36. Human Bioenergetics Flashcards
What is the daily energy cost to maintain 1 lb (1 kg) of lean tissue at rest?
4.45 mls of O2 per minute at rest
What is the energy cost (kcals) of walking one mile? Running one mile?
100 kcal
What is the total energy cost of exercising on a bike ergometer at the ARC @ 150 Watts for 30 mins?
150 Watts x 4 = 600 Watts of total energy release
600 J/sec / 4187 J/kcal x 60 sec/min x 30 mins = 257.94 kcals
What is the total energy cost for a 50 kg person who works at 8 Mets for 1 hr?
8 Mets x 50 kg = 400 kcals/hr
In terms of calorie balance, what is the necessary prereq for loss of body fat stores?
Sustained calorie deficit
In terms of calorie balance, what is the necessary prereq for maintenance of body fat & weight?
calorie intake = calorie expenditure
What is the most likely outcome when an apparently healthy person begins to lose lots of body weight (> 10 lbs) w/o effort, exercise, or other conscious intervention?
Disease:
- stomach cancer
- severe depression
- AIDS
- TB
Why does exercise alone (w/o calorie restriction) rarely results in large scale loss of body fat?
People eat to overcome calorie deficit
In what special situation does instituting regular exercise often result in a 5-10% loss of body weight in free-feeding humans or rodents?
Initial change from sedentary state to regular training
If someone is systematically under-eating relative to her calorie need by ~500 Kcal each day (a 500 Kcal deficit), how long will it take her to lose 1 lb of fat?
1 lb = 3500 kcals
3500 kcal/1 lb x 1 day/500 kcal = 7 days/1 lb
How many Kcals are in a pound of human fat?
3500 kcal/lb
During a calorie-restriction, what are the roles of aerobic vs. resistive exercise?
- Resistance training provides “retention signal” for lean mass
- Aerobic exercise lowers energy deficit, increases metabolism
What role does exercise play in the maintenance of body weight in the free-feeding individuals?
- Preserve lean mass
- Focus weight loss onto fat
