Lecture 3

Question 1

Basal Metabolic Rate

Answer 1

1. minimum level of energy required to sustain vital functions in waking state
2. BMR is measured under very stringent laboratory conditions

Question 2

Resting Metabolic Rate (RMR)

Answer 2

• measured under slightly less stringent conditions (3-4 hrs after a light meal); a slightly higher value results

Question 3

RMR is strongly influenced by:

body composition

Answer 3

• Those with more fat free mass (FFM) have a higher RMR
  
  • FFM = everything but lipids
• Largely explains the lower RMR in women, as women have a lower FFM for a given mass compared to men

Question 4

RMR decreases with advancing ___

Answer 4

Age; 2-3%loss per decade during adulthood

• Loss of FFM (muscle) with aging
• Increasing FFM will offset usual aging-related fall in RMR

Question 5

Ingestion of food increases:

Answer 5

metabolism

• energy required for digestion, absorption and assimilating nutrients
• Equivalent to 10-35% of ingested calories
• Large genetic component
• whether thermic effect of food is decreased in obesity is still debated - effect is probably small

Question 6

NEAT

Answer 6

the energy expenditure associated with daily activity, such as posture (sitting, standing, lying) spontaneous ambulation (walking) and talking

Question 7

NEAT - study in small number of lean and mildly obese couch potatoes

Answer 7

• Obese individuals had a smaller NEAT due to more sitting than standing or ambulation
• If they adopted the same #min of ambulation as the lean group, the obese group would expend an additional ~300kcal/day

Question 8

MET

Answer 8

Multiple of VO2 (a measure of absolute intensity)

1MET = 3.5mLO2/kg/min

Question 9

Gross expenditure

Answer 9

net cost of the activity +RMR during that time period

Question 10

Net energy expenditure

Answer 10

Gross - resting

Question 11

Body mass affects total energy expenditure for a given activity, particulalry..

Answer 11

• Weight-bearing exercise (walking, stepping,mowing the lawn)
• Heavier the person (or external weight carried, like a backpack, the more energy expended during the activity)
• Non WB Exercise: effect of body mass on VO2 is much less, because body mass is supported

Question 12

Efficiency equation

Answer 12

Gross efficiency: work output/energy expended *100

Question 13

Efficiency for different activites

Answer 13

• Ranges from 20-30% for walking, running, and cycling - can be less than 10% for swimming
• Wasted energy due to friction
• Skill depdendent

Question 14

Efficiency decreases as workload increases

Answer 14

Question 15

Economy of movement

Answer 15

oxygen consumed during a specific exercise at a set power output or speed

Question 16

Economy of movement is affected by:

Answer 16

• skill in performing activity
• Terriain or surface for walking, running
• gait mechanics or use of assistive devices