Aging: Terms and Theories

by Nina

I’m old enough that I’ve started to focus on doing some of the things I’ve always wanted to do but never got around to. Some are big (writing a novel!) and some are rather trivial. One of the more trivial things that I somehow never got around to was listening to my husband and fellow blogger, Professor Brad Gibson, give a talk. He’s kind of infamous for talking really fast, jumping around the room a lot, and packing his talks with lots of information and jokes. Recently I got the perfect opportunity to finally check him out in action when he gave a talk on his research on aging and age-related diseases at a scientific symposium.

And, yes, dear readers, Brad was a hyper and funny as I’d been told. And since you haven’t heard from Brad in a while, I thought I’d take the opportunity to tell you a little about what I learned from his talk. He began by defining some basic terms that I thought might be useful for you to hear as well.

Aging is the process of a system’s deterioration over time.

Aging and Age-Related Diseases is the (mostly) undefined relationship of “normal” aging and diseases known to be highly associated with aging, such as cancer, Alzheimer’s and Parkinson’s diseases, and type 2 diabetes.

Healthspan is the period during a person’s life during which they are generally healthy and free from serious or chronic illness. This is what most researchers in the aging field are focusing on increasing (as opposed to lifespan).

Compressed Morbidity is “The compression of morbidity occurs if the age at first appearance of aging manifestations and chronic disease can increase more rapidly than life expectancy. — James Fries (My translation: compressed morbidity means shortening the period of ill health that precedes a person’s death.)

Scientists understand that healthspan and compressed morbidity are important concepts because what would extending life be worth if it only meant 20 more years of serious illness and disability?

Muddy Road by Brad Gibson

Brad did make a number of jokes, but the thing that made me (and some of the audience) laugh the most was a slide about the theories of aging. He prefaced this slide by saying to his audience, as he’s said to you, that when he first came to the Buck Institute for Age Research, he assumed that scientists had a basic understanding of aging. Instead, he found that very little was currently known about aging. Then he showed a slide listing the following theories (those in bold are theories he considers the most compelling).

What is Aging?

Wear and Tear theory
Error and Repair theory
Neuroendoncrine theory
Redundant DNA theory
Genetic Control theory
Free Radical theory
Caloric Restriction/Nutrition
Cross-Linking
Waste Accumulation
Gene Mutation
Limited No. of Cell Divisions
Rate of Living
Hayflick’s Limit theory
Order to Disorder (entropy)
Death Hormone
Thymic-stimulatory theory
Mitochondrial theory
Autoimmune theory
Antagonistic Pleiotrophy
Senescence and Inflammation (SASP)Telomere Shortening
Others (Insulin, mTOR, etc.)

I don’t know about you, but I had no idea there were so many theories of aging and neither did most of the scientists in the room! (That's certainly something to keep in mind when you read about the latest anti-aging diet or supplements that are based on some theory of aging that some expert claims is fact.) Of course, while scientists don’t yet know the why of aging, we are all familiar with many of the what’s. For example, most of us understand that human beings typically lose strength and flexibility as they age (things yoga can help with, by the way). And I hope to have some posts from Shari Ser on this subject—what happens to us as we age—in the near future.

The next slide made people laugh, too, because it showed a worm looking young and fresh at 3 days and then old and wrinkly (for real) at 10 days