Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
The Effect of Low Ambient Relative Humidity on Physical Performance and Perceptual Responses during Load Carriage
KTH, School of Technology and Health (STH), Environmental Physiology.
KTH, School of Technology and Health (STH), Environmental Physiology.
2017 (English)In: Frontiers in Physiology, ISSN 1664-042X, E-ISSN 1664-042X, Vol. 8, no July, article id 451Article in journal (Refereed) Published
Abstract [en]

Introduction: The study evaluated the effect of low ambient relative humidity on physical performance and perceptual responses during load carriage in a hot environment. Methods: Ten heat-unacclimatized male subjects participated in three 130-min trials, during which they walked on a treadmill, carrying a load of similar to 35 kg, at a speed of 3.2 km.h(-1), with an incident wind at the same velocity and ambient temperature at 45 degrees C. Each trial commenced with a 10-min baseline at 20 degrees C and 50% relative humidity (RH), the subjects transferred to a climatic chamber and commenced their simulated hike, comprising two 50-min walks separated by a 20-min rest period. In two, full protective equipment (FP) trials, RH was 10% (partial pressure of water vapor, p(H20) = 7.2 mmHg) in one (FP10), and 20% (p(H20) = 14.4 mmHg; FP20) in the other. In the control trial, subjects were semi-nude (SN) and carried the equipment in their backpacks; RH was 20%. Measurements included oxygen uptake, ventilation, heart rate, rectal and skin temperatures, heat flux, temperature perception, and thermal comfort. Results: In FP20, four subjects terminated the trial prematurely due to signs of heat exhaustion; there were no such signs in FP10 or SN. Upon completion of the trials, pulmonary ventilation, heart rate, and rectal temperature were lower in FP10 (33 5 I/min; 128 +/- 21 bpm; 38.2 +/- 0.4 degrees C) and SN (34 4 I/min; 113 +/- 18 bpm; 38.1 +/- 0.4 degrees C than in FP20 (39 +/- 8 l/min; 145 +/- 12 bpm; 38.6 +/- 0.42 degrees C). Evaporation was significantly greater in the SN compared to FPI and FP20 trials. FP10 was rated thermally more comfortable than FP20. Conclusion: A lower ambient partial pressure of water vapor, reflected in a lower ambient relative humidity, improved cardiorespiratory, thermoregulatory, and perceptual responses during load carriage.

Place, publisher, year, edition, pages
Frontiers Media S.A., 2017. Vol. 8, no July, article id 451
Keywords [en]
ambient relative humidity, evaporative cooling, desert conditions
National Category
Physiology
Identifiers
URN: urn:nbn:se:kth:diva-211343DOI: 10.3389/fphys.2017.00451ISI: 000404880600001Scopus ID: 2-s2.0-85025481393OAI: oai:DiVA.org:kth-211343DiVA, id: diva2:1129092
Funder
EU, Horizon 2020, 668786
Note

QC 20170801

Available from: 2017-08-01 Created: 2017-08-01 Last updated: 2018-01-13Bibliographically approved

Open Access in DiVA

No full text in DiVA

Other links

Publisher's full textScopus

Search in DiVA

By author/editor
Grönkvist, MikaelEiken, Ola
By organisation
Environmental Physiology
In the same journal
Frontiers in Physiology
Physiology

Search outside of DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 10 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf