BY DR. DANIEL L.JOHNSON

Our Life Goal:Senescence!

Previous columns: www.tinviirl.com/ wave action, and we want to understanddrdanscolumns the tide.

Americans have long acted as thoughdeath is something that happens to

other people. My own patients are oftenshocked to discover that there are somethings we can't fix with pills or surgery."Should I see a better doctor?" they hint.

The answer is, "Yes, there are manybetter doctors; yet some things cannotbe taken away." Many of these we do toourselves, yet no matter how healthy weare, if we're lucky, we become old - and,at the end, decrepit.

More than one person has said to me,"Doc, getting old takes more couragethan anything I've ever done."

Years ago, I had a chat with JohnMiller, then at 96 the oldest activecommercially-rated pilot in the coun-try. When asked how aging had affectedhim, he said, "I've had to adjust. Boy,have I had to adjust!"

How are you adjusting to your ownaging?

The losses of aging are actually slowand subtle until the very end. Lack ofpractice is, I believe, more debilitating toskill and judgment than aging itself (getout and fly!). There are four things thaterode performance:

• disease• injury• skipping practice• senescence.Today, we're going to talk mainly about

senescence. I have to say that the litera-ture of medicine and physiology is notof great help here. This is because sciencespends most of its effort on the minutiaeof the seabed and the hydrodynamics of

Soaring • March 20Id

Deciduous TreesTrees lose their leaves each autumn.

As a child, I thought that the leaves diedand then were blown off branches bythe wind. It puzzled me that the whiteoaks and burr oaks of central Minnesotakept their brown leaves all winter (whichseemed inconsiderate and ugly) whilethe birches and maples lost theirs beforethe snow fell, so that we could get thelawn raked.

The truth is that conifers also lose a fullyear's growth of needles each fall - buttheir brown needles are two years old,and this loss is obscured by retaining thepresent year's green new growth (exceptfor the tamarack, in swamps, which losetheir needles annually).

Decades ago, a colleague came late torhospital rounds on a still, cloudy Sat-urday, and said, "After breakfast I sat inmy living room for a couple of hours andread a book. When I sat down, the mapletree in the yard was full of orange leaves.About 9 o'clock, leaves started to drop asif it were snowing, and by 11, the limbswere bare and there was a big circle ofleaves at the foot."

This is a wonderful example of leafsenescence: a precisely regulated andtimed process that shears the leaf orneedle from the branch, allowing gravityto do its work.

The cellular biochemistry and genet-ics of this process has been pretty wellworked out. An analogous process is thatevery hair growing from us is, on a cycle,ejected from its follicle and then newgrowth begins. This cycle is what limits

From full foliage to none, leaf senescence is regu-lated and timed.

the length of our tresses and our beards.Everyone's cycle has its own duration;everyone's maximum length is unique.

Senescence of the body in general isnot quite like this, yet is just as real and

just as inevitable. I've been consciouslywatching people age all my life, and asa physician, for 45 years. Eventually itbecame clear to me that even healthypeople begin at some point to fail, andif they remain healthy, it seems to takeabout 3 years from first generalizedfrailty to death.

Research on human and animal aginghas shown that there are many waysto accelerate this (mostly, joyfully self-inflicted), and no way to prevent ordelay it. Through science, our impotenceagainst senescence has become sophisti-cated and nuanced.

Before senescent, debilitating decrep-itude begins, aging changes bring lossof ability and resilience. It is sometimesnot clear when loss is from disease andwhen from aging. If there's no remedy,the distinction may seem academic,though we always feel like we're stand-ing on firmer ground if we have a well-reasoned explanation, whether factualor fictitious.

What I see is that, from one individualto another, the senescence of the vari-

ous body organs is not synchronous. Insome, it's first the lungs, in others, thebrain, and in still others, the heart.

Looking in the mirror, each of us cansee our skin change. For nearly every-one, senescence is combined with illnessand injury, exacerbating the asymmetryof loss.

The Nature of SenescenceAll sorts of bad things happen - es-

sentially nothing works well. Simplyarising from bed and toddling off to thebathroom to pee at 3 am may take theathletic talent that a backward somer-sault once did.

In my experience, the most annoy-ing things are that one's skin becomespaper-thin and fragile; keeping one'sbalance in ordinary situations becomessuspenseful; and the brain slows downin every way.

Our gut doesn't work as well. Foodis incompletely digested, which colonicbacteria turn into aromatic hydrocar-bons, making us all into old farts. Thecolon itself gets sluggish, often requiring

medical assistance.Our parts that were elastic get stiff,

and firm parts get floppy. Resilient car-tilage becomes brittle and fractures.Teeth lose their moorings.

This general deterioration makes usmore susceptible to disease, and if we'relucky, a serious and painless disease willthen mercifully slay us. Such as pneumo-nia, the old man's friend, against whichwe vaccinate mindlessly to improve ourpublic-health statistics.

Aging in GeneralPrior to these years of rapid final se-

nescent impairment, we experience along, almost insensible, slow diminutionof powers that does not incapacitate, butto which we must adjust if we are to besafe and are to show good judgment.

This is judgment: to realistically as-sess ourselves, test our limits safely, andadapt to these. My view is that mostskill loss is not due to aging, but to lackof repeated practice. Lack of practicehas two bad outcomes: the obvious oneis erosion (or evaporation) of skill. The

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hidden one is that we do not probe anddiscover our limits.

Continually Re-trainMy personal universe is small, but I

think it's representative. Pilots I knowdon't spend much time in systematicpractice, with or without an instructor.I'd much rather ride with a medicallyimpaired pilot who's been practicingregularly than a healthy one who's com-placent about his skills.

Delaying SenescenceEvery so often someone well-read on

the Internet confidently tells me thatmedical research is soon going to solvethe problem of aging, extending lite-spans to 130 years or more.

One bad side effect of this would befreezing the seniority queue at work.Another would be extending the physi-cal health of the decrepit 85-year-old by45 years.

You might recall the medieval storyof the young man who sold his soul tothe devil for the promise that he wouldnever die. He became old and infirm,and then discovered that he could'notdie.

The medical discoveries of the pasthalf-century have indeed extended theadult lifespan, but the increase has beenthe same devil's bargain: the lives of el-derly people are prolonged; healthy liteis not.

No means of delaying senescence hasbeen found.

Getting Old FasterOn the other hand, it's easy to age

prematurely. I noticed when I beganpractice that I guessed the ages of some

women patients as being ten years olderthan they were - and this was as trueof the 20-year-old as the 50-year-old!These were the smokers!

Research in the 1970s showed thatsmoking causes premature skin wrin-kling and impairs fibroblast function(the cells that repair injured tissue).Research within the last decade hasidentified the aging proteins inducedby smoking.

The Western diet seems not to pro-mote aging so much as it causes disease:diabetes, heart disease, and cancer.

Organic hydrocarbons trom crude oilderivatives impair immune tunction,and I am confident that there's a largecollection of other harmtul substancesalready known to biological science ofwhich I'm unaware.

Some people become senescent laterthan others from genetic differences,possibly induced by generations of harshenvironmental conditions. More than60 years ago, it was shown that whenlaboratory rats were raised with scantfood in cold conditions, average lite-spans increased.

Yet, for the most part, it seems thatpeople who age better have generallydone less to hasten aging than theirpeers. The most important thing is to eatfruit and vegetables instead of sugar andfat. Next most important is not to inhalesmoke; then, regular exercise. Then, be-ing loved and being part of social groups.

When It's Time to QuitMy experience is that most people

recognize loss of ability (sometimes alltoo well, mistaking lack ot practice foraging losses), and adapt.

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Those who do not are exceptional -yet cause a great deal of anxiety for therest of us.

First, the people who never had verygood judgment don't improve when theright stuff goes away. Sometimes theycheerfully admit to having poor judg-ment - and this insight does not maketheir decisions better.

Second, some people who've beenjudicious and wise lose it. The problemhere is that we trust them, and their lossot judgment is invisible. A creativelybrilliant person morphs into unpredict-ability; the attorney begins to give pooradvice; the accountant forgets nuancesof tax law. A respected CEO leads hiscompany into catastrophe before anyonerealizes the train is going off the rails.These things have happened many times.

This is a great challenge: to admit toourselves that we aren't what we were;to recognize others getting simpler orless analytical - and (kindly if possible)disconnect leaders from responsibilitywhen the problem is discovered.

Speaking of Quitting...This is my 60th monthly essay - five

years.This seems like a nice, round num-ber at which to draw this tradition to aclose, at least for duration of this soaringseason. It has been a wonderful experi-ence, and I use the columns-trove ottenin my practice as educational material.

Every month I write a term paper onsomething about which I want to knowmore, that might be interesting to soar-ing humans, and is at least vaguely re-lated to aviation physiology.

The problem is that this vacuums upabout a week of scarce spare time eachmonth, eating up time that might go toother priorities, including studying myown soaring topics - such as learningto use the new panel instruments, oranalyzing flights, or practicing on thesimulator.

I'm told that I seem humble andhonest, which is genuinely an aim. Ialso try to be witty, but most people lo-cally seem not to notice. Perhaps youteel that way, too. In any case, it's beena pleasant, life-enriching run. I'll soontake a leave of absence that may or maynot end next fall.

Happy flying! drdan^wwt.net

Soaring • March 2016 • www.ssa.org