Energy expenditure measurement

Isotope ratio mass spectrometry, energy expenditure measurement, 303 Ita i-i tai disease, 811... 

Coward, W. A., Prentice, A. M., Murgatroyd, P. R., Davies, H. L., Cole, T. J., Sawyer, M., Goldberg, G. R., Halliday, D., and Macnamara, J. P. (1984). Measurement of COj and water production rates in man using H, -labelled H2O comparison between calorimeter and isotope values. In Human Energy Metabolism Physical Activity and Energy Expenditure Measurements in Epidemiological Researdi Based Upon Direct and Indirect Calorimetry (A. J. H. van Es, ed.), pp. 126-128. EURO-NUT, The Netherlands. 

Equations (9-59), (9-60), (9-61), and (9-62) may be used as they stand to assess expenditure on energy-conservation measures since a constant amount of energy is saved in each year subsequent to the capital outlay. However, the annual cash flows Acf corresponding to the energy savings remain constant only if there is no inflation or if the money values are corrected to their purchasing power at the time of the capital expenditure. 

Schoeller, D.A. 1988 Measurement of energy expenditure in free-living humans by using doubly labeled water. Journo/of Nutrition 118 1278-1289. 

Energy Requirements Are Estimated by Measurement of Energy Expenditure... 

Energy expenditure can be determined directly by measuring heat output from the body but is normally estimated indirectly from the consumption of oxygen. There is an energy expenditure of 20 kJ/L of oxygen consumed regardless of whether the fuel being metabo-... 

In a recent patent application, mice treated with a related iron chelator, deferasirox (DFS), showed reduced body weight while on a high fat diet compared to untreated controls. Additionally, DFS was claimed to improve whole body metabolism and energy expenditure as measured by increased 02 consumption and C02 production as well as a reduction in white adipose and visceral fat, despite little difference between food intake in the control and treated animal groups [25]. 

Sophisticated methods for assessing energy expenditures of hospitalized patients are now commercially available. One such method to calculate the REE involves the use of Vco, and V0, in expired air. An indirect calorimetric assay is employed to measure Vco, and V0, from the mechanically ventilated patient. REE can be calculated as follows ... 

Use of formulae Until recently, practical methods were not available for measuring energy expenditure in patients in hospital. Consequently, formulae, based on weight, height, age and gender of the patient were, and still are, in use. The earliest formulae were published in 1919, by Harris Benedict, who studied 239 individuals aged 15-73. These were used for many years but the values were found to be too high. In 1985, a study on 7000 individuals provided new formulae known as Schofield standards (Schofield, 1985 Table 2.4). Whichever formula is used, it provides only approximate values, since metabolic rate varies markedly between individuals. 

Direct calorimetry Energy expenditure can be measured from the heat lost by an individual, which is the same as that produced. All the energy used in the daily activities of the body is released as heat. For example, the mechanical energy expended walking to work, sprinting for the train or running a marathon is converted into heat. The method used for measuring heat production is known as direct calorimetry (Box 2.1). The individual lives in a... 

The great advantage of the technique is that the measurements do not affect normal daily activities in any way, so it can be used to measure energy expenditure in a number of different activities or conditions (e.g. by cyclists in the Tour de France race, climbers on Mount Everest, members of a trans-Antarctic expedition, women during pregnancy or lactation, obese animals including humans carrying out their normal daily activities) (Prentice 1988). 

Quantitative studies of energy metabolism and fuel utilisation in very prolonged physical activity were performed by Mike Stroud during his Antarctic expedition with Ranulph Fiennes in 1992. One part of the study was measurement of energy expenditure by the dual isotope techniques (Chapter 2). Calculated over the whole expedition, the average daily energy expenditure of Stroud and Fiennes was 29 MJ but on particularly arduous days it increased to... 

Event Energy intake (MJ/day) Composition of diet (% total energy) Energy expenditure (MJ/day) as measured by ... 

The method used for measuring energy expenditure of patients is indirect calorimetry, aldiough it can be calculated from die Harris Benedict or Schofield equations (Ch ter 2). 

Energy expenditure is however, a quantity which may be measured only with extreme difficulty. Dosimetry of ionizing radiations therefore consists of determining a more easily measured change and then relating this to energy expenditure. 

Measurement of charge separation in gases, however, is not an easy operation and accuracies of a few per cent are obtainable only with extreme difficulty. Furthermore, the relation between dose measured in terms of charge separation in gases and actual energy expenditure in condensed phases is quite complicated. 

The reversal of increased energy expenditure with RS has also been observed in humans with measurements of metabolism (02 uptake and C02 output) after 1 night of brief frequent experimental arousals (29). Given the debilitated appearance, lesions of the paws and tail, and progressive elevations in white cell counts of the TSD rats, immune function was studied in these animals. 

Oxygen uptake is not very useful in studies of energy expenditure, since 30-40% of it is not used for phosphorylated oxidation or ATP resynthesis, but for other varieties of oxidation such as peroxic and enzymatic oxidation which results in the production of heat (Khaskin, 1981). In any case, the efficiency of oxygen uptake as measured from the PIO coefficient varies according to various eco-physiological factors (Verzhbinskaya, 1968 Arsan et al., 1984 Savina, 1992). The heat produced is dissipated into the environment, except in the case of certain very active fish that possess a heat-exchange mechanism (Stevens et al., 1974) permitting the body temperature to rise and thereby increase muscle power (Love, 1980, p.321). 

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