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 CO 2 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

1 st 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 Energy- conserving 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 FADH 2

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