Ex Nutr c3-energy1 Measuring energy expenditure Direct calorimetry Indirect calorimetry Douglas bag Breath-by-breath systems

Ex Nutr c3-energy2 Bomb calorimeter

Ex Nutr c3-energy3 Bomb calorimeter

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5

6 Direct calorimetry chamber

Ex Nutr c3-energy7 Direct calorimetry chamber

Ex Nutr c3-energy8 Closed circuit method

Ex Nutr c3-energy9 Closed circuit method

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Ex Nutr c3-energy12 Douglas bags

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Ex Nutr c3-energy14 Indirect calorimetry and substrate utilization Assume protein is not important energy source In some extreme conditions, protein may provide up to 15% energy expenditure Correction for protein oxidation Protein oxidation estimated from nitrogen content in urine

Ex Nutr c3-energy15 Calculate CHO and fat oxidation rate using VO2 and VCO2 Assume protein oxidation is zero

Ex Nutr c3-energy16 Adjusted for protein oxidation

Ex Nutr c3-energy17 RER vs RQ Respiratory exchange ratio (RER, or R) measured at mouth does not always reflect oxidation process in cells (respiratory quotient, RQ) Hyperventilation: excess CO 2 expired Extra excretion of body CO 2 stores (HCO 3 - in extracellular fluid) Buffering of H+ H + + HCO 3 -  > H 2 CO 3 <  H 2 O + CO 2

Ex Nutr c3-energy18 Doubly labeled water Administration of bolus dose of 2 stable isotopes of water: 2 H 2 O, H 2 18 O 18 O lost in water and as C 18 O 2 2 H (deuterium 氘 ), 3 H(tritium 氚 ) lost in water alone Difference between 2 tracer excretion rates represents CO 2 production rate Unbiased measurement of free-living situation Relatively long-term (days, weeks) estimation of energy expenditure Also use H 13 CO 3 Equilibrium with body’s CO 2 pool

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Ex Nutr c3-energy20 Muscle biopsy

Ex Nutr c3-energy21 Other methods in estimating EE Heart rate monitoring Require individual relationship between HR, VO2, EE Accelerometer 1, 2, or 3 axes Combine HR monitoring and accelerometer Activity records 24 hr, 1 week, or 1 month recall

Ex Nutr c3-energy22 Components of Energy Expenditure Total energy expenditure = Basal Metabolic Rate (BMR) + TEA+TEF+AT Basal metabolism: energy expanded during nonactive rest (just waking) Thermal Effect of Activity (TEA) Thermal Effect of Food (TEF): associated with consumption of food, digestive, absorption, metabolism Adaptive Thermogenesis (AT): in response to change in environmental temperature, increase blood flow to skin, shivering BMR (kcal/kg) varied by %FFM Highest in infancy, decline with age Can be estimated by equations

Ex Nutr c3-energy23 Components of total energy expenditure

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Ex Nutr c3-energy29 Energy costs of different activities

Ex Nutr c3-energy30 Energy costs of different activities

Ex Nutr c3-energy31 Energy costs of different activities

Ex Nutr c3-energy32 Upper limits of energy expenditure Well-trained athletes can expend ~1000 kcal/h for prolonged periods of time Up to 9000 kcal/d in Tour de France More than kcal/d in extreme long- distance running Energy requirements can be met by most athletes, if well-planned (e.g. 20% CHO solution during exercise)

Ex Nutr c3-energy33 Energy balance in Tour de France

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Ex Nutr c3-energy36 Components of energy expenditure Resting metabolic rate, basal metabolic rate Diet-induced thermogenesis, thermic effect of food Thermic effect of exercise

Ex Nutr c3-energy37 International physical activity questionnaire, IPAQ

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Ex Nutr c3-energy41 Popular fat-buring tricks - 1 May not useful, depend on exercise type/intensity/duration and individual needs Carbohydrate tapering: eat high CHO in morning after ex, low CHO remaining the day Promote recovery of glycogen after exercise Burn more fat at night and during sleep Glycogen recovery may take several hours or longer after ex, may insufficient recovery Cardiomorning: perform endurance ex in morning Low glycogen before breakfast, more fat burning during ex Can only perform morning exercise at lower intensity May not reach maximal fat oxidation

Ex Nutr c3-energy42 Energy from fat in exercise with different intensities

Ex Nutr c3-energy43 Fat expenditure in exercise with different intensities

Ex Nutr c3-energy44 Popular fat-buring tricks - 2 Afterburn: not eating for several hours after endurance ex Increase fat oxidation after ex May induce protein breakdown after strenuous ex Light ex may not elicit sufficient fat oxidation Iron the cardio: weight training before endurance ex Decrease muscle glycogen during weight training, force higher fat oxidation during subsequent endurance ex Must involve the same muscle groups Higher intensity of endurance ex may negatively influence effect of resistance training on protein turnover Heavy endurance training should separate from weight training with the same muscle groups

Ex Nutr c3-energy45 A bout of endurance ex on protein turnover: post-ex supplementation

Ex Nutr c3-energy46 Designing optimal training diet for sport performance Determine energy expenditure Set goals for body weight and composition Set practical goals for distribution of diet energy into CHO, protein, fat In g/kg BW and en% Endurance athletes focus more on CHO, power athletes focus more on protein Distribute energy intake throughout meals and snacks during a day Timing is important Special attention to the first meal of the day Consider time of workout/training/work/class

Ex Nutr c3-energy47 Example: 75 kg male runner maintain weight, 4300 kcal/day

Ex Nutr c3-energy48 Example - continued