Contemplating Longevity Part 3: Evolution Based Theories of Aging

What was the first moment you realized you were getting older?

A memory for me was when I went into the training room at college after basketball practice. As a freshman, I wondered what all these guys were doing laying down on training tables, sitting in ice baths, and having things wrapped and taped. Four years later, I found myself appreciating the services of the trainers to soothe aching joints and muscles.

Now, the grind of competitive athletics certainly introduces some wear and tear, but even for non-athletes the progression of age seems inescapable.

There is a Norse myth that tells of Thor wrestling an old woman named Elli. The harder he struggles, the stronger she seems. Eventually, even mighty Thor submits, and finds out that this elderly woman is 'old age' herself.

Aging is not a uniquely human experience, although some organisms age in dramatically different ways. The naked mole rat, tortoises, redwood trees and the 'immortal' hydra come to mind.

Humans have made remarkable gains in life expectancy. More people are living for more years. But the rate of aging, think of the point in life we see wrinkles and gray hairs appear, has not changed very much at all. Why is that?

The scientists that are looking under the hood have a few ideas. From studying other creatures, and looking at various unique versions of homo sapiens, we are starting to build a knowledge base that can give us some insights.

From this knowledge we are starting to show that in some cases we can slow down or delay the aging process. At the very least, we get a better understanding of things that can speed it up (which most of us want to avoid).

It is important to note that there is not one universal theory of aging, rather there is a universe of aging theories.  In some ways we are like the blind priests holding different parts of the elephant.

Let's take a quick tour through the aging universe and see what's out there.

Contemplating Longevity Part 2: To Infinity and Beyond

In Part 1, we considered how gains in childhood mortality affect the calculation of life expectancy, as well as how birth conditions influence your odds of living to an old age.

Now, let's look at some interesting things at the other end of the age spectrum.

First, let's visit the "mortality plateau".  This is not an actual rock formation (at least I couldn't find one, the closest I got was the "Death Canyon Shelf")

What I am referring to is an intriguing phenomena at old ages.

Contemplating Longevity Part 1: The Importance of Starting Strong

Like every fire begins with a spark, every life has a starting point.

For now, let's define our starting point as birth. And let's also consider the first few years.

I want to look at this from two directions.

First, from a measurement perspective. You may hear news headlines about movements in life expectancy.  Fluctuations from one year to the next are usually fairly small.  But if you look back a few decades, the gains have been huge in several countries.

It may seem counter intuitive, but a lot of that lift over the past few decades has not been a function of life extension at older ages.  Instead, longevity will go up, sometimes dramatically, when more little humans survive their first few years.

Second, do your birth circumstances predict your longevity?  To what extent? And if they do, is there anything you can do about it?

Grab your marshmallows and graham crackers and let's cozy up to the fire and contemplate longevity!

Is Death Random or Predictable?

Another way to ask this is: is it more like a casino game or a battery?

Let's visit each position.