One-step N2-dilution technique for calibrating open-circuit VO2 measuring systems
Abstract
A simple one-step procedure that eliminates the need to calibrate the O2 analyzer or measure the flow past the animal is described for calibrating an open-flow respirometry system. The technique is particularly useful for situations of high ambient humidity and for large or active animals where a mask is employed to capture expired gases. A measured N2 flow is used to calibrate the system. The equations describing the technique are given, and the accuracy of the method is discussed in detail. The errors associated with the technique are compared with those of more conventional procedures and are usually smaller.
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The accuracy of the respirometry system (±4%) was validated by N2 dilution tests.
“The accuracy of the system (± 4%) was validated by N2 dilution tests45.”
From The peacock train does not handicap cursorial locomotor performance (2016) · cites this paper as [45]
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“Nitrogen leak tests (Fedak et al. 1981) while sliding the box on the bench surface indicated maximum errors of 4% in the calculation of V̇O2.”
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InfluentialSelf-citationEat now, pay later? Evidence of deferred food-processing costs in diving seals
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“The system was calibrated daily using known flow rates of nitrogen (Fedak et al. 1981).”
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“All values were corrected to stpd, and the entire system was calibrated before and after the tests with ambient air and nitrogen gas according to Fedak et al. (1981).”
MethodEffects of prior exercise on muscle metabolism during sprint exercise in horses
McCutcheon, L. J., Geor, R. J., & Hinchcliff, K. W. (1999) · Journal of Applied Physiology · doi:10.1152/jappl.1999.87.5.1914 · Cited by 67 · see citing works
“The overall accuracy of the system was verified repeatedly by the nitrogen dilution method (10).”
MethodHawkins, P. A. J., Butler, P. J., WOAKES, A. J., & Speakman, J. R. (2000) · Journal of Experimental Biology · doi:10.1242/jeb.203.18.2819 · Cited by 64 · see citing works
The Application of Ground Force Explains The Energetic Cost of Running Backward and Forward
Wright, S., & Weyand, P. G. (2001) · Journal of Experimental Biology · doi:10.1242/jeb.204.10.1805 · Cited by 63 · see citing works
José‐Cunilleras, E. L. V., Hinchcliff, K. W., Sams, R. A., Devor, S. T., & Linderman, J. K. (2002) · Journal of Applied Physiology · doi:10.1152/jappl.2002.92.1.117 · Cited by 65 · see citing works
“The overall accuracy of the system for the measurement of V̇O2 was verified for each run by the nitrogen-dilution method, and measured values were corrected for any discrepancy (10).”
MethodKING, C. M., EVANS, D. L., & ROSE, R. J. (1994) · Equine Veterinary Journal · doi:10.1111/j.2042-3306.1994.tb04373.x · Cited by 63 · see citing works
Kurta, A., Johnson, K. A., & Kunz, T. (1987) · Physiological Zoology · doi:10.1086/physzool.60.4.30157900 · Cited by 63 · see citing works
Sparling, C. E., Speakman, J. R., & Fedak, M. A. (2006) · Journal of Comparative Physiology B · doi:10.1007/s00360-006-0072-0 · Cited by 61 · see citing works
“The respirometry system was calibrated at the beginning of every run using the nitrogen dilution technique described by Fedak et al. (1981). Oxygen consumption of the seal was calculated using the following equation from Fedak et al.”
MethodInfluentialSelf-citationTesting optimal foraging models for air-breathing divers
Halsey, L. G., WOAKES, A. J., & Butler, P. J. (2003) · Animal Behaviour · doi:10.1006/anbe.2003.2090 · Cited by 60 · see citing works
“22) such that the oxygen uptake of the duck could be calculated (Fedak et al. 1981).”
BackgroundSeeherman, H. J., & Morris, E. A. (1990) · Equine Veterinary Journal · doi:10.1111/j.2042-3306.1990.tb04729.x · Cited by 60 · see citing works
Self-citationBarrickman, N. L., & Lin, M. J. (2010) · American Journal of Physical Anthropology · doi:10.1002/ajpa.21354 · Cited by 59 · see citing works
“To calibrate the system and account for daily fluctuations in flow rate, nitrogen dilution was performed on the day of each data collection session following the methods developed by Fedak et al. (1981).”
MethodUnderstanding respirometry chambers: What goes in must come out
Frappell, P. B., Blevin, H. A., & Baudinette, R. V. (1989) · Journal of Theoretical Biology · doi:10.1016/s0022-5193(89)80046-3 · Cited by 59 · see citing works
Heat Increment of Feeding in Brünnich’s Guillemot Uria Lomvia
Hawkins, P. A. J., Butler, P. J., WOAKES, A. J., & Gabrielsen, G. W. (1997) · Journal of Experimental Biology · doi:10.1242/jeb.200.12.1757 · Cited by 59 · see citing works
Minimum cost of transport in Asian elephants: do we really need a bigger elephant?
Langman, V. A., Rowe, M. F., Roberts, T. J., Langman, N., & Taylor, C. R. (2012) · Journal of Experimental Biology · doi:10.1242/jeb.063032 · Cited by 56 · see citing works
“The entire system was calibrated by metering nitrogen into the mask (Fedak et al., 1981) and the accuracy was better than ±2%.”
MethodAltitudinal variation in parental energy expenditure by white-crowned sparrows
Weathers, W. W., Davidson, C. L., Olson, C. R., et al. (2002) · Journal of Experimental Biology · doi:10.1242/jeb.205.18.2915 · Cited by 56 · see citing works
Geor, R. J., Ommundson, L., Fenton, G., et al. (2001) · Equine Veterinary Journal · doi:10.2746/042516401776563490 · Cited by 56 · see citing works
- Authors
- Fedak, M. A., Rome, L., & Seeherman, H. J.
- Venue
- Journal of Applied Physiology
- Publisher
- American Physiological Society
- Published
- 1981-09-01
- Volume
- 51
- Issue
- 3
- Pages
- 772-776
- ISSN
- 0161-7567 (ISSN-L)
- 8750-7587
- 1522-1601
- OpenAlex
- W2153755066
- Cited by
- 337
- References
- 0
- Citations by year
- 2026: 4 · 2025: 5 · 2024: 6 · 2023: 5 · 2022: 9 · 2021: 8 · 2020: 6 · 2019: 4 · 2018: 4 · 2017: 7 · 2016: 5 · 2015: 11 · 2014: 10 · 2013: 10 · 2012: 8
- FWCI
- 0.00
- Type
- journal article
- Language
- en
- Open access
- closed
- Locations
- Journal of Applied Physiology (publishedVersion)
- PubMed (publishedVersion)
- Topics
- Health Sciences › Medicine › Surgery › Biomedical and Chemical Research
- Health Sciences › Medicine › Complementary and alternative medicine › Cardiovascular and exercise physiology
- Physical Sciences › Environmental Science › Ecology › Physiological and biochemical adaptations
- Keywords
- nitrogen dilution, high humidity, measurement error, respiratory gas analysis
- MeSH terms
- Animals, Dogs, Humidity, Mathematics, Methods, Nitrogen, Oxygen Consumption
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