I am not a fan of Eisenhower but there are things
related to our task that should be taken into consideration:
“Don't join the book burners. Don't think you are going to conceal faults
by concealing evidence that they ever existed. Don't be afraid to go in your
library and read every book…”
When we see evidence, we should not hide it if we want
to improve. There is a limit to
generalize evidence, and it will depend on the stage of our knowledge. We have to know better in order to improve.
There is research regarding neurons under low oxygen
pressure. We have an electronic device
called oximetry which can measure oxygen saturation in blood indirectly, and it
is non-invasive. Normal people can
tolerate 95% of oxygen saturation pressure measured by oximetry without getting short of
breath. Below 93%, it precipitates shortness of breath indirectly because it corresponds to high CO2 in blood. When working at the VA hospital we had Vets
having 60% of oxigen saturation at rest without using oxygen at home; 55% was needed for the
insurance to give oxygen at home. By
walking 50 meters and taking the blood gas sample standing, the Vets were able
to score below 55%. What is happening to
our neurons when we do not have enough oxygen pressure? There are studies done on animal (reptiles)
and mammals to understand this phenomenon in order to help patients with
strokes. We are generalizing evidence
because this kind of studies are related to speed training.
Is Exercise-Induced
Arterial Hypoxemia in Triathletes Dependent on Exercise Modality?
We
concluded that Exercise Induce Arterial Hypoxemia was greater during running
than cycling for a similar metabolic rate corresponding to training intensity
and that EIAH could thus be considered dependent on exercise modality.
There are generalizations in the above statement that
needs to be addressed:
1)
The
VO2 max is not the same for the different disciplines in these athletes; the
CO2 drive and O2 drive would be trigger differently. In other words, the metabolic rate is the
same but the training fitness is not the same for the two disciplines; lactate
threshold is not the same.
2)
The
hypoxic drive is not that important; breathing drive:
Normal
respiration is driven mostly by the levels of carbon dioxide in the arteries, which are detected indirectly by central
chemoreceptors when carbon dioxide crosses the blood brain barrier, forming
detectable Hydrogen ions, and directly by peripheral
chemoreceptors,
and very little by the oxygen levels. An increase in carbon dioxide will cause
chemoreceptor reflexes to trigger an increase in ventilation. Hypoxic drive
accounts normally for 10% of the total drive to breathe. This increases as the
PaO2 goes to 70 torr and below, while hypoxic drive is no longer active
when PaO2 exceeds 170 torr.
Please
read the article written by French researchers to follow me.
3)
Are
the French training more and more efficiently cycling than running? As a coach, this would be my guess. The CO2 diffusion is 20 time faster than the
O2 diffusion, breathing more rapidly helps to lose CO2 instead of increasing O2
to the same degree.
4)
What
we see is that hypoxemia is present when we are expecting the oxygen saturation
not to drop more than 4% from baseline.
5)
Hypoxemia
installs even when changing from running to cycling and stays there until the
end of the exercise period.
6)
Transitioning
appears to be necessary as training to improve our ability to cope with low
oxygen pressure. Swimmers sometimes
train 400 meters running (all out) before sprinting swimming.
Let’s go back to our subject of how the neurons adapt
to hypoxemia. The subject of neurons
adapting to low oxygen pressure is what gives SPEED. Studies were done and sponsored to help
patients with strokes when the O2 saturation decreases significantly.
First, oxygen signaling is well developed in hypoxia-tolerant neurons,
making them ideal models for studying signal transduction processes during
adaptations to hypoxia. Second, hypoxia-tolerant neurons are useful models for
distinguishing between injury and adaptation induced by hypoxia. This is of
obvious interest in determining the relevance of proposed therapeutic
interventions for patients with hypoxic or ischemic diseases. Third, these
neurons may help in the identification of entirely new targets for treating
diseases that involve hypoxia
This makes fartlek the training of choice. Without the hypoxic episodes, short in
duration and recovery al 60% with high cadence, the neurological changes to go
fast does not exist:
Hypoxia
Boosts Walking Ability in Spinal Cord Patients
Experimental models demonstrating that hypoxia therapy induces cellular
and physiological changes in the nervous system that translate into beneficial
plasticity and strength laid the groundwork for this new work, said Dr.
Trumbower.www.medscape.org
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