Water immersion delays the oxygen uptake response to sitting arm-cranking in humans

Naoyuki Hayashi*, Takayoshi Yoshida

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)


We investigated the effect of central hypervolaemia during water immersion up to the xiphoid process on the oxygen uptake (V̇O2) and heart rate (HR) response to arm cranking. Seven men performed a 6-min arm-cranking exercise at an intensity requiring a V̇O2 at 80% ventilatory threshold both in air [C trial, 29 (SD 9) W] and immersed in water [WI trial, 29 (SD 11) W] after 6 min of sitting. The V̇O2 (phase 2) and HR responses to exercise were obtained from a mono-exponential fit [f(t) = baseline + gain·(1 - e(-(t-TD)/Υ))]. The response was evaluated by the mean response time [MRT; sum of time constant (Υ) and time delay (TD)]. No significant difference in V̇O2 and HR gains between the C and WI trials was observed [V̇O2 0.78 (SD 0.1) vs 0.80 (SD 0.2) 1·min-1, HR 36 (SD 7) vs 37 (SD 8) beats·min-1, respectively]. Although the HR MRT was not significantly different between the C and WI trials [17 (SD 3), 19 (SD 8) s, respectively), V̇O2 MRT was greater in the WI trial than in the C trial [40 (SD 6), 45 (SD 6) s, respectively; P < 0.05]. Assuming no difference in V̇O2 in active muscle between the two trials, these results would indicate that an increased oxygen store and/or an altered response in muscle blood distribution delayed the V̇O2 response to exercise.

Original languageEnglish
Pages (from-to)132-138
Number of pages7
JournalEuropean Journal of Applied Physiology and Occupational Physiology
Issue number2
Publication statusPublished - 1999 Jul
Externally publishedYes


  • Cardiac output
  • Central hypervolaemia
  • Heart rate
  • Oxygen store
  • Oxygen uptake kinetics

ASJC Scopus subject areas

  • Physiology
  • Public Health, Environmental and Occupational Health


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