Basic concepts in energetics

1. Know the following Terms and Definitions:

a. Workload:  Refers to the exercise bout intensity. Usually measured as the amount of force being moved over given distance.
Usually expressed as kilogram-meters or joules.

b. Power output: Refers to the amount of work produced over a given time interval. Usually expressed as kilogram-meters per minute or joules per second (watts) (1 watt = 6.12 kpm).

c. Heart rate (HR): rate of heart beat, measured in beats per minute (bpm)

d.  Ventilation, typically measured as VE, volume of air expired by the lungs per minute (units =liters air per minute). Ventilation is a function of breathing frequency (f) and tidal volume (TV).

                      VE = f x TV

                  f = frequency of breathing (breaths per min)

                 TV = amount of air moving into and out of the
                      lungs per breath

e. Fraction of expired oxygen: refers to the fraction of oxygen found in expired air (FeO2). Used to calculate volume of oxygen utilized. Fraction of oxygen in inspired air (FiO2) is .2093. The fraction of oxygen in expired air (FeO2) during exercise will vary (i.e., .1500-.1800).

f. Fraction of carbon dioxide: refers to the fraction of carbon dioxide found in expired air (FeCO2). Used to calculate volume of carbon dioxide produced.  Fraction of carbon dioxide in inspired air (FiCO2) is 0.0003. Fraction of carbon dioxide in expired air will vary (i.e., .0200 - .0350).

g. Volume of oxygen utilized (VO2): is a function of the amount of oxygen in inspired air, expired air and ventilation.  Expressed either as absolute (liters per minute; l/min) or relative (milliliters per kilogram body weight per minute; ml/kg/min) units.

Absolute amount of oxygen utilized (liters of oxygen per minute),

      VO2 (liters/min) = VE(.2094-FeO2)

 Relative amount of oxygen utilized (milliliters oxygen per
 minute per kilogram body weight),

      VO2 (ml/min/kg) = VO2 (ml/min) / kg body weight

h. Volume of carbon dioxide produced (VCO2): is a function of the amount of carbon dioxide in inspired air, expired air and ventilation.

 Absolute amount of carbon dioxide utilized (liters of carbon  dioxide per minute),

      VCO2 (liters/min) = VE (FeCO2 - FiCO2)

 Relative amount of carbon dioxide utilized (milliliters of
 carbon dioxide per minute per kilogram body weight),

      VCO2 (ml/min/kg) = VCO2 (ml/min) / kg body weight

I. Respiratory exchange ratio (RER): the ratio of volume of carbon dioxide produced to the volume of oxygen utilized. Provides a means of accessing the relative percent contribution of fats and carbohydrates during exercise.

J. Bioenergetics: science that involves studies of energetic events

K. System: Organized functional unit (i.e., human, cellular organelles; boundaries of the systme will vary, must define)

L.  Surroundings: Environment around system. Everything else except
the system. There must be an interaction between a system and its surroundings, that is, an exhange of matter and energy. The energy level drops as a human performs work; therefore, an exchange of matter between a system (i.e., the human) and its environment is important.

M.  Universe: System plus the surroundings.

N. Energy: The capacity to do work. Types of energy include: nuclear (sun), light (sun light), chemical (sugar, fat, protein), mechanical (muscular contraction), electrical (nervous impulse), and heat energy.

O.  STPD,   refers to the volume of gas expressed as Standard conditions of Temperature (273 K or O (zero) Celcius), Pressure (760mmHg), Dry (no water vapor in gas).  Expressing a gas volume as STPD makes it possible to compare measurements while running in the rain on the beach in California, along a trail in the Rocky mountains, or running in the desert below sea level.

P.  BTPS,    refers to a volume of gas expressed at body temperature (usually 273 K + 37 Celcius (body temperature) or 310 K), ambient pressure (barometric pressure), and saturated with water vapor with a partial pressure of 47 mmHg (partial pressure of water in the respiratory tract.

Q. ATPS,    refers to the volume of gas at the specific conditions of measurement, which are therefore at ambient temperature (273 K + ambient temperature, Celcius), ambient pressure, and saturated with watervapor.