The impact of submaximal exercise during heat and-or hypoxia on the cardiovascular and monocyte HSP72 responses to subsequent post 24 h exercise in hypoxia Report as inadecuate

The impact of submaximal exercise during heat and-or hypoxia on the cardiovascular and monocyte HSP72 responses to subsequent post 24 h exercise in hypoxia - Download this document for free, or read online. Document in PDF available to download.

Extreme Physiology and Medicine

, 3:15

First Online: 29 September 2014Received: 14 April 2014Accepted: 21 August 2014


BackgroundThe aims of this study were to describe the cellular stress response to prolonged endurance exercise in acute heat, hypoxia and the combination of heat and hypoxia and to determine whether prior acute exposure to these stressors improved cellular tolerance to a subsequent exercise bout in hypoxia 24 h later.

MethodsTwelve males age 22 ± 4 years, height 1.77 ± 0.05 m, mass 79 ± 12.9 kg, VO2 max 3.57 ± 0.7 L · min completed four trials 30-min rest, 90-min cycling at 50% normoxic VO2 max in normothermic normoxia NORM; 18°C, FIO2 = 0.21, heat HEAT; 40°C, 20% RH, hypoxia HYP; FIO2 = 0.14 or a combination of heat and hypoxia COM; 40°C, 20% RH, FIO2 = 0.14 separated by at least 7 days. Twenty-four hours after each trial, participants completed a hypoxic stress test HST; 15-min rest, 60-min cycling at 50% normoxic VO2 max, FIO2 = 0.14. Monocyte heat shock protein 72 mHSP72 was assessed immediately before and after each exercise bout.

ResultsmHSP72 increased post exercise in NORM 107% ± 5.5%, p > 0.05, HYP 126% ± 16%, p < 0.01, HEAT 153% ± 14%, p < 0.01 and COM 161% ± 32%, p < 0.01. mHSP72 had returned to near-resting values 24 h after NORM 97% ± 8.6% but was elevated after HEAT 130% ± 19%, HYP 118% ± 17% and COM 131% ± 19% p < 0.05. mHSP72 increased from baseline after HSTNORM 118% ± 12%, p < 0.05, but did not increase further in HSTHEAT, HSTHYP and HSTCOM.

ConclusionsThe prior induction of mHSP72 as a result of COM, HEAT and HYP attenuated further mHSP72 induction after HST and was indicative of conferred cellular tolerance.

KeywordsCross-acclimation Preconditioning Humans Cycling AbbreviationsANSAutonomic nervous system

a ‒ v ¯ O 2 Open image in new windowArterial-venous difference

COMCombination of heat and hypoxia exercise trial

EDVEnd diastolic volume

FIO2Fraction of inspired oxygen

HEATHeat exercise trial

HRHeart rate

HSP72Heat shock protein 72

HSFHeat shock factor

HSRHeat shock response

HSTHypoxic stress test

HYPHypoxic exercise trial




mHSP72Monocyte heat shock protein 72

NORMNormoxic and normothermic exercise trial

PVPlasma volume

SpO2Arterial hemoglobin oxygen saturation

UosmoUrine osmolality

TNF-αTumor necrosis factor 1 alpha

USGUrine specific gravity.

Electronic supplementary materialThe online version of this article doi:10.1186-2046-7648-3-15 contains supplementary material, which is available to authorized users.

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Author: Ben J Lee - Emma L Emery-Sinclair - Richard WA Mackenzie - Afthab Hussain - Lee Taylor - Rob S James - C Douglas Thake


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