1. Rodríguez, F.A., Iglesias X., Barrero A., Ábalos X.,
Moreno D., Abellán R., Segura J. Intermittent
Hypobaric Hypoxia Exposure increases ventilatory
treshold but not running performance in triathletes.
1st WORLD CONFERENCE OF SCIENCE IN
TRIATHLON. Alacant, 2011.
Sport Sciences Research Group INEFC Barcelona
Grup de Recerca en Ciències de l'Esport INEFC Barcelona
Grup Consolidat (2009 SGR1054)
Institut Nacional d’Educació Física de Catalunya
Av. de l’Estadi, 12-22
08038 Barcelona (Spain)
+34 93 425 54 45 grce@gencat.cat @Recerca_INEFC

2. Intermittent Hypobaric Hypoxia Exposure
Increases Ventilatory Threshold But Not
Running Performance In Triathletes
Rodríguez FA, Iglesias X, Barrero A, Ábalos X,
Moreno D, Abellán R, Segura J
IMAS
Institut Municipal
d’Investigació Mèdica. IMIM
Pharmacology Research Unit

3. Contemporary
Applications of Hypoxia
to Athletic Training
Altitude Training Intermittent Hypoxia
Natural hypobaric hypoxia Artificial hypoxia
at altitude (mountains) (Hypobaric / Normobaric)
LH-TH LH-TL LL-TH IHE IHT IHIT
High-High High-Low Low-High Intermittent Intermittent IH Interval
Hypoxia Hypoxic Training
Exposure Training
LH-THO2
+ Suppl. O2
Rodríguez 2005 ECSS Congress

4. Please see keynote conference by Dr. Randy Wilber
"Training in Altitude“
(12 h)

5. Contemporary
Applications of Hypoxia
to Athletic Training
Altitude Training Intermittent Hypoxia
Natural hypobaric hypoxia Artificial hypoxia
at altitude (mountains) (Hypobaric / Normobaric)
LH-TH LH-TL LL-TH IHE IHT IHIT
High-High High-Low Low-High Intermittent Intermittent IH Interval
Hypoxia Hypoxic Training
Exposure Training
LH-THO2
+ Suppl. O2
Rodríguez 2005 ECSS Congress

6. The short-term IHE model
• Short-term IHE in climbers and endurance athletes
9-21 d, 1.5-5 h/d, 4000-5500 m1-8
• Erythropoietic response
EPO, PCV, retics1-7 but not Hbmass increase8
• Increased VO2max in climbers (+6.2%)1 and swimmers
+5.4%6, +3.3%8, but not in runners8
• Improved performance in middle-distance swimmers
+0.9% in 200-m time6, world-class track cyclists +2.9% in 4’ trial)7
but not in swimmers and runners8
1 Casas et al. 1998 J Sports Sci 5 Rodríguez et al. 2000 Eur J Appl Physiol
2 Casas et al. 2000 Aviat Space Environ Med 6 Rodríguez et al. 2002 IX WSBMS
3 Rodríguez et al. 1998 J Sports Sci 7 Rodríguez et al. 2002 7th ECSS Congress, Athens
4 Rodríguez et al. 1999 Med Sci Sports Exerc 8 Rodríguez et al. 2007 J Appl Physiol

7. Intermittent Hypoxia Study 2003
IHE at hypobaric chamber
Randomized, double blind, placebo controlled study
23 trained athletes (10 runners, 13 swimmers)
3-km and 100/400-m time trial (performance markers)
submax and maximal VO2 (treadmill or flume)
3 h/d, 5 d/wk, 4 wks
Gore et al. 2006 J Appl Physiol
Rodríguez et al. 2007 J App Physiol
Truijens et al. 2008 J Appl Physiol

8. Aims
• To examine the effect on triathletes of 4 weeks of moderate-severe
IHE in a hypobaric chamber (SA 4,000-5,500 m) on
aerobic capacity
running performance
• Hypothesis: aerobic capacity and running performance would further
improve in the IHE group as compared to sea level control group

9. Subjects
• 14 male triathletes
• Age 19-37 y, height 172-185 cm, body mass 66-84 kg
• Regular training 7-25 h/wk
• Competing at regional/national level
• Continued to train at sea level throughout the study

10. Experimental Design
• Randomised controlled trial
• Subjects assigned to HYPO or NORM group (n=7 each)
• Very similar training schedule at SL (ave. 20 h/wk)
• Same supplementation (Fe, folate, vitamins A, C, & E, Mg)
HYPO
Sea level training
IHE at rest: 4 weeks, 5 d/wk, 3 h/d at 4,000-5,500 m
NORM
SL training only

11. Chronogram
6000
Simulated altitude (m)
5000 Treadmill test
4000
Field test (UMTT)
3000
Blood tests
2000
1000
0
1 8 15 22 29 36 43 50
Time (days)
t1 t2 t3
t1´ t2´
Pre Post 1 Post 2

12. Running Field Testing
• Université de Montréal Track Test (UMTT)*
to determine MAS (vVO2max) in a synthetic
400-m track
v0 = 7 km·h-1
v = 1 km·h-1 / 2 min
* Léger & Boucher 1980 Can J Appl Sports Sci

13. Treadmill Running Test
• Maximal, incremental test on a running treadmill
v0 = 6 km·h-1
v = 1 km·h-1 / 1 min
slope 5%
• Expired gas continuously measured BxB
CPXII, Medical Graphics, USA
• Highest 15 s averaged VO2 = VO2max
• Ventilatory thresholds
VT1
VT2 = RCP

14. Statistical Analysis
• MANOVA (general linear model, SPSS)
• Main effects
time: Pre, Post, Post 1 wk, Post 2 wk
treatment: HYPO vs NORM
• Time x treatment interaction
• Post-hoc paired comparisons (Student)

15. VO2max
NORM HYPO
NORM HYPO
% Change of VO2max % Change of VO2max
18
14 +3.7%
10 p=0.2
6
2
-2
-6
-10
-14
Pre Post 1 Pre Post 1

16. VT1
NORM HYPO
NORM HYPO
12 % Change in VT1 (% VO2max)
Group (NORM, HYPO) x Period Change in VT1 (% VO2max)
%
(pre, post1) = 0.017
8
4
0
-4
+3.5%
-8 p<0,05
-12
Pre Post 1 Pre Post 1
Group (NORM, HYPO) x Period (pre, post1) = 0.017

17. VT2
NORM
NORM HYPO
HYPO
12 Group
% Change in VT2 (% VO2max)
(NORM, HYPO) x Time (pre, post1) = 0.00032 2max)
% Change in VT2 (% VO
*
8
4 +3.8%
p<0,001
0
-4
-8
**
-12
Pre Post 1 Pre Post 1

18. Running Performance
NORM HYPO
NS main effects (MANOVA)
7
5
3
1
-1
-3
-5
-7
Pre Post Post 2 Pre Post Post 2

19. Field Running Performance
• No changes in MAS
in contrast with increased performance
+2.9% in 4-min trial in world-class track cyclists (IHE
15)1
+0.9% in 200-m time-trial in swimmers (IHE 10
d)2
consistent with
no improvement in 100-400 m and 3 km time-trials
in swimmers and runners3
1 Gore et al. (1998) J Sci Med Sport
2 Rodríguez et al. (2002) IX WSBMS
3 Rodríguez et al. 2007 J Appl Physiol

20. Discussion: VO2max
• NS change in VO2max (+3.7%, p=0.2)
lower than in
Runners (+5%) Hi-Lo at 2,500 m for 4 wk1
Trained climbers (+6.2%), IHE for 17 days2
Swimmers (+5.4%), IHE for 10 days3
similar to
Swimmers (+3.3%), IHE for 4 wks4
• Limited scope for increase in highly endurance-trained athletes or
reduced sample effect?
1 Levine & Stray-Gundersen (1997) J Appl Physiol 4 Rodríguez et al. (2004) Med Sci Sports Exerc
2 Casas et al. (2000) Aviat Space Environ Med 5 Gore et al. (1998) J Sci Med Sport
3 Rodríguez et al. (2002) IX WSBMS

21. VT and VCO2max
• Significant increase
AT1 +3.5%
VT2 +3.8%
consistent with LT improvement in climbers1,2 and swimmers3
• Significant decrease VCO2max -8.7%
• Changes suggesting improvement of aerobic endurance and lower
reliance on glycolitic metabolism: mechanism?
1 Rodríguez et al. 1999 Med Sci Sports Exerc
2 Casas et al. 2000 Aviat Space Environ Med
3 Rodríguez et al. 2007 J Appl Physiol

22. Intermittent Hypoxia Study 2003
HYPO Swimmers NORM Swimmers
30
HYPO NORM
+12.1% [7.0 to 17.2]
+8.9% [5.4 to 12.5] p < 0.001
20 p = 0.007
% Change in VO2 at VT
+0.4% [-2.1 to 2.9]
10 p = 0.98
0
-10
-3.5% [-0.7 to -6.2]
p = 0.56
PRE-MEAN POST1 POST2 PRE-MEAN POST1 POST2
Rodríguez et al. 2007 J Appl Physiol Group x Test F(1,10) = 6.80, p = 0.006

23. Erythropoietic Response
• EPO secretion stimulated (mean=100-440%)
• No subsequent erythropoietic response1
• Changes not attributable to an increase in total Hbmas
as in a double-blind study with runners and swimmers2
1 Abellán et al. 2004 Haematologica
2 Gore et al. 2007 J Appl Physiol

24. Conclusions
• IHE combined with SL training to moderate-severe
hypoxia did not improve track running performance
(MAS) in triathletes
• Unlike in swimmers1, change in VO2max were NS,
• This may be explained by
limited scope for further increase in ET triathletes
limited sample effect
1 Rodríguez et al. 1999 Med Sci Sports Exerc

25. Conclusions
• IHE significantly increased VT and decreased VCO2max
suggesting improved aerobic endurance capacity
not due to increased erythropoiesis or efficiency
other adaptations (ventilatory, mitochondrial)?
• Although benefits can be expected, more research is
needed to clarify the effect of IHE in endurance athletes

26. IMAS
Institut Municipal
d’Investigació Mèdica. IMIM
Pharmacology Research Unit