ENVIRONMENTAL
EXERCISE PHYSIOLOGY
ENVIRONMENT
• The sum total of all the conditions and
elements which make up the surroundings
and influence the development of an
individual. This course primarily focuses
on the thermal environment, influences of
barometric pressure (hypobaria and
hyperbaria), quality of air, and
microgravity.
ECOLOGY
• Branch of biology that deals with the
relations between living organisms and
their environment. An organism is the
center of an ecosystem; and is influenced
by a multitude of living things and yet
capable of resisting to some extent the
impact of the environment.
CONFORMING VERSUS
REGULATING ORGANISMS
• The internal conditions of conforming
organisms are more closely related to the
conditions of the surrounding
environment whereas the regulating
organisms are capable of maintaining a
relatively constant internal environment
(homeostasis) despite widely fluctuating
environmental conditions
REGULATING ORGANISMS
• Humans are an excellent
example of regulating
organisms and because
of this ability, the human
is referred to as a
homeotherm or warmblooded organism; and
consequently can
survive in diverse
environments
(ecosystems).
CONFORMING ORGANISMS
• Poikilotherm is a cold
blooded animal and
although they tend to
have a wider range of
internal variation, they
tend to have a narrower
environmental survival
range than a
homeotherm because of
a lesser ability to
regulate their internal
environment.
CONFORMING VERSUS
REGULATING ORGANISMS
Early Example of Humans as an
Regulating Organism
• In the 1700’s the Secretary of the Royal Society
of London, Mr. Blagden along with his dog, an
egg, and a steak entered a room heated to 105
degrees C (221 degrees F) which was above the
boiling point for water.
• Fifteen minutes later the egg was baked hard and
the steak was burnt crisp; Mr. Blagden and his
dog walked out unharmed (dog was carried in a
basket so his feet did not get burned).
THERMAL ENVIRONMENT
• A biophysical aggregate of air
temperature, wind speed, relative
humidity, and radiation.
TEMPERATURE
• The degree of sensible heat or cold; a
measure of the escaping tendency of
heat from a system (temperature flows or
moves from hot areas to cold areas); the
property of a system that determines
whether or not the system is in thermal
equilibrium with other systems.
LAWS OF THERMODYNAMICS
• Zeroth Law - two systems in
thermoequilibrium with a third
system are in thermoequilibrium with
each other.
LAWS OF THERMODYNAMICS
• First Law - energy is conserved in any
process; the energy gained (or lost) by a
system is exactly equal to the energy
gained (or lost) by the surroundings.
• Heat Balance Equation is derived from the
First Law of Thermodynamics.
Heat Balance Equation:
S = M - (+ Wk) - E + R + C + K
• S = Heat Storage
• M = Metabolism
• Wk = Work: where + is positive work representing
energy leaving the system and - is negative or
eccentric work
• E = Evaporation: insensible exchange of heat via
vaporizing moisture
• R = Radiation: sensible exchange of heat via
electromagnetic waves
• C = Convection: sensible exchange of heat via a
circulating medium
• K = Conduction: sensible exchange of heat via a
static medium
LAWS OF THERMODYNAMICS
• Second Law - there is always an
increase in entropy in any naturally
occurring (spontaneous) process.
Entropy refers to increasing
disorder; or diminished capacity for
spontaneous change, as occurs in
aging.
LAWS OF THERMODYNAMICS
• Third Law - absolute zero is
unattainable; to approach absolute
zero (i.e., the temperature where
molecular motion stops) takes
increasing amounts of energy.
Absolute zero is equal to 0o Kelvin, 273o Celsius, or - 460o Fahrenheit.
QUESTIONS?
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