• Novel intervention to confer cellular tolerance: applications & mechanisms

      Tuttle, James A. (University of BedfordshireUniversity of Bedfordshire, 2014-11)
      Exercise in hot environments decreases the temperature gradient for heat loss to the external environment increasing internal heat storage. Work completed decreases and exertional heat illness risk increases. Heat acclimation (HA) programmes which last between 7 -10 d improve heat tolerance by reducing rectal temperature (Tre) during exercise. Thermotolerance is also improved. These adaptations enable work to be maintained for longer periods of time. Exertional heat illness risk is also decreased. However, HA is not logistically feasible during rapid redeployment of military, athletic, occupational and emergency worker populations to hot environments. Therefore, developing an acute preconditioning trial to enhance heat tolerance and thermotolerance could be advantageous. This thesis first determined the effect of treadmill gradient (flat or downhill running) and environmental conditions (temperate~ 20oe, 50 % relative humidity (RH) or hot conditions; 30°C, 50 % RH) on heat shock protein 72 mRNA (Hsp72 mRNA), heat shock protein 90 alpha mRNA (Hsp90a mRNA), glucose regulated protein 78 mRNA, glucose regulate protein 94 mRNA, exercising Tre and HR, Study 2 investigated whether an acute trial combining downhill running and hot environmental conditions (Hot downhill) elevated basal HSP72 concentrations, attenuated exercising Tre• HR, vastus lateralis (VL) and leukocyte Hsp72 mRNA and Hsp90a mRNA responses during an identical trial 7 d later. Downhill running and hot environmental conditions increased leukocyte Hsp72 mRNA, leukocyte Hsp90a mRNA, exercising Trc and DOMS further than flat running and temperate environmental conditions. Increased Hsp72 mRNA and Hsp90a mRNA were mainly exercising Tre and metabolic strain dependent. Exercising Tn; (at 30 min) and DOMS were reduced during or following the second hot downhill trial. Attenuated Hsp72 mRNA and Hsp90a mRNA responses within the VL and leukocytes also occurred. Basal VL HSP72 increased after the second hot downhill trial In conclusion, an acute hot downhill trial decreases exercising Tn: and DOMS during an identical trial 7 d later but basal HSP72 concentrations are not affected. Leukocyte Hsp72 mRNA and Hsp90a mRNA are valid surrogates of the VL response.