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Sunday, March 18, 2018

Mitochondrial function in octogenarian endurance athletes

Scott Trappe from Ball State University and colleagues from the Karolinska Institute studied 9 lifelong endurance athletes 80 years of age or older  with 6 healthy 80 years olds who did no regular exercise. Aerobic capacity and muscles biopsies -done to measure levels of oxidative enzymes- were compared between the two groups.

The muscle biopsies showed high levels of citrate synthase and beta hydoxyacyl-Co A dehydrogenase in the athletes said to reflect the oxidative potential of the mitochondria. These values were similar to those from untrained young subjects.Quoting the authors: " It is important to note that mitochondrial function normally declines with age and this decline does not appear to be reversible with endurance training in sedentary adults greater than 80 yr old or very old animals." This implies that one has to start earlier and maintain some level of regular aerobic exercise to keep your muscle mitochondrial young.

I have commented  before on the impressive aerobic capacity of select elite older athletes.see here.Trappe'sathletes had measured maximal oxygen uptakes of 38 +/- 1 while the healthy controls averaged 21+/1/ .(O2 max in the range seen in the athletes would roughly correlate to the levels seen in someone able to run a 26.2 marathon in 4 to 4/1/4 hours,A 21 02 Max should allow someone to finish stage 1 of the Bruce treadmill protocol and into the second stage but likely not to completion of Stage 2.)Stage 1 Bruce protocol corresponds to 5 Mets roughly equivalent to walking a 15-16 minute mile and  to be able to finish Stage 2 corresponds to 7 Mets roughly equivalent to jogging a 15 minute mile.

Trappe's article is entitled "New Records" but as amazing as these guys were aerobic wise an Englishman transposed to Canada is one rung above on the aerobic scale. Ed Whitlock at age 80 finished the Toronto Marathon in 3 hours and 15 minutes.Using table 2.3 from Tim Noakes's book ,4 th edition The Lore of Running this time would correspond to an estimated  V02 Max of 50-55! See end note 1

1) Trappe S Et al New Records in aerobic power among octogenarian lifelong endurance athletes.J. Applied Physiology 114.3-10 2013.

End note 1.Rather than considering estimated 02 max from a table we can see actual measured values done on Ed Whitlock on two occasions. From the excellent blog entitled "Canute's efficient Running Site" we learn that just before his 70th birthday Whitlock's measured V02 max was 52.8 and at age 81 it was measured at a physiology lab at McGill to be 54!. Assuming that the difference between 52.8 and 54 was just normal test-retest variation, Whitlock seemed to loose no aerobic capacity over a ten year period. Conventional   wisdom and more than a little data indicate that the 70-80 decade is typically a time period in which there is an accelerated decline in 02 max,perhaps twice that of the 10 % per decade decline than is widely quoted. Whitlock did not get the memo.The VDOTvalues that are referenced on Canute's website and found in detail on Jack Daniel's VDOT Running Calculation web site appear to give more realistic estimates of running times that those that I have been using for comparison with exercise testing comparison that those  found on Noake's table.

addendum: End note 1 was completely redone after discovering Canute's web site.

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