PMID- 33086469
OWN - NLM
STAT- MEDLINE
DCOM- 20210111
LR  - 20210111
IS  - 1660-4601 (Electronic)
IS  - 1661-7827 (Print)
IS  - 1660-4601 (Linking)
VI  - 17
IP  - 20
DP  - 2020 Oct 19
TI  - Vagal Threshold Determination during Incremental Stepwise Exercise in Normoxia 
      and Normobaric Hypoxia.
LID - 10.3390/ijerph17207579 [doi]
LID - 7579
AB  - This study focuses on the determination of the vagal threshold (T(va)) during 
      exercise with increasing intensity in normoxia and normobaric hypoxia. The 
      experimental protocol was performed by 28 healthy men aged 20 to 30 years. It 
      included three stages of exercise on a bicycle ergometer with a fraction of 
      inspired oxygen (FiO(2)) 20.9% (normoxia), 17.3% (simulated altitude ~1500 m), 
      and 15.3% (~2500 m) at intensity associated with 20% to 70% of the maximal heart 
      rate reserve (MHRR) set in normoxia. T(va) level in normoxia was determined at 
      exercise intensity corresponding with (M +/- SD) 45.0 +/- 5.6% of MHRR. Power output 
      at T(va) (PO(th)), representing threshold exercise intensity, decreased with 
      increasing degree of hypoxia (normoxia: 114 +/- 29 W; FiO(2) = 17.3%: 110 +/- 27 W; 
      FiO(2) = 15.3%: 96 +/- 32 W). Significant changes in PO(th) were observed with 
      FiO(2) = 15.3% compared to normoxia (p = 0.007) and FiO(2) = 17.3% (p = 0.001). 
      Consequentially, normoxic %MHRR adjusted for hypoxia with FiO(2) = 15.3% was 
      reduced to 39.9 +/- 5.5%. Considering the convenient altitude for exercise in 
      hypoxia, PO(th) did not differ excessively between normoxic conditions and the 
      simulated altitude of ~1500 m, while more substantial decline of PO(th) occurred 
      at the simulated altitude of ~2500 m compared to the other two conditions.
FAU - Neuls, Filip
AU  - Neuls F
AD  - Department of Natural Sciences in Kinanthropology, Faculty of Physical Culture, 
      Palacky University Olomouc, 771 11 Olomouc, Czech Republic.
FAU - Krejci, Jakub
AU  - Krejci J
AUID- ORCID: 0000-0002-7236-8328
AD  - Department of Natural Sciences in Kinanthropology, Faculty of Physical Culture, 
      Palacky University Olomouc, 771 11 Olomouc, Czech Republic.
FAU - Jakubec, Ales
AU  - Jakubec A
AD  - Department of Natural Sciences in Kinanthropology, Faculty of Physical Culture, 
      Palacky University Olomouc, 771 11 Olomouc, Czech Republic.
FAU - Botek, Michal
AU  - Botek M
AD  - Department of Natural Sciences in Kinanthropology, Faculty of Physical Culture, 
      Palacky University Olomouc, 771 11 Olomouc, Czech Republic.
FAU - Valenta, Michal
AU  - Valenta M
AD  - Department of Natural Sciences in Kinanthropology, Faculty of Physical Culture, 
      Palacky University Olomouc, 771 11 Olomouc, Czech Republic.
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20201019
PL  - Switzerland
TA  - Int J Environ Res Public Health
JT  - International journal of environmental research and public health
JID - 101238455
SB  - IM
MH  - Adult
MH  - Altitude
MH  - *Exercise/physiology
MH  - Exercise Test
MH  - Humans
MH  - Hypoxia
MH  - Male
MH  - *Oxygen Consumption
MH  - Young Adult
PMC - PMC7590016
OTO - NOTNLM
OT  - autonomic nervous system
OT  - exercise intensity
OT  - saturation
OT  - simulated altitude
OT  - vagal withdrawal
COIS- The authors have no conflict of interest. The funders had no role in the design 
      of the study; in the collection, analyses, or interpretation of data; in the 
      writing of the manuscript, or in the decision to publish the results.
EDAT- 2020/10/23 06:00
MHDA- 2021/01/12 06:00
PMCR- 2020/10/01
CRDT- 2020/10/22 01:01
PHST- 2020/07/24 00:00 [received]
PHST- 2020/10/01 00:00 [revised]
PHST- 2020/10/14 00:00 [accepted]
PHST- 2020/10/22 01:01 [entrez]
PHST- 2020/10/23 06:00 [pubmed]
PHST- 2021/01/12 06:00 [medline]
PHST- 2020/10/01 00:00 [pmc-release]
AID - ijerph17207579 [pii]
AID - ijerph-17-07579 [pii]
AID - 10.3390/ijerph17207579 [doi]
PST - epublish
SO  - Int J Environ Res Public Health. 2020 Oct 19;17(20):7579. doi: 
      10.3390/ijerph17207579.