European Journal of Applied Physiology

, Volume 104, Issue 2, pp 321–327 | Cite as

Lowering of resting core temperature during acclimation is influenced by exercise stimulus

  • Bernhard Kampmann
  • Peter Bröde
  • Martin Schütte
  • Barbara Griefahn
Original Article


The decrease in resting core temperature (T co) and its relation to the reduced physiological strain during heat acclimation was analysed with rectal temperature data measured in three groups of eight semi-nude persons (6 males, 2 females) who were acclimated for 15 consecutive days to dry, humid and radiant heat, respectively, with equivalent WBGT (33.5°C), by performing 2-h treadmill work. A fourth group followed the same protocol for 12 days in a neutral climate. After acclimation, both resting T co, prior to heat exposure, and final T co, measured at the end of work, were significantly reduced. The reduction in final T co increased with decreasing ambient water vapour pressure and was higher for the data pooled over the heat conditions (0.46 ± 0.31°C) than in the neutral climate (0.21 ± 0.25°C), whereas resting T co declined similarly in the heat (0.20 ± 0.25°C) and the neutral environment (0.17 ± 0.23°C). The lowering of resting and final T co after heat acclimation showed a significant correlation (r = 0.67) and regression analysis showed that 37% of the average reduction in final T co was attributable to the lowering of resting T co. The same analysis was applied after extending the database by short-term series of clothed persons (17 females, 16 males) acclimated at 29.5 and 31.5°C WBGT for 5 days. A significant correlation was found between the lowering of resting and final T co (r = 0.57) that did not depend on climatic conditions and gender, although the reduction in resting T co was significantly smaller for females (0.06 ± 0.22°C) than for males (0.21 ± 0.23°C). It is concluded that the lowering of resting core temperature contributes to the reduced physiological strain during heat acclimation. Similar effects under neutral conditions point to the exercise stimulus as a probable explanation.


Acclimation Heat stress Exercise Resting core temperature Rectal temperature Gender 


  1. Aoyagi Y, McLellan TM, Shephard RJ (1997) Interactions of physical training and heat acclimation. The thermophysiology of exercising in a hot climate. Sports Med 23:173–210PubMedCrossRefGoogle Scholar
  2. Avellini BA, Kamon E, Krajewski JT (1980) Physiological responses of physically fit men and women to acclimation to humid heat. J Appl Physiol 49:254–261PubMedGoogle Scholar
  3. Buono MJ, Heaney JH, Canine KM (1998) Acclimation to humid heat lowers resting core temperature. Am J Physiol Regul Integr Comp Physiol 274:R1295–R1299Google Scholar
  4. Cheung SS, McLellan TM (1998) Heat acclimation, aerobic fitness, and hydration effects on tolerance during uncompensable heat stress. J Appl Physiol 84:1731–1739PubMedGoogle Scholar
  5. Cotter JD, Patterson MJ, Taylor NAS (1997) Sweat distribution before and after repeated heat exposure. Eur J Appl Physiol 76:181–186CrossRefGoogle Scholar
  6. Fox RH, Goldsmith R, Kidd DJ, Lewis HE (1963) Blood flow and other thermoregulatory changes with acclimatization to heat. J Physiol 166:548–562PubMedGoogle Scholar
  7. Frye AJ, Kamon E, Webb M (1982) Responses of menstrual women, amenorrheal women, and men to exercise in a hot, dry environment. Eur J Appl Physiol 48:279–288CrossRefGoogle Scholar
  8. Givoni B, Goldman RF (1972) Predicting rectal temperature response to work, environment, and clothing. J Appl Physiol 32:812–822PubMedGoogle Scholar
  9. Givoni B, Goldman RF (1973) Predicting effects of heat acclimatization on heart rate and rectal temperature. J Appl Physiol 35:875–879PubMedGoogle Scholar
  10. Gonzalez RR, McLellan TM, Withey WR, Chang SK, Pandolf KB (1997) Heat strain models applicable for protective clothing systems: comparison of core temperature response. J Appl Physiol 83:1017–1032PubMedGoogle Scholar
  11. Griefahn B (1997) Acclimation to three different hot climates with equivalent wet bulb globe temperatures. Ergonomics 40:223–234PubMedCrossRefGoogle Scholar
  12. Grucza R, Pekkarinen H, Titov EK, Kononoff A, Hänninen O (1993) Influence of the menstrual cycle and oral contraceptives on thermoregulatory responses to exercise in young women. Eur J Appl Physiol 67:279–285CrossRefGoogle Scholar
  13. Havenith G, van Middendorp H (1990) The relative influence of physical fitness, acclimatization state, anthropometric measures and gender on individual reactions to heat stress. Eur J Appl Physiol 61:419–427CrossRefGoogle Scholar
  14. Höfler W (1966) Verlauf der Hitzeakklimatisation in einem natürlichen tropischen Klima. Z Tropenmed Parasitol 17:127–144PubMedGoogle Scholar
  15. Höfler W, Ladipoh J, Laaser U (1969) Beziehung zwischen Schweißmenge, Verdunstung und Körpertemperatur bei der Akklimatisation in künstlichem feuchtheißen Klima. Int Z Angew Physiol 27:34–42PubMedGoogle Scholar
  16. Huber PJ (1973) Robust regression: asymptotics, conjectures and Monte Carlo. Ann Stat 1:799–821CrossRefGoogle Scholar
  17. ISO 7933 (2004) Ergonomics of the thermal environment—analytical determination and interpretation of heat stress using calculation of the predicted heat strain. International Organisation for Standardisation, GenevaGoogle Scholar
  18. Kobayashi Y, Ando Y, Takeuchi S, Takemura K, Okuda N, Isobe Y, Takaba S, Ohara K (1980) Effects of heat acclimation of distance runners in a moderately hot environment. Eur J Appl Physiol 45:189–198CrossRefGoogle Scholar
  19. Littell RC, Milliken GA, Stroup WW, Wolfinger RD (1996) SAS® system for mixed models. SAS® Institute, CaryGoogle Scholar
  20. Nielsen B, Hales JRS, Strange S, Christensen NJ, Warberg J, Saltin B (1993) Human circulatory and thermoregulatory adaptations with heat acclimation and exercise in a hot, dry environment. J Physiol 460:467–485PubMedGoogle Scholar
  21. Orenstein DM, Henke KG, Green CG (1984) Heat acclimation in cystic fibrosis. J Appl Physiol 57:408–412PubMedGoogle Scholar
  22. Pandolf KB (1979) Effects of physical training and cardiorespiratory physical fitness on exercise-heat tolerance: recent observations. Med Sci Sports 11:60–65PubMedGoogle Scholar
  23. Patterson MJ, Stocks JM, Taylor NAS (2004) Humid heat acclimation does not elicit a preferential sweat redistribution toward the limbs. Am J Physiol Regul Integr Comp Physiol 286:R512–R518PubMedGoogle Scholar
  24. Rogers SM, Baker MA (1997) Thermoregulation during exercise in women who are taking oral contraceptives. Eur J Appl Physiol 75:34–38CrossRefGoogle Scholar
  25. Schütte M, Kampmann B (2005) Acclimation and resting core-temperature. In: Bust PD, McCabe PT (eds) Contemporary ergonomics. Taylor & Francis, London, pp 213–216Google Scholar
  26. Selkirk GA, McLellan TM (2001) Influence of aerobic fitness and body fatness on tolerance to uncompensable heat stress. J Appl Physiol 91:2055–2063PubMedGoogle Scholar
  27. Shido O, Sugimoto N, Tanabe M, Sakurada S (1999) Core temperature and sweating onset in humans acclimated to heat given a fixed daily time. Am J Physiol Regul Integr Comp Physiol 276:R1095–R1101Google Scholar
  28. Shvartz E, Magazanik A, Glick Z (1974) Thermal responses during training in a temperate climate. J Appl Physiol 36:572–576PubMedGoogle Scholar
  29. Shvartz E, Shapiro Y, Magazanik A, Meroz A, Birnfeld H, Mechtinger A, Shibolet S (1977) Heat acclimation, physical fitness, and responses to exercise in temperate and hot environments. J Appl Physiol 43:678–683PubMedGoogle Scholar
  30. Wyndham CH, Strydom NB, Morrison JF, Du Toit FD, Kraan JG (1954) Responses of unacclimatized men under stress of heat and work. J Appl Physiol 6:681–686PubMedGoogle Scholar

Copyright information

© Springer-Verlag 2008

Authors and Affiliations

  • Bernhard Kampmann
    • 1
  • Peter Bröde
    • 2
  • Martin Schütte
    • 2
  • Barbara Griefahn
    • 2
  1. 1.Division of Applied Physiology, Occupational Medicine and Infectiology, Department of Safety EngineeringBergische Universität WuppertalWuppertalGermany
  2. 2.Leibniz Research Centre for Working Environment and Human Factors at the University of Dortmund (IfADo)DortmundGermany

Personalised recommendations