscle mass, skin elasticity and bone density.

How Does Chronic Inflammation Affect Aging?

When we’re young and get sick or scrape a knee, our bodies get straight to work to repair the damage by initiating an inflammation response. That’s because, as children, our cellular repair capabilities are in their prime.

As adults, however, our bodies sometimes initiate low-level inflammation even when there’s no infection to fight against. That inflammation can last for days, months or even years at a time. This continuous low-grade inflammation causes what’s known as inflammaging, which makes some individuals more prone to certain age-related diseases and accelerated aging.

How Do Environmental Factors Affect Aging?

It’s hard to pass up some of life’s simple pleasures, like soaking in the warm rays of the summer sun or treating yourself to an extra glass of wine. However, some of those indulgences contribute to the aging process.

For instance, the sun’s ultraviolet rays introduce unstable molecules, called free radicals, into our skin. Over time, free radicals have the potential to damage your DNA, which can cause premature aging, wrinkles and cancer.

Other environmental factors that can cause signs of aging include air pollution and exposure to carcinogens, such as cigarette smoke.

How Do Lifestyle Choices Affect the Aging Process?

We can’t control how our genes impact the aging process, but we can control some of the lifestyle choices that affect how we age. Below, we explore how some of these can impact you negatively if neglected:

Diet
A diet that consists largely of processed foods, unhealthy fats and sugar can accelerate internal cellular damage. This increases the likelihood of developing diseases that speed the rate of aging, such as diabetes, obesity and cardiovascular disease.
Physical activity
A sedentary lifestyle can prematurely contribute to muscle loss, decreased mobility and age-related diseases.
Sleep
Your body needs ample sleep (at least seven hours) to function at maximum capacity. Getting less than that for an extended period can disrupt your body’s natural circadian rhythm, increasing the risk of accelerated brain aging, a condition that occurs when your brain ages faster than your chronological age. This can lead to cognitive decline and memory impairment.

Can You Slow Down the Aging Process?

You can’t stop aging altogether, and some of the factors that influence it are outside your control. But the choices you make throughout your life can affect how well your body functions as you get older.

Regular physical activity, a balanced diet, adequate sleep and avoiding tobacco can all support healthy aging and help reduce the risk of many age-related health conditions. So, while there’s no pause button for the aging process (unfortunately), there are ways to support your health along the way.

And if understanding why and how our bodies age has only made you more curious, you can take that interest even further.

Unravel the Body’s Many Medical Mysteries at the University of Florida

UF’s College of Medicine is proud to offer several entirely online graduate programs that focus on medical physiology. Each program enables you to embrace your passion and gain the foundational knowledge and skills to begin a career in medicine, from becoming a physician to pursuing a role as a clinical scientist — and so much more.

Our range of online graduate degree and certificate programs include: