How Old Are You Really? The Science of Biological Age
We all know our age by the calendar. But what if your body was younger… or older… than the number on your birthday cake?
I used to work at Karolinska Institutet in Sweden, one of the world’s leading medical universities. Their researchers have been studying biological age, a way of measuring how your body is really aging, based on factors like metabolism, fitness, and cell health. Unlike chronological age, which is just the number of years you’ve been alive, biological age reflects how well your body is functioning and how likely you are to enjoy a longer, healthier life.
Chronological vs Biological Age
Chronological age: The number of years you’ve been alive.
Biological age: A reflection of how well your body’s systems are working. Two women could both be 40 — but one might have the health markers of a 30-year-old, while the other’s body may show signs of being closer to 50.
What Affects Biological Age?
According to KI’s research, lifestyle choices have a huge impact on whether you age faster or slower than average:
Exercise & muscle mass: Staying strong slows aging.
Nutrition: Balanced diets protect against disease.
Sleep & stress management: Poor recovery ages the body faster.
Genetics: They play a role, but far less than lifestyle.
Why This Matters for Women After 30
This is exactly why I focus on longevity coaching with my clients. After 30, your body changes — metabolism slows, hormones shift — but that doesn’t mean you can’t stay biologically “younger.” With strength training, smart nutrition, and recovery, I’ve seen women lower their biological age markers and feel better in their 30s and 40s than they did in their 20s.
My Final Thoughts
Your birth certificate tells you one age. But your lifestyle tells another. The exciting part? You have more control over your biological age than you might think.
Want to learn more? Check out Karolinska Institutet’s research here: How old are you really?