10 Interesting Predictors of Longevity

http://www.marksdailyapple.com/

This isn’t a Homeric epic. There are no oracles laying out our destiny and predicting our inevitable demise. But even if we can’t know the precise date of our death, we can use certain biomarkers, measurements, and characteristics to make predictions—with a reasonable amount of accuracy—about a person’s propensity to kick the bucket.

As is the case with any observational data, these predictors may not be malleable. And if they are malleable, actively changing them won’t necessarily confer the longevity they’re associated with. Getting plastic surgery to appear younger probably won’t make you live any longer. But they do tell a story. They suggest the qualities, activities, behaviors, and exercise patterns that may, if maintained, lead to a better, longer life. At the very worst, walking a bit more briskly and gaining some lean muscle won’t hurt you, and it will very likely help you.

So let’s take a look at ten of the most interesting predictors of longevity:

1. Handgrip strength.

You know your grandpa with the vice grip for a handshake? Or that old lady who simply would not give up her hold on those plush towels last Black Friday at the Walmart despite you yanking her around like a rag doll? They’ll probably live a long time.

In middle-aged and elderly people, grip strength consistently predicts mortality risk from all causes. It’s even better than blood pressure. In older disabled women, grip strength predicts all-cause mortality, even when controlling for disease status, inflammatory load, depression, nutritional status, and inactivity. Poor grip strength is even an independent risk factor for type 2 diabetes across all ethnicities.

2. Walking speed.

A few years ago, a study of over 7000 male and 31,000 female recreational walkers found that walking intensity predicted mortality risk. Those who walked the fastest tended to die the least. Now, don’t think you can consciously speed walk your way past a hundred. Researchers in the study were looking at the natural walking speed of frequent walkers. What the study tracked and linked to lifespan was the natural walking speed of the participants. They had no idea they’d be graded.

A more recent study found that rapid declines in walking speed also predicted death. Some clinicians find so much value in walking speed that they even use it as a “sixth vital sign.”

3. Facial appearance.

Several studies indicate that the perceived “age of the face” is a better predictor of mortality risk than objective health markers, actual age, or cognitive function. More objective measurements of aesthetic age, like wrinkling in areas unexposed to the sun, also predict longevity.

4. Subjective opinion of one’s quality of life.

If you’re happy with your physical and psychological health, social relationships, and your immediate environment, you may live longer. Having a poor opinion of your current lot in life may have the opposite effect. Even when those subjective opinions are compared to objective measurements of your health, your relationships, and your environment, subjective outlook is a better predictor of lifespan.

5. Muscle.

I’ve always said that lean muscle mass is a metabolic reservoir for healthy aging. Skeletal muscle produces important proteins and metabolites that regulate recovery from trauma and injury. The more you have, the better you’ll recover from surgeries, burns, falls, breaks, punctures, and damage. The more muscle you start with, the more you can spare to wasting and the better you’ll bounce back from bed rest and other forms of forced inactivity. Expression of klotho, the “longevity protein,” is even strongly dependent on the strength of one’s skeletal muscle.

6. Life purpose.

The popular notion that being driven to achieve your goals increases wear and tear on the body and destroys your health seems right. You’re sacrificing sleep for work, neglecting loved ones, choosing work over exercise, eating junk food instead of cooking. What does the evidence actually say? It turns out that having something to live for helps you live longer with a lower disease burden. Life purpose predicts allostatic load, another way of saying “age-related wear and tear.”

This was a little surprising. We often think of the hard-working entrepreneur burning the candle at both ends, falling apart at the seams, health suffering just to pursue and achieve the goals. But the actual evidence refutes this.

7. Intelligence.

Intelligent people live longer. Across any and all causes of mortality, having a higher IQ confers protection.

Some point to the quicker reaction times that also accompany higher IQs. If you’re smarter, you’ll probably have an extra fraction of a second to swerve out of the big rig’s path and avoid a fatal collision. This is certainly part of it, but a faster reaction time can’t explain the protection intelligence confers against all-cause mortality.

Others attribute the all-encompassing protection to the intelligent decisions, healthy behaviors, and prudent practices smart people make and follow (PDF). The smarter you are, the less likely you are to smoke, not exercise, or think fast food is okay to eat for dinner every day of the week.

8. White blood cell count.

White blood cells, or leukocytes, are the primary agents of our immune system. They battle pathogens, infections, and foreign invaders. Many diseases are associated with white blood cell deficiencies, so it seems like healthier, longer-lived people would have high leukocyte counts. Right?

No. Actually, leukocyte counts on the lower end of normal predict longevity. That only seems to be true in healthy men and women. It’s unlikely to persist in unhealthy or immunocompromised populations who actually need the white blood cells to stave off causes of. In the healthy folks, a low-normal WBC count indicates a low disease burden.

9. Autophagy.

Autophagy is cellular maintenance. It’s how our cells recycle waste material, eliminate inefficiencies, and repair themselves. It’s required to maintain muscle mass as we age, and inhibiting it induces age-related atrophy of adult skeletal muscle. It reduces the negative effects of aging and reduces the incidence and progression of aging-related diseases. In fact, researchers have determined that autophagy is the essential aspect of the anti-aging mechanism of fasting. “Aging” only occurs when cellular autophagy fails, or reduces. People who live past 100 have higher levels of the primary autophagy biomarker, meaning their cells are maintaining themselves longer and retarding the aging process.

This is something you can directly control. Fasting, ketosis, caloric restriction, exercise, and dietary polyphenols all trigger autophagy, and they’re all likely to improve longevity.

10. How much broccoli and Indian food you eat.

I’m kind of kidding, but not really. Maybe the most important anti-aging pathway in the body is Nrf2. Activating Nrf2 unleashes many antioxidant pathways, increases glutathione, and has been shown to trigger the “anti-aging phenotype” in animal studies. Foods in the brassica family, which includes broccoli, kale, cabbage, cauliflower, and Brussels sprouts, all contain sulforaphane, a potent Nrf2 activator. Another Nrf2 activator is curcumin, found in turmeric, the primary spice in Indian curries.

If I’m being safe, these are merely descriptive. People who already have these attributes, biomarkers, and tendencies are more likely to live longer than those who do not. But if I’m engaging in educated speculation, many are also prescriptive. Lifting weights, going for walks, finding a life purpose, improving your day-to-day quality of life, eating more antioxidant-rich food (including broccoli and turmeric), triggering autophagy through fasting or occasional bouts of caloric restriction and ketosis—these are all good, healthy practices that should pay off.

What do you think, folks? Can you think of any interesting longevity predictors not mentioned today? Which of these are you already implementing?

Thanks for reading. Take care.

Filed under: Fitness