Cardiovascular function and muscle studies on "lifelong" exercisers

Gries et al from Ball State Human Performance Lab have published the results of a study of cardiovascular  function and muscle enzyme levels on long term aerobic exercisers who did aerobic exercise for fifty (50 !) years and compared them to non exercisers of comparable age and to young exercisers.

The life time exercisers were divided into 2 groups based on the intensity of lifelong exercise  with the "performance" group consisting on competitive runners and the others called the "fitness" group which I take to mean they exercised to be fit and were not competitive athletes.Both subgroups of the
lifelong exercisers exercised 5 days per week with an impressive 7 hours of exercise per week.

The maximal oxygen consumptions values were , (expressed as ml/kilo/min):

performance group 38.1 +/-1
fitness group  27.1 +/- 2
young exercisers 53 +/- 3

Not surprising that the competitive group would have a significantly higher 02 max.In regard to muscle enzyme levels there were no differences between the competitive and fitness groups and levels were similar to the values seen in the young group.

Similar values for 02 max in  longterm exercisers were reported  (1) by Benjamin Levine's group from Southwestern. They also reported a significant higher 02 max in the competitive subgroup versus the non-competitive subgroup ( 39.5+/- 5.3 versus 32.5+/-5)

These two studies present data on two subgroups of long time or "lifelong" exercisers with the competitive groups having significantly higher maximal oxygen uptakes. Both subgroups exercised for many hours a week but presumably the competitive group in each study exercised at a higher intensity. Is the difference in measured maximal oxygen uptake due to the intensity of training or is the difference due to the competitive group having the genetic endowments that  bestow a super compliant left ventricle capable of rapidly  filling and allowing a higher exercise stroke volume.

1) Bhella PS , Impact of lifelong exercise "dose"on left ventricular compliance and distensibility
JACC vol 64 2014