Use of the doubly labeled water technique in humans during heavy sustained exercise
We measured energy expenditure with the doubly labeled water technique during heavy sustained exercise in the Tour de France, a bicycle race lasting more than 3 wk. Four subjects were observed for consecutive intervals of 7, 8, and 7 days. Each interval started with an oral isotope dose to reach an excess isotope level of 200 ppm 18O and 130 ppm 2H. The biological half-lives of the isotopes were between 2.25 and 3.80 days. Energy expenditure was compared with simultaneous measurements of energy intake, and body mass and body composition did not change significantly. The doubly labeled water technique gave higher values for energy expenditure than the food record technique. The discrepancy showed a systematic increment from the first to the third interval, being 12.9 +/- 7.9, 21.4 +/- 9.8, and 35.3 +/- 4.4% of the energy expenditure calculated from dietary intake, respectively. Possible explanations for the discrepancy are discussed. The subjects reached an average daily metabolic rate of 3.4-3.9 or 4.3-5.3 times basal metabolic rate based on the food record technique and the doubly labeled water technique, respectively. Thus, when measured with the same technique, the energetic ceiling for performance in humans is comparable with that of animals like birds.
- Research Organization:
- Univ. of Limburg, Maastricht, The Netherlands
- OSTI ID:
- 6647184
- Journal Information:
- J. Appl. Physiol.; (United States), Vol. 6
- Country of Publication:
- United States
- Language:
- English
Similar Records
Use of doubly labeled water technique in soldiers training for jungle warfare
Validation of doubly labeled water for measuring energy expenditure during parenteral nutrition
Related Subjects
MAN
ENERGY BALANCE
EXERCISE
BIOLOGICAL HALF-LIFE
DOUBLE LABELLING
ENERGY
HEAVY WATER
MEASURING METHODS
METABOLISM
OXYGEN 18
WATER
ANIMALS
EVEN-EVEN NUCLEI
HYDROGEN COMPOUNDS
ISOTOPES
LABELLING
LIGHT NUCLEI
MAMMALS
NUCLEI
OXYGEN COMPOUNDS
OXYGEN ISOTOPES
PRIMATES
STABLE ISOTOPES
VERTEBRATES
551001* - Physiological Systems- Tracer Techniques