a special program of the National Emergency Medicine Association (NEMA)
Transcripts: 509-1 to 509-5
Week: 509.1 Guest: Leonard Hayflick, M.D. Topic: Aging - Part One Host: Richard Roeder Producer: Ed Graham
NEMA: This is a five part series on aging and what can and can't be done about it. My guest is Dr. Leonard Hayflick, author of How and Why We Age, published by Ballantine Books.
NEMA: Dr. Hayflick, first let's sort of lay a little background with what may seem like an obvious question but maybe it's not so obvious. What is aging?
HAYFLICK: Aging can be defined in many different ways. In fact, one of the chief problems in the field of biogerontology as we call the biological aspects of aging is indeed coming up with a definition that will satisfy most or all workers in this field and in fact that has not been achieved. It's one of the few areas of science where we cannot define the field in which we work to the satisfaction of all of the workers in the field but let me give you a few definitions that might help to understand what we are dealing with and that is the decrements or the physiological losses that occur in animals and let's say in humans after they reach sexual maturation. Those changes that occur after that period of time which is not a specific point in time but a range of, in the case of humans, possibly years, those changes are called age changes and they're usually losses in physiological capacity.
NEMA: You talk about and interrelate three different words - longevity, aging and death - and even though they all interact in some obvious ways you also make the distinction that they're not all the same thing.
HAYFLICK: No they're not the same thing. Death I think is obvious to all of us so that doesn't need definition but longevity is determined, many of us think and I'm one of the advocates of this position, longevity is determined indirectly genetically as I indicated in response to the earlier question at sexual maturation. Physiological decline begins to occur. The important point to be made is that the goal of any animal species in cold biological terms is to maintain that species for an indefinite period of time. In order for that to occur, it's clear that the individual members of the species must live long enough to procreate and raise offspring to independence. For humans that would be roughly the age of 30. So that is the time when decrements begin to occur because natural selection has not provided us with a peak capacity of our physiological background after sexual maturation is reached. Now having said that, the best way for an animal to reach sexual maturation, to best guarantee that occurring is to build in redundancy in the major physiological needs so that when you and I reach sexual maturation or age 20 or 30, we're at our peak of physiological capacity because we have been through natural selection, selected to have more capacity than we actually need in order to guarantee our survival to that age. Now once having reached the age of 25 or 30, we now have all of this excess capacity and it then begins to decline because natural selection has not perfected our physiology to exceed that point.
NEMA: Join me for part two on aging with Dr. Leonard Hayflick.
Week: 509.2 Guest: Leonard Hayflick, M.D. Topic: Aging - Part Two Host: Richard Roeder Producer: Ed Graham
NEMA: This is part two in a five part series on aging with Dr. Leonard Hayflick, author of How and Why We Age, published by Ballantine Books. I asked Dr. Hayflick what happens to humans between age 30 and death.
HAYFLICK: During that period of time, the changes that occur, the losses in physiological capacity, as I mentioned earlier are age changes, i.e., in the terms of a physicist, increasing entropy or increasing disorder in formerly orderly molecules so that aging must be distinguished from longevity determination and clearly from death.
NEMA: What factors do you believe are the most crucial in terms of controlling biological age or the deterioration of biological age?
HAYFLICK: Perhaps one of the most important aspects of maintaining molecular integrity are the repair processes that we have within our bodies of which there are literally thousands. Even at the cellular level, we find repair processes occurring even in the DNA which determines our genetic heritage. There are literally thousands of these errors occurring in our cells almost hourly in each cell and those errors must be corrected. The efficiency of these correction systems or repair systems, if you will, is not 100% after sexual maturation is reached so that the repair processes themselves become faulty and the aging process continues. There are many other potential answers to that question. This perhaps is one of the more important ones.
NEMA: One thing you make reference to in the book and it's certainly a word that is very commonly heard nowadays in the media and it's certainly heard in health papers and so forth - and that is oxidation and the sale of anti-oxidant vitamins is at an all time high right now. How major a role do you believe what is called oxidation and the subsequent free radicals actually play in the aging process?
HAYFLICK: There's a great deal of evidence that supports the contention that free radical production which is, for those who may not know, the production of very fast reacting oxygen, parts of oxygen molecules that react with other chemicals in a cell very quickly and can produce damage unless those oxygen radicals are tied up and they can be tied up by anti-oxidants as you've indicated, however, there is a controversy about the interpretation of this information and that is that the use of anti-oxidants in experimental animals although it has shown an increase in life expectation has not shown an increase, at least convincingly, in life span and those two concepts must be carefully distinguished. Life span is a maximum number of years that an animal can live and life expectation is, as the name implies, the anticipated number of years or months that an animal can live given a particular starting age so that what anti-oxidants have been shown to do in a laboratory is to increase life expectation.
NEMA: Join me for part three on aging with Dr. Leonard Hayflick.
Week: 509.3 Guest: Leonard Hayflick, M.D. Topic: Aging - Part Three Host: Richard Roeder Producer: Ed Graham
NEMA: This is part three in a five part series on the biology of aging with Dr. Leonard Hayflick, author of How and Why We Age, published by Ballantine Books. I asked Dr. Hayflick about the role of oxidation and free radicals in aging and life expectancy.
HAYFLICK: What anti-oxidants have been shown to do in the laboratory is to increase life expectation, however, that does not prove that the role of free radicals is directly associated with the aging process. To give you an extreme example of the point that I want to make, let's suppose that we could legislate the internal combustion engine off of our streets beginning tomorrow morning. That would in fact increase life expectation on the average in this country by about three to six months. No one, however, would argue that the internal combustion engine causes aging in this country and likewise the fact that anti-oxidants fed to animals increases their life expectation. It does not therefore result in the conclusion that free radicals cause the aging process. The information that we have about free radicals is only indirect. We have no direct evidence of its relationship to the normal aging process.
NEMA: You talk in the book about some very surprising things. I think a lot of people would be surprised to know what you say would happen if we obliterated cancer from the face of the earth or we obliterated heart attack and heart disease from the face of the earth. A lot of people I think would be surprised to know how much or how little that would really increase the average life span. Talk about that a little bit.
HAYFLICK: Yes. You're correct in that interpretation. Every time I present a public lecture on this issue and give that data, you do have a surprised audience. If cancer were cured tomorrow morning, the increase in average life expectation would be about two and a half or three years for virtually all ages. The leading cause of death in this country and in most developed countries of course is cardio-vascular diseases. If they were resolved - and stroke I should say, vascular diseases in general - the increase in life expectation would be about 12 years so that the rest of the causes of death as written on death certificates and I stress that clause, as written on death certificates, if they were resolved, that is infectious diseases, perhaps tuberculosis, accidents, etc., those other causes of death would not result in an increase in life expectation if they were resolved to the extent that the cure of cancer and cardio-vascular disease would so we can ignore those. So it follows therefore that if the National Institutes of Health were successful in all of their goals and we found ourselves tomorrow morning to be free of the leading causes of death in this country, we would have an increase of, let us say, 13, 14, 15 years of life expectation even if that could be questioned by demographers or actuaries and indeed it has been. There would be a measurable increase, even if it was 15 or 20 years. It is still finite and that's the point that I'd like to make, that once having resolved these causes of death written on death certificates, we would not become immortal. That's the take-home message.
NEMA: Join me for part four on aging with Dr. Leonard Hayflick.
Week: 509.4 Guest: Leonard Hayflick, M.D. Topic: Aging - Part Four Host: Richard Roeder Producer: Ed Graham
NEMA: This is part four in a five part series on aging with Dr. Leonard Hayflick, author of How and Why We Age, published by Ballantine Books. I asked Dr. Hayflick what would happen to human life expectation if science cured all of the diseases written on death certificates.
HAYFLICK: People would die. The question is what would they die from? And the answer is the increase in loss of vital physiological capacity in some essential organ. In other words, one could write "loss of physiological capacity in the kidney or in the lung" or in some other vital organ that would reach a point which would not be compatible with life and hence that would be written on the death certificate.
NEMA: Another interesting thing that you talked about in the book that goes back and forth again for either political or medical reasons, I'm not sure which, maybe you could tell me, men do get diseases at earlier ages and have a higher rate of mortality from them, do they not?
HAYFLICK: Yes. Perhaps not at an earlier age but certainly the implication of that is true and that is that for virtually every disease that does not affect obviously the female urogenital tract, for example, the susceptibility of males is greater than females and the pathology is usually more severe so that males are certainly not the stronger sex. Females in this context are clearly the stronger sex. There are some number of political and economic cross currents that run through this and also the distinction that must be made between diseases and aging and this is a very crucial distinction. I don't believe that aging is a disease. Unfortunately most of the public somehow equates the normal aging process with disease. It's not a disease because unlike a disease, aging affects everyone. There's no disease that affects everyone. Also aging occurs only very late in life or at least it begins at a particular point in life and continues from that point on. There's no disease that follows that kind of temporal relationship as perfectly as aging does. And finally aging crosses species barriers, if you will, i.e., aging occurs in virtually every animal that we choose to try to find it appearing in and that is not true of any particular disease so having made that critical distinction, we must then appreciate that fact that what we associate with aging as disease is really an increase in vulnerability as a result of the normal aging process to disease or to what we ultimately find written on a death certificate. Even to the extent that someone might, at the age of 80, be killed by a bus or car accident, one could argue I think effectively that that death was not caused by the bus or the car but only indirectly because the aged individual could not react as quickly when he or she spotted the vehicle or couldn't run as fast, leap as high, etc., so that the normal aging process really did them in and not the meeting of their body with the bus or car.
NEMA: Maybe the closest thing we have to natural selection left in our structure.
HAYFLICK: Yes, precisely.
NEMA: Join me for part five on aging with Dr. Leonard Hayflick.
Week: 509.5 Guest: Leonard Hayflick, M.D. Topic: Aging - Part Five Host: Richard Roeder Producer: Ed Graham
NEMA: This is part five in a five part series on aging with Dr. Leonard Hayflick, author of How and Why We Age, a book that explores the science and myths of health, disease and ultimate life expectation.
NEMA: How much do diet and exercise, for example, contribute to a person's ability to extend their life?
HAYFLICK: Diet and exercise and any other common activity that people believe will retard the aging process is nonsense. We know of nothing with the possibility of one exception that will tamper or interfere with the inexorability of the aging process. What you do want to do when you exercise and care for yourself nutritionally and otherwise is to prevent, delay or decrease the effect of disease, in particular cancer and cardio-vascular disease, and as I've indicated earlier by being successful you can delay or prevent the occurrence of these two major causes of death and as a consequence of that, your life expectation will be increased but your life span will not be increased. The maximum human life span which is roughly in the range of 120 years will not be exceeded if indeed you're a successful exerciser and do everything else perfectly so that there is no way we're going to escape. This unfortunately is not accepted by a substantial portion of civilization in this country for reasons that are almost beyond a biologist's ability to understand when the evidence is about as ironclad as it can be. We know of no one who has ever escaped alive in the sense that they've lived for more than 120 or 125 years and why any of us should be an exception is beyond my understanding and the understanding of virtually every other scientist in this field.
NEMA: So clearly what you're saying is humans individually may have the opportunity to avoid the shortening of their own natural life but they're not going to exceed the expected life span of 120 years, not expected but the maximum life span ......
HAYFLICK: That's exactly right. What we want to do, I think, if we have any kind of realistic role here is to maintain our physical and cognitive abilities in as perfect a condition as we can for as long a period a time as we can with the certainty that there is a limit and the limit is about 120 years. In fact, I can't think of a scenario, and I would challenge anyone else to come up with a scenario, that would benefit either society in general or you as an individual under circumstances where you would be able to manipulate your aging process by either eliminating it entirely so that you would be immortal or even if you had the capacity to slow down your aging process. This is a very complex area and is colored by the likelihood that not everyone would choose to use the magic white pill that would accomplish this result. We would find all kinds of bizarre asynchronous problems within families, for example, or how we relate to each other outside of family relationships.