Measuring Aging: Biological Age and Clocks Explained

Is age truly just a number? Or is it based on something more?

Well, your biological age definitely is based on something more! Biological age is the output of a biological clock; it’s a critical concept and practical tool for aging research. It’s helpful to understand what your biological age means, what influences it, how it differs from your chronological age, and how exactly we derive it.

Biological Age vs Chronological Age

Everyone ages at a different pace, so it’s important to distinguish your chronological age from your biological age.

Your chronological age is the number you celebrate every birthday, which you have no control over. Your biological age, on the other hand, is more persuadable. It’s reflective of your overall health and changes in response to your lifestyle and health status.

A healthier diet, frequent exercise, and regular sleep can actively reduce your biological age. To determine biological age, longevity researchers first had to identify standardized metrics, or biomarkers, of cellular aging.

Aging Biomarkers

Aging biomarkers are well-researched fundamentals of aging at the cellular level; they react to aging and age-related ailments in a measurable way. These aging biomarkers are used to understand and develop what we call, biological clocks which in turn, measure and calculate our biological age.

Analyzing aging biomarkers can enable the early diagnosis of several diseases. A firm understanding of your aging biomarkers and cellular health can actually help you take steps to fight age-related diseases such as cancer, cardiovascular illness, and neurological disorders¹.

One of the key biomarkers of aging is epigenetic changes. Epigenetic changes have been used to produce several biological clocks.

Epigenetic Changes

The epigenome is the layer of molecules, such as methyl (CH3), that regulate gene expression without altering our genetic code. While our genome is constant from birth, our epigenome is flexible and dynamic, heavily influenced by our environment and lifestyle².

DNA Methylation

DNA methylation is a fundamental concept in epigenetics.

Gene expression refers to the level of protein production coming out of a gene. A gene can only produce proteins when specific enzymes bind to its DNA. If we wanted to turn off a gene so that it stops producing proteins, we’d have to prevent enzymes from binding to its DNA. Attaching methyl groups to a gene’s DNA makes it difficult for proteins to bind. So, increasing DNA methylation levels can effectively lower protein production and therefore, gene expression³.

Ideally, we want lower methylation levels on genes with protective effects such as tumor suppressor genes, and higher methylation levels on genes that may produce negative effects, like tumor promotor genes. However, as we age, DNA gets damaged and subsequently repaired. DNA repairs are rarely perfect and often result in different methylation patterns. These critical changes can accelerate aging. In fact, most of the age-related changes we experience are consequent of epigenetic changes⁴.

Biological Clocks

There are several epigenetics-based clocks that analyze DNA methylation patterns to determine your biological age. Machine learning analysis of DNA methylation is also indicative of overall health, certain disease risks, and lifestyle practices^5,6.

There are several epigenetic clocks, including the PhenoAge clock, the Hannum Clock, and GrimAge, considered the gold-standard aging clock developed by Dr. Steve Horvath at UCLA – that’s what we use at FOXO! Some clocks focus on blood sample readings, some use saliva, while others rely on cells in a particular tissue. Each of these biological clocks has its own strengths and weaknesses⁷.

Now that you understand biological age and clocks, you can refresh your outlook on aging as a whole! The very best part about biological age is that it can be influenced. How you treat your body, is how it treats you; biological age verifies that.

Takeaways

• While your chronological age is the number you celebrate every birthday, which you have no control over, your biological age is more persuadable.
• A healthier diet, frequent exercise, and regular sleep can actively reduce your biological age.
• One of the key biomarkers of aging is epigenetic changes. Epigenetic changes have been used to produce several biological clocks. Machine learning analysis of our epigenome is also indicative of overall health, certain disease risks, and lifestyle practices.
• There are several epigenetic clocks, including the PhenoAge, the Hannum Clock, and GrimAge, considered the gold-standard aging clock developed by Dr. Steve Horvath at UCLA – that’s what we use at FOXO!