Exercise Physiology:
 physiology: the sum of all biologic processes
 what happens to these processes when
exercise
Metabolism: sum total of all
processes occurring in living
organisms
 catabolism: breakdown
 anabolism: build up
Energy transductions or
conversions are limited by the
laws of thermodynamics
Energy is transferred or
converted
 food converted to fat
 light and CO2 make sugar
Measured in kilocalories
 amount of energy necessary to raise the
temperature of 1 lit of water one degree
Celsius
Energy then, is related to the
ability to perform work
Can measure the capacity for
maximal work capacity in man
 via exercise physiology
1st law of thermodynamics:
 energy is neither created nor destroyed
 it is converted or transformed from one form
to another
Energy can be categorized as
 potential energy (amount of energy in canoe
on top of falls)
– can be light, electric, or bound
 kinetic energy (amount of energy in canoe at
the bottom of falls)
– energy of motion
Energy-releasing and Energyconserving processes
 must be coupled
 exergonic processes release or “frees”
energy
– downhill
 endergonic processes release of “store”
energy
– uphill
Transfer of potential energy is
unidirectional, to kinetic
energy, lowering the energy to
do work
This parallels the second law of
thermodynamics:
 potential energy gradually decreases,
entrophy increases
 the reactions in the body move towards
spontaneity, disorder, and randomness
Energy conversions
 photosynthesis
 respiration (part of energy converted can be
utilized for different work in the human body)
Biologic work in humans:
Bioenergetics
 mechanical (muscle contraction)
 chemical (biosynthesis of cellular molecules)
 transport (concentrating chemicals in intra
and extracellular fluids)
Factors affecting the rate of
bioenergetics:




enzymes
coenzymes
mass action
temperature
Hydrolysis and Condensation
 hydrolysis: complex organic molecules are
catabolized to simpler forms for assimilation
 condensation: molecule of water is formed
in this anabolic process
Oxidation and Reduction rxns
 oxidation: transfer of either oxygen or
hydrogen atoms, or electrons
– loss of electrons, gain of valence
– oxidizing agent is electron acceptor
 reduction: gain of either oxygen or
hydrogen atoms, or elctrons
– gain of electrons, loss of valence
– reducing agent is electron donor
 together are called redox reaction
e.g.
 NAD to NADH + H or FAD to FADH2
Energy Expenditure
Measurements:
 Direct
– bomb calorimetry
 Indirect
– closed circuit
– open circuit
ATP, energy currency of the body
 stores small amounts, 85g or 3 oz
 intermediate compound
 part of energy receiver-energy donor
cycle
 all energy can be transformed or
converted to ATP equivalents
 ATP equivalent is the energy differential
in the conversion of ATP to ADP, and
vice versa
Cleaving of ATP
 the cleaving of ATP, hydrolysis of ATP can
occur in the presence or absence of oxygen
is termed nonaerobic