SAGE KE Bulletin Board

1000-year lifespans are closer than they seem: a reply to Kirkwood

16 September 2005

Aubrey D.N.J. de Grey

Nature have somehow found themselves unable to find space to publish the following, so I thought I should share it with the community in another way.


Sir—In your August 18th issue, Kirkwood [1] describes my recent claim [2] that the first person to live to 1000 could be 60 already as "laughable" and "arrant nonsense." I derive it as follows:

- At least a few hundred of today's 60-year-olds will live to 110, barring a rise in age-specific mortality rates [3]. I will call these people "the 1945 elite", after their year of birth.

- Since "the older you get, the healthier you've been" [4], most of the 1945 elite will still be as robust as typical 60-year-olds when they are 85, i.e. in 2030.

- By 2030 we may well have developed regenerative medical technologies that can double the remaining lifespans of such people, from 25 years to 50. These therapies will repair or obviate the various types of accumulating molecular and cellular damage that are at the root of aging – not perfectly, but comprehensively enough to maintain the 1945 elite for the next 25 years in no more aged a physiological state than they were in when the treatments were begun [5]. Thus, if these therapies are developed and made widely available, in 2055 most of the 1945 elite will still physiologically resemble today's typical 60-year-olds.

- Other things being equal, the 1945 elite will then age much as now, albeit at a 25-year greater chronological age. But other things will not be equal, because in those 25 years the therapies first applied to the 1945 elite at age 85 will have been improved in comprehensiveness – and this improvement, if technological (including medical) past precedent is any guide, may be very rapid. The 1945 elite will therefore probably never return to the state of disrepair of a typical 60-year old, but will instead continue to enjoy progressively more thorough rejuvenation as these therapies continue to be refined faster than their remaining imperfections are allowing aging to proceed [6].

- Thus, if the above advances occur on the schedule just described, the 1945 elite will mostly avoid death from old age at any age, which means that about 1/3 of them will have four-digit lifespans [7]. While the probability of that “if�? is arguable, one would be brave to put it at under 1%, which is what is needed in order to expect no one currently 60 to reach 1000.

Arguable? Certainly. Laughable? MIT Technology Review's $20,000 "SENS Challenge" says not [8]. The longer that prize goes unclaimed, the hollower the skeptics’ ex cathedra scoffing will ring.

Aubrey D.N.J. de Grey

Department of Genetics, University of Cambridge, Downing Street, Cambridge CB2 3EH, UK


1. Kirkwood, T. Nature 436, 915-916 (2005).

2. de Grey, A.D.N.J. (2005).

3. Coles, L.S. Rejuv. Res. 8, 69-71 (2005).

4. Hitt, R., Young-Xu, Y., Silver, M. & Perls, T.H. Lancet 354, 652 (1999).

5. de Grey, A.D.N.J. et al. Ann. N.Y. Acad. Sci. 959, 452-462 (2002).

6. de Grey, A.D.N.J. PLoS Biol. 2, 723-726 (2004).

7. Comfort, A.J. The Process of Ageing (Signet, New York, 1964).

8. Pontin, J. (2005)

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