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J Sports Sci Med. 2014 Dec 01;13(4):774-81. eCollection 2014 Dec.

Influence of acute normobaric hypoxia on physiological variables and lactate turn point determination in trained men.

Journal of sports science & medicine

Michael Ofner, Manfred Wonisch, Mario Frei, Gerhard Tschakert, Wolfgang Domej, Julia M Kröpfl, Peter Hofmann

Affiliations

  1. Department of Sport's and Exercise Physiology, University of Vienna , Austria.
  2. Department of Cardiology, Hansa Hospital Graz , Austria.
  3. Institute of Human Movement Sciences and Sport, Exercise Physiology Lab , ETH Zurich, Switzerland ; Human Performance Research, University and Medical University of Graz , Austria.
  4. Division of Pulmonology, Department of Internal Medicine, Medical University of Graz , Austria.

PMID: 25435769 PMCID: PMC4234946

Abstract

The goal of this study is to evaluate the response of physiological variables to acute normobaric hypoxia compared to normoxia and its influence on the lactate turn point determination according to the three-phase model of energy supply (Phase I: metabolically balanced at muscular level; Phase II: metabolically balanced at systemic level; Phase III: not metabolically balanced) during maximal incremental exercise. Ten physically active (VO2max 3.9 [0.49] l·min(-1)), healthy men (mean age [SD]: 25.3 [4.6] yrs.), participated in the study. All participants performed two maximal cycle ergometric exercise tests under normoxic as well as hypoxic conditions (FiO2 = 14%). Blood lactate concentration, heart rate, gas exchange data, and power output at maximum and the first and the second lactate turn point (LTP1, LTP2), the heart rate turn point (HRTP) and the first and the second ventilatory turn point (VETP1, VETP2) were determined. Since in normobaric hypoxia absolute power output (P) was reduced at all reference points (max: 314 / 274 W; LTP2: 218 / 184 W; LTP1: 110 / 96 W), as well as VO2max (max: 3.90 / 3.23 l·min(-1); LTP2: 2.90 / 2.43 l·min(-1); LTP1: 1.66 / 1.52 l·min(-1)), percentages of Pmax at LTP1, LTP2, HRTP and VETP1, VETP2 were almost identical for hypoxic as well as normoxic conditions. Heart rate was significantly reduced at Pmax in hypoxia (max: 190 / 185 bpm), but no significant differences were found at submaximal control points. Blood lactate concentration was not different at maximum, and all reference points in both conditions. Respiratory exchange ratio (RER) (max: 1.28 / 1.08; LTP2: 1.13 / 0.98) and ventilatory equivalents for O2 (max: 43.4 / 34.0; LTP2: 32.1 / 25.4) and CO2 (max: 34.1 / 31.6; LTP2: 29.1 / 26.1) were significantly higher at some reference points in hypoxia. Significant correlations were found between LTP1 and VETP1 (r = 0.778; p < 0.01), LTP2 and HRTP (r = 0.828; p < 0.01) and VETP2 (r = 0.948; p < 0.01) for power output for both conditions. We conclude that the lactate turn point determination according to the three-phase-model of energy supply is valid in normobaric, normoxic as well as hypoxic conditions. The turn points for La, HR, and VE were reproducible among both conditions, but shifted left to lower workloads. The lactate turn point determination may therefore be used for the prescription of exercise performance in both environments. Key PointsThe lactate turn point concept can be used for performance testing in normoxic and hypoxic conditionsThe better the performance of the athletes the higher is the effect of hypoxiaThe HRTP and LTP2 are strongly correlated that allows a simple performance testing using heart rate measures only.

Keywords: Hypoxia; heart rate; performance; spiroergometry; threshold determination

References

  1. Med Sci Sports Exerc. 1986 Jun;18(3):360-8 - PubMed
  2. Int J Sports Med. 2007 Mar;28(3):186-92 - PubMed
  3. J Sports Sci. 1993 Feb;11(1):37-42 - PubMed
  4. Ross Fiziol Zh Im I M Sechenova. 2012 Nov;98 (11):1396-415 - PubMed
  5. Eur J Appl Physiol. 2002 May;87(1):66-71 - PubMed
  6. J Appl Physiol (1985). 2007 Jun;102(6):2399-401; discussion 2401-2 - PubMed
  7. Eur J Appl Physiol Occup Physiol. 1994;69(2):132-9 - PubMed
  8. High Alt Med Biol. 2009 Summer;10 (2):123-34 - PubMed
  9. Int J Sports Med. 1995 Feb;16(2):78-81 - PubMed
  10. Int J Sports Med. 2007 Mar;28(3):181-5 - PubMed
  11. Br J Sports Med. 2012 May;46(6):381-4 - PubMed
  12. Int J Sports Med. 2006 Apr;27(4):301-6 - PubMed
  13. J Appl Physiol (1985). 2012 May;112(10 ):1788-94 - PubMed
  14. J Appl Physiol (1985). 2007 Jun;102(6):2398-9 - PubMed
  15. Eur J Appl Physiol. 2006 Mar;96(4):404-12 - PubMed
  16. Int J Sports Med. 1992 Oct;13 Suppl 1:S76-8 - PubMed
  17. Eur J Appl Physiol. 2001 Jul;85(1-2):82-8 - PubMed
  18. Int Heart J. 2010 May;51(3):170-5 - PubMed
  19. Eur J Appl Physiol. 2004 Mar;91(2-3):296-302 - PubMed
  20. J Appl Physiol (1985). 1988 Apr;64(4):1486-92 - PubMed
  21. Eur J Appl Physiol. 2012 Aug;112(8):3079-86 - PubMed
  22. Aviat Space Environ Med. 2012 Jul;83(7):677-84 - PubMed
  23. Med Sci Sports Exerc. 2004 Oct;36(10 ):1737-42 - PubMed
  24. Int J Sports Med. 1994 Jul;15(5):232-7 - PubMed
  25. Eur J Appl Physiol. 2007 Sep;101(1):67-73 - PubMed
  26. Med Sci Sports Exerc. 1997 Jun;29(6):762-8 - PubMed
  27. Eur J Cardiovasc Prev Rehabil. 2008 Dec;15(6):726-34 - PubMed
  28. Res Q Exerc Sport. 1980 Mar;51(1):234-48 - PubMed
  29. J Physiol. 2003 Jul 15;550(Pt 2):605-16 - PubMed
  30. Am J Physiol Regul Integr Comp Physiol. 2012 Apr 15;302(8):R903-16 - PubMed
  31. J Physiol. 2009 Dec 1;587(Pt 23):5591-600 - PubMed
  32. Aviat Space Environ Med. 2012 Oct;83(10 ):975-84 - PubMed
  33. Eur J Appl Physiol. 2003 Nov;90(5-6):514-9 - PubMed
  34. Med Sci Sports Exerc. 2001 Oct;33(10):1726-31 - PubMed
  35. Cardiol Res Pract. 2010 Dec 15;2011:209302 - PubMed
  36. J Asthma. 2010 Aug;47(6):609-13 - PubMed
  37. Eur J Appl Physiol Occup Physiol. 1993;67(1):7-13 - PubMed
  38. Am J Physiol. 1998 Oct;275(4 Pt 2):R1192-201 - PubMed
  39. Eur J Appl Physiol. 2007 Aug;100(6):663-73 - PubMed
  40. Am J Physiol Regul Integr Comp Physiol. 2003 Feb;284(2):R291-303 - PubMed
  41. Int J Sports Med. 1997 Feb;18(2):101-5 - PubMed
  42. Eur J Appl Physiol. 2014 Aug;114(8):1555-62 - PubMed
  43. Int J Sports Physiol Perform. 2014 Nov;9(6):978-84 - PubMed

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