chapter 9
Post on 12-Jan-2016
76 Views
Preview:
DESCRIPTION
TRANSCRIPT
Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition
Chapter 9
Human Energy Expenditure During Rest and Physical Activity
Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition
Energy Expenditure at Rest
• Basal metabolic rate (BMR)– Energy to maintain vital functions in awake
state
• Resting metabolic rate (RMR)– Energy to maintain vital functions plus
digestion– Measured 3 – 4 hours following a meal
Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition
Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition
Metabolism at Rest• Resting energy metabolism varies in
proportion to the body’s surface area
• Allometric scaling is used to – Establish a relationship between body size and
a variable such as• Muscular strength
• Aerobic capacity
Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition
Effects of Regular Exercise
• Resistance training increases BMR by increasing FFM.
• Endurance training increases BMR without increasing FFM.
• Exercise can offset the age-related decline in BMR.
Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition
“Normalcy” of BMR Values
• Compares a person’s measured BMR with “standard metabolic rates” based on age and gender
Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition
Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition
Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition
Estimating Resting Daily Energy Expenditure
RDEE = BMR × m2
• Contribution of diverse tissues– Muscle is more active than fat mass.– The brain has a high metabolic rate.– During exercise, muscle metabolism may increase
nearly 100 times.
Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition
Factors that Affect Energy Expenditure
• Physical activity– Largest variable in daily energy expenditure
• Diet-induced thermogenesis (DIT)– Obligatory thermogenesis– Facultative thermogenesis
Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition
Factors that Affect Energy Expenditure
• Climate– Hot or cold environments increase energy
expenditure.
• Pregnancy– Increases BMR due to added weight gained
during pregnancy
Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition
Energy Expenditure in Physical Activity
• Classification of physical activities by energy expenditure– Intensity– Duration
• Physical activity ratio (PAR)– Determined by ratio of energy required in relation to
BMR• Light work = 1 – 3 × BMR• Heavy work = 6 – 8 × BMR• Maximal work = > 9 × BMR
Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition
The MET
MET = metabolic equivalent
– 1 MET = 3.5 mL × kg−1 × min−1
– Exercise intensity described relative to resting rate
– Used to guide or prescribe exercise intensity
Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition
Daily Rates of Average Energy Expenditure
• The average U.S. adult spends 75% of the day in activities requiring light energy expenditure.
• In the United States, 300,000 deaths per year result from physical inactivity and poor eating habits.
Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition
Energy Cost of Household, Industrial, and Recreational Activities
• Effect of body mass– Weight-bearing exercise– Weight-supported exercise
Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition
Heart Rate to Estimate Energy Expenditure
• Heart rate and oxygen consumption– Linear relationship exists– Linearity is not identical for everyone
• Other factors altering heart rate– Temperature – Humidity– Food intake – Body position– Muscle groups worked – Emotions– Static v. dynamic work
Copyright © 2007 Lippincott Williams & Wilkins. McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition
top related