In terms of your health, perhaps nothing. CNN reports on work by Dr. Morgan Levine of Yale Medical School on a new metric for age based on biology, not cycles around the Sun.
Basically, everyone has two ages: a chronological age, how old the calendar says you are, and a phenotypic or biological age, basically the age at which your body functions as it compares to average fitness and health levels.
The assessment using information captured during normal blood tests associated with physical exams.
Dr. Levine argues that there are nine biomarkers taken in a simple blood test that seem to be most closely associated with lifespan.
What makes this exceptional is that these biomarkers are things, like blood sugar, that are to some extent under the patient’s control. You have the ability to influence how long you live.
The next step would be to extend these metrics to include measures of quality of life.