Some people seem to age faster than others. For example, 10 years after graduation, one classmate might look far younger than the rest, while another might look a decade older.
Chronological age is simply how many years someone has been alive. We use it all the time to celebrate birthdays, fill out forms for doctor appointments, or even get a drink at a bar. Everyone born in the same year has the same chronological age, no matter how young or old they appear.
Biological age, however, can be different for everyone. It gives a better idea of how the aging process varies from person to person.
Some 50-, 60-, and 70-year-olds may look and feel much younger, while others might not.
Scientists can measure these differences by looking at age-related factors like skin elasticity, blood pressure, lung capacity, and grip strength.
People with a healthy lifestyle, good living conditions, and lucky genetics tend to score “younger” in these tests and are considered to have a lower “biological age.”