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Wednesday, June 17, 2015

There are some amazing octogenarians out there

Some  know-it-all-officious-busybodies   medical progressive elite presume to know when various medical procedures should be limited on the basis of age. Some even presume to know how long someone will live as in recommendations regarding limiting of medical procedures for those deemed to have less than ten years life expectancy or using 75 as a cut off date for certain type of screening tests.My pathology professor in medical school was fond of saying when you tell someone how long he has to live they may piss on your grave.Spock's "live long and prosper" butts up against Dr.Zeke's proposed forgoing of preventive measures for those 75 and older, well at least for him, or so he claims now.

Two recent journal articles shed some physiological light on  some  folks in their 80s,folks about whom some of the progressive elite would desire to limit medical care.

Trine Karlsen et al described a remarkable 80 year old Norwegian.The authors believe that the subject of their study may have a world record for maximal oxygen uptake (VO2max). for his age 50,ml/kilo/min.Accordingly to the authors this value is compatible of a normal, active, non endurance trained 35 year old Norwegian man.(How to be 80 year old and have a V02max of a 35 year old, Case Reports in Medicine, Vol 2015, article id 909561). The "how " seems to be to have great genes and to be very physically active.

 To put V02 max  in some perspective; It is a measure of the highest rate at which oxygen can be utilized by the body during intense exercise.It is a function of how much blood the heart can deliver to the muscle ( cardiac output) and how  much oxygen the muscles can take up measured by the a-v oxygen difference.

It is generally believed to peak somewhere between age 25 and 35 and decreases afterwards. Various estimates of the rate of decline have been made. A stylized version is that the decrement is of the order of 5-10 % per decade until about age 70 and then V02 max declines more rapidly.For those who continue to do endurance exercise training the decrease is in the 5% per decade range.Some data indicate that endurance athletes' VO2 max actually decreases more per decade in absolute terms ( ml/minute/kilogram) but since they begin the decline with a higher absolute value their percentage decline is about half of that of the non trained healthy person. In that regard as in most things there are some conflicting data and considerable individual variation. Karlsen's subject has his 02 max measured at age45 so that the calculated decrease in his 02 max  from age 45 to age 80 was a remarkable 2.3 ml/min/kilo per decade while previous reports suggested the average decrease is 5.4 ml/min/kilo per decade. At age 25 he was measured at 75 ml,min/kilo.

World class endurance athletes typically have values in the 70s and 80's. The value of 90 is often quoted as the highest record, this in a 24 year old cross country skier while other publications quote the recording of 95 . The value of 17.5 ml/kilo/min ( 5 mets)  has has been labelled the aerobic frailty level, the value below which a person is by one  imprecise definition, frail, and would find the activities of every day life consuming such a high percentage of their O2 max that fatigue would greatly limit function.A value of 7 ml oxygen /kilo is said to be the lowest level compatible with life.Endurance exercise training programs typically increase 02 max by 10-15% ( with the occasional outlier of more than 30%) but those folks in the 70 plus range can thank their parents ( at least one of them) for their exercise capacity.The sled dogs who race have 02 max values in the range of 240!

Scott Trappe and co authors in an earlier article in the Journal of Applied Physiology ( see here) published detailed physiological data including results of muscle biopsies and muscle enzyme studies on 15 active healthy octogenarians (one actually was 91).Nine were long time endurance athletes and 6 were age matched healthy untrained men without serious medical conditions and who were fit enough to do the exercise testing. Not only had the athletic group been competitive cross country skiers in their youth, they had continued with vigorous programs and all had trained  on average 8 hours a week for the last fifty years. ( Fifty years is not a typo).The endurance athletes had 02 max values between 34 and 42 while the healthy non endurance folks had on average a 21.

And then there is Ed Whitlock.See here for details of his setting the marathon time record for a 82 year old human . He finished at 3:41:58 which is nine minutes 49 second per mile.Whitlock is also noted for being the only man to run a sub three hour marathon at age 70 or older.Estimating his V02 max using table 2.3 from Tim Noakes's Lore of Running ( which is derived from data of Davies and Thompson) gives a value of about 48 ml/kilo/min, which is close to Karlsen's subject's measured value..

addendum: 8/28/2015
Ed Whitlock is not the only 80something who ran a sub four hour marathon. Ed Benham ran a 3:48 marathon at age 82 and Harold Wilson did 3:58 in Boston at age 80. In the half marathon category Anne Garrett ran 2:13 at age 80 .

 Addendum: 1/19/16 Thee were four men 80 and over ( who made the six hour cutoff, in the 2016 Houston Marathon, the fastest of which ran a 4 hour 23 minute race. According to the guesstimate form the above quoted table from Noakes,he would have a 02 max of  39-40 , not too far from Karlsen's subject and way out of the curve for 80 years olds. 

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