6.) Can we measure our individual aging trajectories, or, a kind of "biological" age (i.e. how young is our body, are our organs and tissues and our cells?) that differs from our chronological age (i.e. how many years have we lived)? What is the current state of molecular biomarkers of aging to measure this in human aging, e.g. #epigenetic marks, plasma proteomics or #telomere length?

7.) Opposed to these molecular biomarkers, there is a number of physiological biomarkers that reliably predict individual aging trajectories, as well as morbidity and mortality risks. These are relatively easy to measure and interpret (and much cheaper!). Ample human data exist, across all age ranges, in healthy individuals and patients, both sexes and different ethnicities. Curiously however, they are often neglected in contemporary discussions. Examples include #VO2max as a measure of cardiorespiratory fitness (and endurance capacity!), body composition (relative #muscle and #fat mass, as well as fat distribution), muscle #force and #power, the amount of leisure time physical activity, or frailty indices such as gait speed.

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