How long will you live? Longevity and Life Expectancy Demystified (Part II)

It is only fitting that an article on longevity was too lengthy for a single post. This is Part II. Part I can be found here.

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In part one of this post we investigated the question "how long will you live?" by explaining life expectancy, life span, and the major changes of each over the past 100 years. In this post we look at the particular factors affecting your life expectancy.

It's a sad fact that we will all die, someday that is. The question is what is it that we will die from. If we know what will kill us we will have a pretty good idea when it is we will die. In the LifeTwo post "What Will Kill You" we covered the CDC data on what might kill you and when. For example, from 45 to 74 years old it's cancer, after 74 it's heart disease. Interestingly, from 25 to 85, your risk of death in a given year approximately doubles every decade you're alive--no wonder people in their 20's tend to feel invincible.

Such data is fine if you are looking at populations as a whole but not if you are interested to know how long YOU will live. Who cares what the average is if you are not average (and probably don't even know what that means anyway). Today, centenarians comprise the fastest-growing segment of the population, and their numbers have been doubling every six or years (in developed countries that is). How can you increase your chances of joining that exclusive club?

One thing you might read about is the now-famous lowered-body-temperature experiment with mice. In this study it was observed that mice whose bodies were manipulated to have a slightly lower body temperature ended up living longer than mice with a regular body temperature. Does this mean you should move to Alaska or take ice baths? Not really. These studies are in their very, very early stages and it is unknown what, if any, practical implication it will have on humans, let alone in our lifetimes.

Another widely reported study concerns a substance found in red wine — resveratrol that under specific lab conditions extended the life span of overfed, obese mice. Since the link between longevity and resveratrol was first observed there have been an explosion in sales of dietary supplements containing the ingredient. While promising, to date no human studies have shown much in the way of benefits.

As scientists grapple with aging and what might slow it down, a few areas are generating more heat than others including free radicals (highly active chemicals that cause damage to cells) and chronic inflammation.

One such area is "calorie reduction." "Scientists have discovered that they can extend life span in animals by restricting how much they eat: In rats and mice, a 30% reduction in caloric intake extends life span by a third." Once again, rats are not humans and more to the point, how many people want to undertake a lifelong starvation plan even if it did have the intended longevity benefits?

It's quite possible that the biggest factor in determining how long you'll live is out of your control, it's your genes. Centenarians were three times likelier to possess a gene variant called "CETP VV" compared with a control group representative of the general population. CETP VV has the added benefit of delaying cognitive decline.

"[Scientists] have shown that the same gene variant that helps people live to exceptional ages has the added benefit of helping them think clearly for most of their long lives. It's possible that CETP VV's cognitive effect is to protect against the development of Alzheimer's disease. In studying these centenarians, we hope to learn why they're able to resist diseases that affect the general population at a much younger age. This knowledge should greatly aid our efforts to prevent or delay the onset of age-related diseases."

Everything we've listed in terms of longevity is in it's early research stage. So what might one do today to extend one's life? One word, lifestyle. And to help you, we've got the the top ten tips for healthy aging. You won't see any surprises but it makes a great checklist if you are really serious about living as long as possible.