Predicting Longevity

There is a non-zero chance you die today.

Let’s say you have the ability to live to be 120 if everything goes as planned. That is 43,800 days. So if you’re 37, you’re chance of dying is 1/30,295. Every day you are alive, the denomination of that fraction goes down, and the likelihood of your death goes up.

We’ll say it’s 1/30,295-1, 1/30,295-2, and so on.

But that’s assuming you live to be 120. The truth is, it’s unlikely you live to be 100. And even scarier, you don’t know how long you’re going to live. So the equation looks more like this:

1/x-n

where x is the number of days you have left

We are aware of the fact that n is going up. But it’s hard to come to terms with the fact that x is stationary. Maybe it’s not. 

Let’s say that every day you workout, you increase x by 0.25. And every day you eat healthy, you increase x by 0.25. So you can slow down your demise, but you can’t stop it.

If your normal x was 60 years. You have 21,900 days. Exercise could theoretically increase your x by 5475 days or 15 years. Eating healthy could add another 15 years. So you could stretch things out 30 years. You could live to be 90. That’s theoretically, and if you exercised and ate healthy every single day.

But every day does not do the same amount of damage. N does not always equal 1. If you stayed out all night drinking, n=2. If you didn’t sleep well, n=1.5. If you were stressed all day at work, n=1.5. If you are overtraining, n=1.25.

So as you can see, if your x was 21,900 days, you could live to be 90 if you worked out and ate healthy every single day. But if you didn’t sleep well, overtrained, or any other number of things, you could manage to do more than a day’s worth of damage to your body in any one-day span. Let’s say that you struggle every other night sleeping for ten years. That would cost you 7.5 years of life in our model. You’d live to be 82.5.

Control what you can to maximize x and minimize n, because no one knows what their x is. Create an infinite series that you can live with, because like it or not, that’s what you’re doing.