As our team traveled to San Diego this past weekend we were
stoked about running at sea level. We
knew that for each breath we were taking our lungs would receive more oxygen
than what we were used to in Denver. No
matter the elevation, however, a runner and any other competitive athlete will
experience extreme fatigue in competition.
The burning question that Drs. Ross Tucker and Jonathan Dugas explore in
“The Science of Sport” article is whether fatigue is caused by actual
physiological changes in the body, or whether it’s all in the brain such as a
“mental block”.
As many topics in sports end up, the answer is a little bit
of both. Interestingly enough this
article explains that there is sufficient evidence that both changes in your
cells cause fatigue, while the brain also acts in a powerful way involved with
fatigue.
One theory believes that you become fatigued because your
muscles run out of oxygen as you approach your VO2 max. The physiology that supports this says that calcium
channels become more “leaky” throughout exercise, which causes the force of
muscle contractions to be reduced.
During intense exercise phosphate and Hydrogen ions are at their peak,
along with body temperature at it’s highest.
The combination of these physiological changes result in the body slowing
down, which is perceived as fatigue.
The second theory believes that the body slows down which is
often characterized as fatigue because the brain anticipates extreme exercise
and warns the body before the above physiological changes occur. The brain is a one big regulation system,
which requires the body to slow down in order to prevent reaching high body
temperatures, lack of oxygen, or lactic acid build up.
Interestingly enough, these scientists know that the mind is
a very powerful agent. It can often push
the body to extreme lengths with an intense amount of willpower. However, when it comes to analyzing fatigue
in competitive athletes, physiology always wins. No factor can trump the evidence collected
with the many chemical changes occurring in the muscles during exercise. With these theories in mind I will leave you
with this interesting fact. Less muscle
is activated during most exercises in the heat than in cool conditions. This supports the idea that the mind can help
to push your limits in any conditions, but the body will always respond to the physiological
changes.
Reference:
Tucker,
Ross, and Jonathan Dugas. "The Science of Sport." The Science of
Sport. N.p., May 2008. Web. 10 Oct. 2013.
Interesting, I wonder if the brain is plastic with respect to fatigue perception? Personally, coming back from an exercise hiatus of even a week or so makes working out feel so hard! I don't know how fast muscle atrophy occurs, but surely it can't be responsible for how terrible I feel while running after one week of no exercise. My blog post was about arm wrestling and muscle fiber types, where professional arm wrestlers were likely to have fatigue resistant Type II muscle fibers attributed to repetitive training. Training might also affect the brain then!
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