Chronological Aging vs. Biological Aging


When asked how old you are, you likely answer based on the number of years that have passed since you were born. That would be your chronological age and is simply your age in years.

Yet you may be 40 but your doctor tells says you the body of a 21-year-old. This would be considered your biological age, regardless of how many years ago you were born.

Your chronological age will always be an easy-to-determine number, while your biological age depends on a number of variables that can change on a continuing basis.

The difference between the two can be surprising 

What is chronological aging?

Your chronological age is the amount of time that has passed from your birth to the given date. It’s your age in terms of years, months, days, etc. This is the primary way people define their age.

It’s also a primary risk factor for chronic diseases, mortality, and any impairments to bodily functions, such as hearing and memory.

What is biological aging? 

The basic idea behind biological aging is that aging occurs as you gradually accumulate damage to various cells and tissues in the body.

Also known as physiological or functional age, biological age takes into consideration a number of factors other than just the day you were born.

Some of these include:

  • chronological age
  • genetics (for example, how quickly your body’s antioxidant defenses kick in)
  • lifestyle
  • nutrition and supplementation
  • diseases and other conditions

For example, you may have a calendar or chronological age of 65, but because of a healthy and active lifestyle, your body is physiologically more similar to someone with a chronological age of 55. Your biological age would, therefore, be 55.

There are a number of validated modalities and measurement techniques that can actually determine at what age your body is functioning.

“In the end it’s not the years in your life that count, it’s the life in your years.”