Human Metabolism

1
Human Metabolism

• Metabolic Rate
• Fitness
• Efficiency

2
Metabolism

• Internal energy comes from food
• Oxidation of food supplies energy
• Energy goes into
• Internal functions
• External work
• Excess expelled as heat
• Rewrite in terms of rates

• ?U/?t lt 0
• Must replenish U with food
• The metabolic rate (?U/?t) is the rate at which
  food and oxygen are converted to internal energy
  to balance loss through Q W

3
Metabolic Rate

• Metabolic Rate directly proportional to volume of
  oxygen consumed
• ?U/?t in kcal/s
• ?VO2/?t in L/s
• Can measure ?VO2/?t to determine metabolic rate
• Can measure W/?t to determine power output
• Use to find efficiency

4
Metabolic Rates
p. 415
Basal metabolic rate is the rate when sleeping
5
Physical (Aerobic) Fitness

• Aerobic fitness is a measure of a persons
  maximum capacity to use oxygen
• Increases with exercise
• Decreases without

p. 416
6
Efficiency

• Body does work ? can function as a machine
• Define efficiency as before
• Affected by the type of work done

p. 416