European Journal of Applied Physiology

, Volume 98, Issue 1, pp 97–104 | Cite as

Body cooling attenuates the decrease in maximal oxygen uptake associated with cardiovascular drift during heat stress

Original Article

Abstract

Previous research suggests cardiovascular drift (CV drift) is associated with decreased maximal oxygen uptake \(\left( \dot{\hbox{V}}\hbox{O}_{\rm 2max} \right)\) during heat stress, but more research manipulating CV drift with subsequent measurement of \(\dot{\hbox{V}}\hbox{O}_{\rm 2max}\) is needed to assess whether this relationship is causal. To assess causation, \(\dot{\hbox{V}}\hbox{O}_{\rm 2max}\) was measured during the same time interval that CV drift occurred (between 15 and 45 min of submaximal exercise under different conditions of body cooling intended to manipulate CV drift). Ten men completed a control graded exercise test (GXT) in 22°C to measure \(\dot{\hbox{V}}\hbox{O}_{\rm 2max},\) then on separate occasions they cycled in 35°C at 60% \(\dot{\hbox{V}}\hbox{O}_{\rm 2max}\) for 15 min (15max), 45 min with no cooling (NC), and 45 min with fan airflow (FAN) beginning at ∼18 min into exercise, and each bout was immediately followed by a GXT to measure \(\dot{\hbox{V}}\hbox{O}_{\rm 2max}. \) In NC, \( \dot{\hbox{V}}\hbox{O}_{\rm 2max} \) decreased 18%, heart rate (HR) increased 16%, and stroke volume (SV) fell 12% (P < 0.05) from min 15 to min 45. In FAN, \(\dot{\hbox{V}}\hbox{O}_{\rm 2max}\) fell less (5.7%, P < 0.05) , HR rose less (4%, P < 0.05) and SV decreased less (3%, P < 0.05) from 15 to 45 min. The fall in \(\dot{\hbox{V}}\hbox{O}_{\rm 2max}\) associated with CV drift during exercise in a hot environment is attenuated with body cooling via fan airflow. The findings support the notion that a causal link exists between CV drift that occurs during prolonged exercise in a hot environment and a decrease in \(\dot{\hbox{V}}\hbox{O}_{\rm 2max}.\)

Keywords

Thermoregulation Heart rate Stroke volume Circulation \(\dot{\hbox{V}}\hbox{O}_{\rm 2max}\) 

References

  1. American College of Sports Medicine (2000) ACSM′s guidelines for exercise testing and prescription. Lippincott, Williams, and Wilkins, BaltimoreGoogle Scholar
  2. Arngrimsson SA, Stewart DJ, Borrani F, Skinner KA, Cureton KJ (2004) Hyperthermia and maximal oxygen uptake in men and women. Eur J Appl Physiol 92:524–532PubMedCrossRefGoogle Scholar
  3. Baum E, Bruck K, Schwennicke HP (1976) Adaptive modifications in thermoregulatory system of long-distance runners. J Appl Physiol 40:404–410PubMedGoogle Scholar
  4. Borg GA (1974) Perceived exertion. Exerc Sport Sci Rev 2:131–153PubMedCrossRefGoogle Scholar
  5. Coyle EF (2002) Cardiovascular drift during prolonged exercise. In: Nose H, Spriet LL, Imwold CH (eds) Exercise, nutrition and environmental stress. Cooper Publishing Company, Traverse City, pp 153–172Google Scholar
  6. Dill DB, Costill DL (1974) Calculation of percentage changes in volumes of red blood cells and plasma in dehydration. J Appl Physiol 37:247–248PubMedGoogle Scholar
  7. Ekblom B (1970) Effect of physical training on circulation during prolonged severe exercise. Acta Physiol Scand 78:145–158PubMedCrossRefGoogle Scholar
  8. Ekelund LG (1966) Circulatory and respiratory adaptation during prolonged exercise in the supine position. Acta Physiol Scand 68:382–396Google Scholar
  9. Fritzsche RG, Switzer TW, Hodgkinson BJ, Coyle EF (1999) Stroke volume decline during prolonged exercise is influenced by the increase in heart rate. J Appl Physiol 86:799–805PubMedGoogle Scholar
  10. Ganio MS, Wingo JE, Carroll CE, Thomas MK, Cureton KJ (2006) Fluid ingestion attenuates the decline in VO2peak associated with cardiovascular drift. Med Sci Sports Exerc 38:901–909PubMedCrossRefGoogle Scholar
  11. Gonzalez-Alonso J, Calbet JAL (2003) Reductions in systemic and skeletal muscle blood flow and oxygen delivery limit maximal aerobic capacity in humans. Circulation 107:824–830PubMedCrossRefGoogle Scholar
  12. Hochberg Y (1988) A sharper Bonferroni procedure for multiple tests of significance. Biometrika 75:800–802CrossRefGoogle Scholar
  13. Johnson JM, Rowell LB (1975) Forearm skin and muscle vascular responses to prolonged leg exercise in man. J Appl Physiol 39:920–924PubMedGoogle Scholar
  14. Jones NL, Campbell EJ, Edwards RH, Robertson DGE (1975) Clinical exercise testing. W.B. Saunders Company, PhiladelphiaGoogle Scholar
  15. Mitchell D, Wyndham CH (1969) Comparison of weighting formulas for calculating mean skin temperature. J Appl Physiol 26:616–622PubMedGoogle Scholar
  16. Montain SJ, Coyle EF (1992) Influence of graded dehydration on hyperthermia and cardiovascular drift during exercise. J Appl Physiol 73:1340–1350PubMedGoogle Scholar
  17. Mortensen SP, Dawson EA, Yoshiga CC, Dalsgaard MK, Damsgaard R, Secher NH, Gonzalez-Alonso J (2005) Limitations to systemic and locomotor limb muscle oxygen delivery and uptake during maximal exercise in humans. J Physiol 566.1:273–285PubMedCrossRefGoogle Scholar
  18. Nybo L, Jensen T, Nielsen B, Gonzalez-Alonso J (2001) Effects of marked hyperthermia with and without dehydration on VO2 kinetics during intense exercise. J Appl Physiol 90:1057–1064PubMedGoogle Scholar
  19. Park I, Schutz RW (1999) “Quick and easy” forumulae for approximating statistical power in repeated measures ANOVA. Meas Phys Educ Exerc Sci 3:249–270CrossRefGoogle Scholar
  20. Potvin PJ, Schutz RW (2000) Statistical power for the two-factor repeated measures ANOVA. Behav Res Methods Instrum Comput 32:347–356PubMedGoogle Scholar
  21. Ramanathan NL (1964) A new weighting system for mean surface temperature of the human body. J Appl Physiol 19(3):531–533PubMedGoogle Scholar
  22. Rowell LB (1974) Human cardiovascular adjustments to exercise and thermal stress. Physiol Rev 54:75–159PubMedGoogle Scholar
  23. Rowell LB, Marx HJ, Bruce RJ, Conn RD, Kusumi F (1966) Reductions in cardiac output, central blood volume, and stroke volume with thermal stress in normal men during exercise. J Clin Invest 45:1801–1816PubMedCrossRefGoogle Scholar
  24. Saltin B, Stenberg J (1964) Circulatory response to prolonged severe exercise. J Appl Physiol 19:833–838PubMedGoogle Scholar
  25. Shaffrath JD, Adams WC (1984) Effects of airflow and work load on cardiovascular drift and skin blood flow. J Appl Physiol 56:1411–1417PubMedGoogle Scholar
  26. Taylor HL, Buskirk E, Henschel A (1955) Maximal oxygen intake as an objective measure of cardio-respiratory performance. J Appl Physiol 8:73–80PubMedGoogle Scholar
  27. Williams CG, Bredell GAG, Wyndham CH, Strydom NB, Morrison JF, Peter J, Fleming PW, Ward JS (1962) Circulatory and metabolic reactions to work in heat. J Appl Physiol 17:625–638PubMedGoogle Scholar
  28. Wingo JE, Cureton KJ (2006) Maximal oxygen uptake after attenuation of cardiovascular drift during heat stress. Aviat Space Environ Med 77:687–694PubMedGoogle Scholar
  29. Wingo JE, Lafrenz AJ, Ganio MS, Cureton KJ (2005a) Effect of cardiovascular drift on maximal oxygen uptake at two ambient temperatures. Med Sci Sports Exerc 37:S169CrossRefGoogle Scholar
  30. Wingo JE, Lafrenz AJ, Ganio MS, Edwards GL, Cureton KJ (2005b) Cardiovascular drift is related to reduced maximal oxygen uptake during heat stress. Med Sci Sports Exerc 37:248–255PubMedCrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2006

Authors and Affiliations

  1. 1.Department of KinesiologyUniversity of GeorgiaAthensUSA

Personalised recommendations