Don reports he got to five mph on an 18% grade in his last
treadmill test. Now, I am sure Chung will reject the science
I am going to cover in this post. After all, his god is not
bound by things like Newton's laws or the laws of
thermodynamics. But, for the rest of us mortals there is
some quantitative data easily obtained from Don's treadmill
run. I will try my best to do this in laymans language so it
is understandable to all.
First of all, what is the conversion for five mph and an 18%
grade into running on the flat? Well, the figures I have
seen quoted say that each foot uphill you have to climb is
equal to six feet on the flat. This means that for each 100
feet Don ran at five mph he climbed 18 feet. Using the
conversion factor of six this means that Don ran 100 foot on
the flat (for the five mph portion of his run) and a second
100 foot on the flat for his 18 foot climb. In other words
this incline, plus the belt speed equals running about 10
mph on the flat.
Now it is reasonable to ask if any human can run at a speed
of 10 mph for an hour. The answer is a resounding yes.
People run faster then this for over two hours in every
marathon of any significance. And marathons are not on flat
land in general as Chung seems to think. They usually have
lots of hills.
Let us just deal with the energy burn of the climb portion
of Don's run for the most of the rest of this post. The
climb portion is the portion that lends itself to easy
quantitative analysis.
Any high school student who has taken first semester physics
can calculate, based on Newton's laws, how much work Don did
in the climb per hour. I am not going to go thru the
detailed math. If you want the details go find a high school
student. But briefly the results are Don would climb about
1448 feet per hour. If I assume Don weighs 150 pounds then
the total work of this climb is 237 Kcal. Now, in the funny
world of biology Kcals are called calories. So, in the rest
of this post when I say cal or calories I mean Kcal.
Is 237 the only energy Don's body consumed in making this
climb? Not by a long ways. For instance Chung was critcal of
an analysis I did recently as I neglected friction between
the foot and the surface. Well, there is also friction in
the foot and anklke bones, in the knees and hips and a small
amount contributed by the shoulders during any run. So let
us just for the sake of satisfying Chung say that these
frictions add up to an additional 10% energy requirement.
Our total now is 260 cal.
Of course in order to elevate his body all those feet Don's
heart had to beat a lot harder as it had to move lots more
blood. I am sure Chung can supply a better number for the
calory burn of Don's heart then I have at my fingertips. But
if your basal metabolism is 75 cal per hour I suspect 20 of
that is simply to pump blood and operate your lungs. As Don
is working lots harder on the treadmill then at rest his
heart is probably going three times as fast say. So I will
throw in another 40 cal to cover increased heart/lung
functions. We are now up to 300 cal per hour energy burn.
If all this seems bad there is still more to come. The laws
of thermodynamics require that a considerable amount of
waste heat must be generated during exercise. Exercise is
enabled by a series of chemical reactions that start with
glycogen stored in your liver and muscle cells. When you
exercise your body changes this stored glycogen into
glucose. There is an energy waste in this conversion that
can not be used by the muscles to do useful work. The
glucose is transported to the site where it is needed and
reacts with oxygen to provide energy to convert a
biochemical called ADP into ATP. From an energy standpoint
this is a horrigbly inefficient process. Only 2/3 of the
energy from oxidation of the glucose winds up in the ATP
according to Mariella and Blau. The rest is waste heat your
body must get rid of by sweating. Finally the ATP reacts
with components in your muscle cells to cause the cells to
contract, again with waste heat production. Actually, I have
skipped over many, many steps and vast details of all the
actual chemistry involved. All you really need to understand
is that there are several reactions which occur in sequence
and every single one of them MUST by the laws of
thermodyanmics produce waste heat that the body can not use
to do useful work. In fact, Mariella and Blau in the book
they wrote "Chemistry of Life Processes" state that less
then 50% of the total energy winds up doing useful work. The
rest is all waste heat. This is why you sweat when you
exercise. If it were not for all this waste heat you would
not need to sweat.
So, let us be generous to the poor Chung. Let us say that
the energy efficiency is 50%. If nothing else thsi makes it
easy to calcultate. What this means is that 300 calories of
work above now requires a total of 600 calories per hour
simply to do the climb. This is of course twice what Chung
claims any normal human can possibly do. It does make a
person pause and wonder about Chung's position I think.
Particularly if you also add in another 500 plus calories
per hour for the run portion of the treadmill. This is not a
small difference between my calculated results and Chung's
unsubtantiated assertion. This is a huge difference. But I
am sure Chung will be able to point out where my analysis is
incorrect.
By the way, I also mentioned in a past post that the energy
burn during the exercise period was not the whole story by a
bunch. We may as well deal with that while we are here. I
started the above chemical pathway with glycogen. Well,
where did your body get this glycogen? It got it from the
carbs in the food you ate. Or it made it from the fats and
proteins in the food you ate. Well, we know now that every
chemical process must produce waste heat. When you digest
food and your body does the chemisty to make glycogen a
considerable amount of waste heat is produced. Ever notice
how warm you are after a big meal? That warmth is waste heat
from digestion and the subsequent chemical conversions that
occur. You do not burn these calories during exercise but
you sure will burn them after exercise to replace the spent
glycogen. This energy requirement that occurs after exercise
can amount to another 10% of the total calories you burn.
Then of course during exercise some cells are killed, both
muscle and blood. These must be replaced. Another after
exercise energy requirement.
I belive the above makes the point quite clearly that Chung
is simply wrong again.