Sauna, sweat and science – quantifying the proportion of condensation water versus sweat using a stable water isotope (2H/1H and 18O/16O) tracer experiment

Research output: Contribution to journalResearch articleContributedpeer-review


  • Michael Zech - , Heisenberg Chair of Physical Geography with a Focus on Paleoenvironmental Research, University of Bayreuth, Martin Luther University Halle-Wittenberg (Author)
  • Stefanie Bösel - , Thermo Fisher Scientific, Inc. (Author)
  • Mario Tuthorn - , University of Bayreuth (Author)
  • Marianne Benesch - , Martin Luther University Halle-Wittenberg (Author)
  • Maren Dubbert - , University of Bayreuth (Author)
  • Matthias Cuntz - , Helmholtz Centre for Environmental Research (Author)
  • Bruno Glaser - , Martin Luther University Halle-Wittenberg (Author)


Most visitors of a sauna appreciate the heat pulse that is perceived when water is poured on the stones of a sauna stove. However, probably only few bathers are aware that this pleasant heat pulse is caused by latent heat being released onto our skin due to condensation of water vapour. In order to quantify the proportion of condensation water versus sweat to dripping water of test persons we conducted sauna experiments using isotopically labelled (δ18O and δ2H) thrown water as tracer. This allows differentiating between ‘pure sweat’ and ‘condensation water’. Two ways of isotope mass balance calculations were applied and yielded similar results for both water isotopes. Accordingly, condensation contributed considerably to dripping water with mean proportions of 52 ± 12 and 54 ± 7 % in a sauna experiment in winter semester 2011/12 and 30 ± 13 and 33 ± 6 % in a sauna experiment in winter semester 2012/13, respectively, depending on the way of calculating the isotope mass balance. It can be concluded from the results of our dual isotope labelling sauna experiment that it is not all about sweat in the sauna.


Original languageEnglish
Pages (from-to)439-447
Number of pages9
JournalIsotopes in environmental and health studies
Issue number3
Publication statusPublished - 3 Jul 2015

External IDs

PubMed 26110629



  • condensation, hydrogen-2, isotope labelling, oxygen-18, perspiration, phase transition, sauna, tracer