1. Effects of Altitude Training on Heart Rate Variability in Orthostatic Test in Elite Swimmers
F.A. Rodríguez, FACSM1, X. Iglesias 1, B. Feriche 2, C. Calderón 3, X. Ábalos 1, J. Vázquez1, A. Barrero 1, L. Rodríguez 1, E. Hynynen4, B.D. Levine, FACSM5
1 INEFC, University of Barcelona, Spain, 2 FCAFyD, University of Granada, Spain, 3 Sierra Nevada High Altitude Training Center, Granada, Spain, 4 KIHU – Research Institute for Olympic Sports, Jyväskylä, Finland, 5 IEEM / UT Southwestern, Dallas, TX, USA
Abstract Results Discussion
Different stressors, like athletic training, can change the autonomic modulation of the heart. This can be evaluated with heart rate
variability (HRV) analysis. Acute hypoxia is also known to attenuate parasympathetic activity and accentuate the sympathetic activity.
The training load was not different in both groups during the 3-week intervention but This study showed that: 1) supine HRV decreased during AT whereas it
Whether these changes in autonomic modulation will disappear with altitude acclimatization remains unclear. PURPOSE: This study was was lower during the week after in Hi-group when compared to Lo-group (P=0.003). increased during sea level training, and returned to baseline levels one week
made to investigate the effects of 3-week moderate altitude training on HRV in elite swimmers. METHODS: 9 elite swimmers (Hi) of
international level (5 women and 4 men, age 19.4 ± 1.6 years) lived and trained 3 weeks at Sierra Nevada, Spain (2,320 m). Control group An interaction of group, time and TRIMPs was found in change in spectral power of later, 2) in contrast, standing HRV gradually increased at the end of the AT
(Lo) consisted of 11 swimmers of similar level (7 women and 4 men, age 17.9 ± 1.9 years), who lived and trained at sea level. RR-intervals supine LF and HF during the intervention period showing increased HRV in Lo group period and tended to remain high level after one week, and 3) the band
were recorded every morning in supine (8-min) and orthostatic (6-min) positions with beat-by-beat heart monitors. Breathing was paced to
12 breaths/min. Recordings were done during the 3-week intervention period and one week before and after. HRV was analyzed from the and decreased HRV in Hi-group (Fig. 1). Also LF and LF/HF ratio during standing power spectra suggest that AT, in contrast to training at sea level, induced
last 5-min period of both positions with FFT spectral power analysis. TRIMPs of every training session were calculated to estimate training
load. HRV results are averaged over every week and presented as relative percentage changes. RESULTS: The training load was similar
increased more in Hi-group than in Lo-group during the intervention at low TRIMPs parasympathetic withdrawal and likely increased sympathetic activity.
in both groups during the 3-week intervention but was lower during the week after in Hi-group when compared to Lo-group (P=0.003). An only at the <TRIMPs=median=169 au (Fig. 2). Classically, acute exposure to high altitude is believed to induce a decrease
interaction of group, time and TRIMPs was found in change in spectral power of supine LF (-40% vs. +36%, P=0.02) and HF (-46% vs.
+55%, P=0.01) during the intervention period showing increased HRV in Lo group and decreased HRV in Hi-group. Also LF (+93% vs.
in HRV and an increase in LF/HF in supine position, perhaps as a defense
+12%, P=0.01) and LF/HF ratio (+79% vs. -2%, P=0.01) during standing increased more in Hi-group than in Lo-group in the end of the against hypoxic stress; after acclimatization HF increases whereas LF activity
intervention. CONCLUSION: The present findings of lower HRV in Hi-group than in Lo-group suggest that the physiological stress of 300 300
training at moderate altitude leads to parasympathetic withdrawal and possibly increased sympathetic activity even after night rest. These Lo decreases (cit. Schmitt et al. 2006). Similarly, strenuous training has been
250 250
changes in autonomic modulation seem to last longer than for the first week after altitude training camp. Hi
P=0.004
shown to induce a conversion from vagal to sympathetic predominance in
200 200
elite athletes (Iellamo et al. 2002). In contrast with previous reports (Atlaoui et
Introduction
P<0.001
P=0.001 P=0.006
150 150
al. 2007), HRV showed significant changes in the follow-up of these elite
Δ HFsu power (%)
Δ LFsu power (%)
100 100
Different stressors, like athletic training, can change the autonomic modulation of the swimmers and using the orthostatic test may reveal additional information on
50 50
heart. This can be evaluated with heart rate variability (HRV) analysis. Acute hypoxia the autonomic modulation of the heart. We could speculate that the upright
0 0
is also known to attenuate parasympathetic activity and to accentuate the sympathetic position revealed information about carotid chemosensitivity, perhaps
-50 -50
activity. Whether these changes in autonomic modulation will disappear or be increasing baroreceptor–chemoreceptor interaction.
-100 -100
accentuated with altitude acclimatization remains unclear. This study was made to
Conclusions
-150 -150
investigate the effects of 3-week altitude training (AT) on HRV in elite swimmers. Pre Wk 1 Wk 2 Wk 3 Post Pre Wk 1 Wk 2 Wk 3 Post
Figure 1. Changes in supine LF and HF power (% Pre) § Elite swimmers living and training for 3 weeks at 2,320 m experienced
Methods a decline in supine HRV and a gradual increase in standing HRV. Sea
300 300 level training at similar load induced a mirror like pattern during the
Elite swimmers P=0.04
Altitude
Lo group
250 250 P=0.04 supine position and no change during standing
(m) Hi group
200 200
n= 9 (5 F, 4 M) 19.4 ± 1.6 y n= 11 (7 F, 4 M) 17.9 ± 1.9 y
2,320
150
§ HRV was lower during altitude training as compared to sea level,
Pre Hi Post 150
Δ LF/Hfor ratio (%)
Δ LFor power (%) suggesting that the physiological stress of training at moderate
100 100
Training altitude leads to parasympathetic withdrawal and possibly increased
50 50
Altitude 2,320 m Sea level sympathetic activity even after night rest; these changes seem to last
0 0
longer than the first week after the altitude training camp
-50 -50
Orthostatic test
References
Lo -100 -100
0
8 min supine 6 min orthostatic -150 -150
-1 0 1 2 3 +1 Weeks
Pre Wk 1 Wk 2 Wk 3 Post Pre Wk 1 Wk 2 Wk 3 Post
1. Atlaoui D. et al. 2007. Int J Sports Med, 28: 394-400
RR intervals analysis 2. Cornolo J. et al. (2006) Eur J Appl Physiol 96:389-96
Figure 2. Changes in orthostatic LF power and LF/HF ratio (% Pre) 3. Iellamo F. et al. (2002) Circulation 105:2719–2724
FFT spectral
5-min windows Kubios HRV 2.0
power analysis 4. Schmitt L. et al. (2006) Int J Sports Med 27:226-31
Institute for Exercise and
Environmental Medicine
Supported by CSD (35/UPB10/10, 05/UPB32/10) and MICINN (DEP2009-09181) grants