EXPH 365 1st Edition Lecture 6Energy expenditure- Measured in calories (heat given off of body) - 1 cm3 of water raised one degree Celsius- Direct calorimetry- measure heat productiono Insulated chamber (joules) absorbed by water in copper pipes and measure temperature- Indirect- measure oxygen consumption (+/-%)o Closed- spirometry rebreathe same air o Open- room air (more activities) Pros of Indirect- Not as time consuming- Field test- Different fuel sources identifiedCons of Indirect- Expensive- Sensitive equipment- Based on estimatesOxygen consumption - First measure amount of oxygeno Closed chamber (100%)o Open (20.93%)- 2nd measure oxygen in expired air- Take the difference- Two ways to expresso Absolute VO2o Relative VO2***1 Liter of oxygen = 5 calories expended***Respiratory Quotient (RQ)- RQ= CO2 produced/O2 consumed o CO2 from Krebs cycle and O2 from electron transport- RQ = 1.00 for carbs, 0.70 for lipids, 0.82 protein, 0.82 for mixed diet- Carb is absolute highest number (1.00)Respiratory exchange ratio (RER)- Ratio CO2 and O2 at mouth- Difference = higher valueResting Energy Expenditure- Basal Metabolic Rate (BMR)o 60-75% of energy used just to stay alive- BMR—oxygen consumptiono 12 hours no eatingo 12 hours no exerciseo 30-60 minute measurement- METS—metabolic equivalents o 1 met (avg. rest oxygen consumption)o 1 met ~ 250 mL/min = 3.5 mL/( kg x min)- Males 1800-2000 calories/day- Females 1300-1500 calories/day (affected by muscle mass)Dietary induced thermogenesis - Food increase energy metabolism o Digest nutrients, absolute nutrients, assimilate nutrients- Effects of climateo Warm—increase BMR, increase oxygen, sweat, circulatory dynamicso Cold—increase BMR, increase, increase oxygen consumption, shivering- Energy Expenditure during exercise o Gross and netMETS method- Economy of movement- Recovery (EPOC**) **know definition- Fast—low intensity (30s is ½ EPOC)- Slow—high intensity (weight lifting) high
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