2134/17344 James A. Tuttle James A. Tuttle Paul C. Castle Paul C. Castle Alan J. Metcalfe Alan J. Metcalfe Adrian W. Midgley Adrian W. Midgley Lee Taylor Lee Taylor Mark Lewis Mark Lewis Downhill running and exercise in hot environments increase leukocyte Hsp 72 (HSPA1A) and Hsp90α (HSPC1) gene transcripts Loughborough University 2015 Heat shock response Exercise heat stress Thermotolerance Medical and Health Sciences not elsewhere classified 2015-04-22 15:03:16 Journal contribution https://repository.lboro.ac.uk/articles/journal_contribution/Downhill_running_and_exercise_in_hot_environments_increase_leukocyte_Hsp_72_HSPA1A_and_Hsp90_HSPC1_gene_transcripts/9611861 Stressors within humans and other species activate Hsp72 and Hsp90α mRNA transcription, although it is unclear which environmental temperature or treadmill gradient induces the largest increase. To determine the optimal stressor for priming the Hsp system, physically active but not heat-acclimated participants (19.8 ± 1.9 and 20.9 ± 3.6 yr) exercised at lactate threshold in either temperate (20°C, 50% relative humidity; RH) or hot (30°C, 50% RH) environmental conditions. Within each condition, participants completed a flat running (temperate flat or hot flat) and a downhill running (temperate downhill or hot downhill) experimental trial in a randomized counterbalanced order separated by at least 7 days. Venous blood samples were taken immediately before (basal), immediately after exercise, and 3 and 24 h postexercise. RNA was extracted from leukocytes and RT-quantitative PCR conducted to determine Hsp72 and Hsp90α mRNA relative expression. Leukocyte Hsp72 mRNA was increased immediately after exercise following downhill running (1.9 ± 0.9-fold) compared with flat running (1.3 ± 0.4-fold; P = 0.001) and in hot (1.9 ± 0.6-fold) compared with temperate conditions (1.1 ± 0.5-fold; P = 0.003). Leukocyte Hsp90α mRNA increased immediately after exercise following downhill running (1.4 ± 0.8-fold) compared with flat running (0.9 ± 0.6-fold; P = 0.002) and in hot (1.6 ± 1.0-fold) compared with temperate conditions (0.9 ± 0.6-fold; P = 0.003). Downhill running and exercise in hot conditions induced the largest stimuli for leukocyte Hsp72 and Hsp90α mRNA increases.