• 1 Environmental Extremes Laboratory, Centre for Sport and Exercise Science and Medicine (SESAME), University of Brighton, Eastbourne, UK
  • 2 Centre for Human Performance, Exercise and Rehabilitation (CHPER), Brunel University London, London, UK
  • 3 FAME Laboratory, Department of Exercise Science, University of Thessaly, Trikala, Greece
  • 4 Centre for Research and Education in Special Environments, Department of Exercise and Nutrition Sciences, University at Buffalo, Buffalo, NY, USA
Temperature (Austin), 2017;4(3):314-329.
PMID: 28944273 DOI: 10.1080/23328940.2017.1333189


In cool conditions, physiologic markers accurately predict endurance performance, but it is unclear whether thermal strain and perceived thermal strain modify the strength of these relationships. This study examined the relationships between traditional determinants of endurance performance and time to complete a 5-km time trial in the heat. Seventeen club runners completed graded exercise tests (GXT) in hot (GXTHOT; 32°C, 60% RH, 27.2°C WBGT) and cool conditions (GXTCOOL; 13°C, 50% RH, 9.3°C WBGT) to determine maximal oxygen uptake (V̇O2max), running economy (RE), velocity at V̇O2max (vV̇O2max), and running speeds corresponding to the lactate threshold (LT, 2 mmol.l(-1)) and lactate turnpoint (LTP, 4 mmol.l(-1)). Simultaneous multiple linear regression was used to predict 5 km time, using these determinants, indicating neither GXTHOT (R(2) = 0.72) nor GXTCOOL (R(2) = 0.86) predicted performance in the heat as strongly has previously been reported in cool conditions. vV̇O2max was the strongest individual predictor of performance, both when assessed in GXTHOT (r = -0.83) and GXTCOOL (r = -0.90). The GXTs revealed the following correlations for individual predictors in GXTHOT; V̇O2maxr = -0.7, RE r = 0.36, LT r = -0.77, LTP r = -0.78 and in GXTCOOL; V̇O2maxr = -0.67, RE r = 0.62, LT r = -0.79, LTP r = -0.8. These data indicate (i) GXTHOT does not predict 5 km running performance in the heat as strongly as a GXTCOOL, (ii) as in cool conditions, vV̇O2max may best predict running performance in the heat.

* Title and MeSH Headings from MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.