[From Bruce Abbott (950615.1600 EST)]
Bob Clark (950613.1718 EDT) --
Thanks, Bob, for your interesting observations on fatigue, from an
"experiment" no one would wish for. You are a true explorer of a landscape
unknown to most of us and, as scientist, you have collected your data and
provided a possible interpretation consistent with the facts. Nice going.
Some comments:
THREE FORMS OF "FATIGUE"
I. "BRAIN FATIGUE" characterized by increased rate and depth of breathing,
and observed both in the presence and in the absence of muscle activity.
Fairly rapid recovery, minutes, not hours.
It is unclear from your earlier description whether muscle activity was or
was not present: the primary criterion seemed to be that you had no
sensation of muscle fatigue coming directly from the muscles. Perhaps
"brain fatigue" is just muscle fatigue without the direct feedback. If the
muscles are actually contracting, the energy expendature would soon deplete
oxygen in the blood and lead to faster breathing: in experiments using
direct electrical stimulation of muscles in paraplegics, the change in
breathing and heart rate is how the participants recognized that they were
"running out of energy." Also, I wonder whether, in the absence of actual
muscle contraction, the autonomic and hormonal systems are activated in
parallel in "anticipation" of the added demand for oxygen to the muscles.
Might this autonomic/hormonal activation lead to your perceptions?
A second comment is that I get another kind of "brain fatigue" all the time:
I'm just too tired to think, even though I might not feel the least bit
sleepy. Would this be related to your "brain fatigue" category? "Gland
fatigue?" Yet another category of fatigue?
A final question on a somewhat different topic, if you don't mind. Judging
from your description, you have suffered a right-hemisphere stroke involving
at least the motor cortex. In addition to the obvious motor difficulties,
have you noticed any other difficulties? Have any been pointed out to you
that you didn't notice?
Good luck with your continued recovery!
Regards,
Bruce