Compression of Morbidity Through Physical Activity

Compression of morbidity is a hypothesis suggesting that advances in medical science are causing, or will cause, a compression of the terminal period of frailty, illness, and disability at the end of life, squeezing it into an ever-shorter fraction of the overall human life span. In colloquial use compression of morbidity is often spoken of as a practical goal by medical researchers who do not wish to talk openly about extending human life for political or funding reasons.

There is data to support the existence of compression of morbidity with respect to the effects of lifestyle choices on longevity, such as exercise. When it comes to advances in medical science, however, it seems unlikely that gains in life expectancy will forever lag behind gains in health. Consider aging in terms of accumulated damage, for example: if we find ways to repair that damage, then the overall life expectancy will increase, just as it does for any complex machine that is better maintained.

In any case, here is an example of present data supporting a compression of morbidity through increased physical activity:

"Active aging" connotes a radically nontraditional paradigm of aging which posits possible improvement in health despite increasing longevity. The new paradigm is based upon postponing functional declines more than mortality declines and compressing morbidity into a shorter period later in life. This paradigm (Compression of Morbidity) contrasts with the old, where increasing longevity inevitably leads to increasing morbidity.

We have focused our research on controlled longitudinal studies of aging. The Runners and Community Controls study began at age 58 in 1984 and the Health Risk Cohorts study at age 70 in 1986. We noted that disability was postponed by 14 to 16 years in vigorous exercisers compared with controls and postponed by 10 years in low-risk cohorts compared with higher risk. Mortality was also postponed, but too few persons had died for valid comparison of mortality and morbidity. With the new data presented here, age at death at 30% mortality is postponed by 7 years in Runners and age at death at 50% (median) mortality by 3.3 years compared to controls. Postponement of disability is more than double that of mortality in both studies. These differences increase over time, occur in all subgroups, and persist after statistical adjustment.



Compression of morbidity and the 'reliability' theory of aging are IMHO closely related to a communications field concept: error correction coding.

In error correction, EC for short, the idea is that if you send data over a noisy channel, there is a chance that some of your data will be received with errors caused by the noise. By adding redundant data, for example by sending each piece of data three times, you can reduce the odds that an error will be received. If you increase the noise level, the number of errors will be increased, and more redundant data will be required to make errors less likely.

If your noisy channel is limited, it turns out that there's a trade off between the noise level and the data rate you can get through it. If the noise level is very high, you have to send a lot of redundant data to get through even a single bit; if the noise level is very low, you may be able to get a lot of bits through the channel quickly.

Consider a channel that sends through a fixed number of bits per second with error correction. The noise level starts out low; the chance of errors is similarly low. Now over time, the noise level begins to increase. The chance of error remains low for a while, but then begins to rise. Eventually the noise level reaches the point where the chance of error is so high that no data can be received at all. This signal level, where no communication is possible, is called the Shannon Limit, and it is absolute.

That point, where the error swamps any possible error correction, is similar to the 'compression of morbidity' limit. The number of errors simply exceeds the ability to the repair system - any repair system - to correct.

To extend the analogy further, interventions like cholesterol lowering drugs and cancer treatments can be seen as nothing more than an additional layer of error correction, performed by the outside world, to handle errors that the body was unable to correct. In short, as medical treatment gets better, it is merely covering up gaps in the already outstanding error correction of the body.

From this standpoint, it's obvious why medical treatment hasn't increased the maximum lifespan by a meaningful amount: because it's just adding more error correction, and not reducing the cause of the errors. As long as the damage continues to accumulate, as long as the noise level rises, eventually a point will be reached where no level of error correction can recover the original signal, and the person will die.

This analogy, however flawed it may be, is in my opinion a powerful argument for damage correction and reversal treatments, as opposed to post-damage or damage slowing treatments. It is the primary reason why I tend to view the fightaging/DeGrey approach as holding more long term potential than current conventional approaches.

Posted by: Dennis Towne at November 6th, 2012 4:06 PM

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