Historically, the only age that mattered was our “chronological age,” defined by our birthday. Pretty simple.

But, as Dr. Mark Hyman suggested on our online Fireside Chat a few months ago, he may be 63 years old chronologically, but he’s 43 biologically when taking into account specific biomarkers, physiological functions, and overall health indicators. More and more of us are obsessed with our “biological age.”

Then, others focus on "metabolic age" based on factors such as body composition, basal metabolic rate, and metabolic markers. Metabolic age measures how well an individual's body processes and utilizes energy, and it can provide insight into their overall metabolic health. It's geeky!

And if I haven't confused you enough, let me introduce you to "cognitive age," or how a person's mental or intellectual capabilities compare to what is typically expected at a specific age (sometimes, I think mine is 12 years old). Cognitive age is often used to determine whether dementia may be on the horizon.

Finally, let’s focus on something that MEA specializes in: our “psychological age,” which was popularized by Ellen Langer’s work as chronicled in this New York Times magazine story (“What If Age is Nothing But a Mindset?) a decade ago. As Yale’s Becca Levy has shown, when we shift our mindset about aging from negative to positive, we gain 7.5 years of additional life. So, who knows, maybe psychological age is the most important metric for us to consider for a long, happy life.

So, the next time someone asks your age, make sure you know which age they’re talking about.