Biological age
Biological-age tests: what a younger number actually establishes
A repeatable result, a useful risk signal and a proven treatment target are three different achievements.
From Theo Bennett
Fitness
VO2 max and longevity: strong associations, careful conclusions
Fitness predicts outcomes in cohorts. That does not turn a watch estimate into a personalized survival forecast.
Function
Grip strength is a useful signal. Function tells a fuller story.
A stronger squeeze predicts better outcomes in populations, but the practical goal is preserving what you can do.
Glucose
CGMs without diabetes: feedback is not yet an outcome
A glucose graph can reveal patterns. It cannot by itself establish that you need treatment or that a flatter line improves longevity.
Body composition
DEXA body composition: the precision behind the percentage
A scan estimates tissue compartments. Preparation and repeatability determine whether a small change is believable.
Sleep
Sleep trackers: useful patterns, uncertain stages
A wearable can help describe your routine while leaving important sleep problems unresolved.
Biological age
Epigenetic clocks: age, risk and pace are different claims
The training target explains why two credible clocks can give you different answers.
Preventive testing
Preventive blood panels: when more tests change a decision
The useful unit is a well-supported decision, not the number of biomarkers in a membership.