Shayna Busch

The Death of Age-based Death

How old are you?

Good. That answer should be equal to the number of years since your birth. Yes, also called your age.

Are you human? Well then in one year you will be one year older, one year closer to your demise.

What?! Well at different ages you have a different probability of death. As your age increases, so does this probability of mortality. Each year you can survive, or demise. Yet there is great variability in the rate of disability. Clearly death is not just based on age alone.

Why do things age? Plants, animals, all living things experience physiological decline over time, called senescence. When people say aging, they often mean senescence. I try to understand population patterns of senescence. It is much easier to predict senescence on the population level than the individual level.

The key question is what is the best predictor of mortality rates? Chronological age? Diet? Exercise? DNA? Cellular decay? Metabolism rates? Weight?

Animals might use mass as a mortality indicator, plants perhaps use perimeter. Physiological stress, lack of sunlight, or harsh conditions might age a plant beyond its years. Therefore, your increasing age shouldn’t move you to tears. If there were 10 possible stages you could be in, based on stress, genetics, or general health, that might be a better correlate of mortality rate.

So next time I ask you your age, it might be more appropriate to respond with stage.