European Journal of Applied Physiology

, Volume 94, Issue 3, pp 228–234 | Cite as

Reliability of peak \(\dot V{\text{O}}_2 \) and maximal cardiac output assessed using thoracic bioimpedance in children

  • Joanne Welsman
  • Katie Bywater
  • Colin Farr
  • Deborah Welford
  • Neil Armstrong
Original Article


The purpose of this study was to evaluate the reliability of a thoracic electrical bioimpedance based device (PhysioFlow) for the determination of cardiac output and stroke volume during exercise at peak oxygen uptake (peak \(\dot V{\text{O}}_2 \) in children. The reliability of peak \(\dot V{\text{O}}_2 \) is also reported. Eleven boys and nine girls aged 10–11 years completed a cycle ergometer test to voluntary exhaustion on three occasions each 1 week apart. Peak \(\dot V{\text{O}}_2 \) was determined and cardiac output and stroke volume at peak \(\dot V{\text{O}}_2 \) were measured using a thoracic bioelectrical impedance device (PhysioFlow). The reliability of peak \(\dot V{\text{O}}_2 ,\) cardiac output and stroke volume were determined initially from pairwise comparisons and subsequently across all three trials analysed together through calculation of typical error and intraclass correlation. The pairwise comparisons revealed no consistent bias across tests for all three measures and there was no evidence of non-uniform errors (heteroscedasticity). When three trials were analysed together typical error expressed as a coefficient of variation was 4.1% for peak \(\dot V{\text{O}}_2 ,\) 9.3% for cardiac output and 9.3% for stroke volume. Results analysed by sex revealed no consistent differences. The PhysioFlow method allows non-invasive, beat-to-beat determination of cardiac output and stroke volume which is feasible for measurements during maximal exercise in children. The reliability of the PhysioFlow falls between that demonstrated for Doppler echocardiography (5%) and CO2 rebreathing (12%) at maximal exercise but combines the significant advantages of portability, lower expense and requires less technical expertise to obtain reliable results.


Stroke volume Exercise PhysioFlow 


  1. Armstrong N, Welsman JR (1994) The assessment and interpretation of aerobic fitness in children. Exerc Sport Sci Rev 22:435–476Google Scholar
  2. Armstrong N, Welsman JR (2000) Aerobic fitness. In: Armstrong N, Van Mechelen W (eds) Paediatric exercise science and medicine. Oxford University Press, Oxford, pp 173–182Google Scholar
  3. Atkinson G, Nevill AM (1998) Statistical methods for assessing measurement error (reliability) in variables relevant to sports medicine. Sports Med 26:217–238PubMedGoogle Scholar
  4. Atkinson G, Nevill A (2000) Typical error versus limits of agreement. Sports Med 30:375–381Google Scholar
  5. Berstein DP (1986) A new stroke volume equation for thoracic bioimpedance: theory and rationale. Crit Care Med 14:904–909Google Scholar
  6. Bland JM, Altman DG (1986) Statistical methods for assessing agreement between two methods of clinical measurement. Lancet Feb 8:307–310Google Scholar
  7. Charloux A, Lonsdorfer-Wolf E, Richard R, Lampert E, Oswald-Mamosser M, Mettauer B, Geny B, Lonsdorfer J (2000) A new impedance cardiograph device for the non-invasive evaluation of cardiac output at rest and during exercise: comparison with the “direct” Fick method. Eur J Appl Physiol 82:313–320CrossRefPubMedGoogle Scholar
  8. Driscoll DJ, Staats BA, Beck KC (1989) Measurement of cardiac output in children during exercise: a review. Pediatr Exerc Sci 1:102–115Google Scholar
  9. Espersen K, Jensen EW, Rosenborg D, Thomsen JK, Eliasen K, Olsen NV, Kanstrup I-L (1995) Comparison of cardiac output measurement techniques: thermodilution, Doppler, CO2-rebreathing and the direct Fick method. Acta Anaesth Scand 39:245–251Google Scholar
  10. Ferguson RJ, Faulkner JA, Julius S, Conway J (1968) Comparison of cardiac output determined by CO2 rebreathing and dye-dilution methods. J Appl Physiol 25:450–454Google Scholar
  11. Figuera-Colon R, Hunter GR, Mayo MS, Aldredge RA, Goran MI, Weinsier RL (2000) Reliability of treadmill measures and criteria to determine VO2 max in prepubertal girls. Med Sci Sports Exerc 32:865–869CrossRefGoogle Scholar
  12. Haycock, GB, Schwartz GJ, Wisotsky DH (1978) Geometric method for measuring body surface area: a height–weight formula validated in infants, children and adults. J Pediatr 93:62–66Google Scholar
  13. Hopkins WG (2000) Measures of reliability in sports medicine and science. Sports Med 30:1–15Google Scholar
  14. Katch VL, Sady SS, Freedson P (1982) Biological variability in maximum aerobic power. Med Sci Sports Exerc 14:21–25Google Scholar
  15. Kubicek WG, Karnegis JN, Patterson RP, Witsoe DA, Mattson RH (1966) Development and evaluation of an impedance cardiac output system. Aerosp Med 37:1208–1212Google Scholar
  16. Nottin S, Vinet A, Lecoq A-M, Guenon P, Obert P (2001) Test–retest reproducibility of submaximal and maximal cardiac output by Doppler Echocardiography and CO2-rebreathing in prepubertal children. Pediatr Exerc Sci 13:214–224Google Scholar
  17. Paterson DH, Cunningham DA, Plyley MJ, Blimkie CJR, Donner D (1982) The consistency of cardiac output measurement (CO2 rebreathe) in children during exercise. Eur J Appl Physiol 49:37–44CrossRefGoogle Scholar
  18. Pianosi PT (2004) Measurement of exercise cardiac output by thoracic impedance in healthy children. Eur J Appl Physiol 92:425–430CrossRefGoogle Scholar
  19. Pianosi P, Garros D (1996) Comparison of impedance cardiography with indirect Fick (CO2) method of measuring cardiac output in healthy children during exercise. Am J Cardiol 77:745–749Google Scholar
  20. Pivarnik JM, Dwyer MC, Lauderdale MA (1996) The reliability of aerobic capacity (VO2 max) testing in adolescent girls. Res Q Exerc Sport 67:345–348Google Scholar
  21. Richard RE, Lonsdorfer-Wolf E, Charloux A, Doutreleau S, Buchheit M, Oswald-Mammosser M, Lampert E, Mettauer B, Geny B, Lonsdorfer J (2001) Non-invasive cardiac output evaluation during a maximal progressive exercise test, using a new impedance cardiograph device. Eur J Appl Physiol 85:202–207CrossRefPubMedGoogle Scholar
  22. Rivera-Brown AM, Frontera WR (1998) Achievement of plateau and reliability of VO2 max in trained adolescents tested with different ergometers. Pediatr Exerc Sci 10:164–175Google Scholar
  23. Rivera-Brown AM, Rivera MA, Frontera WR (1995) Reliability of VO2 max in adolescent runners: a comparison between plateau achievers and nonachievers. Pediatr Exerc Sci 7:203–210Google Scholar
  24. Rowland T (1996) Developmental exercise physiology. Human Kinetics, Champaign, ILGoogle Scholar
  25. Rowland T, Blum JW (2000) Cardiac dynamics during upright cycle exercise in boys. Am J Hum Biol 12:749–757Google Scholar
  26. Rowland T, Obert P (2002) Doppler echocardiography for the estimation of cardiac output with exercise. Sports Med 32:973–986Google Scholar
  27. Rowland TW, Popowski B (1996) Comparison of bioimpedance and Doppler cardiac output during exercise in children. Pediatr Exerc Sci 9:188–189Google Scholar
  28. Rowland T, Popowski B, Ferrone L (1997) Cardiac responses to maximal upright cycle exercise in healthy boys and men. Med Sci Sports Exerc 29:1146–1151Google Scholar
  29. Rowland TW, Melanson EL, Popowski BE, Ferrone LC (1998) Test-retest reproducibility of maximum cardiac output by Doppler echocardiography. Am J Cardiol 81:1228–1230Google Scholar
  30. Sramek BB (1982) Cardiac output by electrical impedance. Med Electron 13:93–97Google Scholar
  31. Turley KR, Rogers DM, Harper KM, Kujawa KI, Wilmore JH (1995) Maximal treadmill versus cycle ergometry testing in children: differences, reliability and variability of responses. Pediatr Exerc Sci 7:49–60Google Scholar
  32. Vinet A, Nottin S, Lecoq A-M, Guenon P, Obert P (2001) Reproducibility of cardiac output measurements by Doppler echocardiography in prepubertal children and adults. Int J Sports Med 22:437–441CrossRefGoogle Scholar
  33. Warburton, DER, Gledhill N, Jamnik VK (1998) Reproducibility of the acetylene rebreathe technique for determining cardiac output. Med Sci Sports Exerc 30:952–957CrossRefGoogle Scholar
  34. Warburton, DER, Haykowsky MJF, Quinney HA, Humen DP, Teo KK (1999a) Reliability and validity of measures of cardiac output during incremental to maximal aerobic exercise. Part I: Conventional techniques. Sports Med 27:23–41PubMedGoogle Scholar
  35. Warburton DER, Haykowsky MJF, Quinney HA, Humen DP, Teo KK (1999b) Reliability and validity of measures of cardiac output during incremental to maximal aerobic exercise. Part II: Novel techniques and new advances. Sports Med 27:241–260PubMedGoogle Scholar
  36. Zeidifard E, Silverman M, Godfrey S (1972) Reproducibility of indirect (CO2) Fick method for calculation of cardiac output. J Appl Physiol 33: 141–143Google Scholar

Copyright information

© Springer-Verlag 2005

Authors and Affiliations

  • Joanne Welsman
    • 1
  • Katie Bywater
    • 1
  • Colin Farr
    • 1
  • Deborah Welford
    • 1
  • Neil Armstrong
    • 1
  1. 1.Children’s Health and Exercise Research CentreUniversity of ExeterExeterUK

Personalised recommendations