Author(s): JIMÉNEZ, J.A., FERICHE, B., PÉREZ-REGALADO, S., BENAVENTE, C., PADIAL, P., GARCÍA RODRÍGUEZ, S., TIMÓN, R., Institution: UNIVERSITY OF EXTREMADURA , Country: SPAIN, Abstract-ID: 806

INTRODUCTION:
Acute exercise under hypoxic conditions induces a drop in blood oxygen levels (hypoxemia) and impact in continuous oxygen supply to tissues (1). Terrestrial altitude presents a logistical challenge. For this reason, certain research endeavours to replicate high-altitude scenarios within normobaric hypoxia (NH) (2). However, one of the main concerns in using NH systems is the accumulation of CO2 levels and increased temperature and humidity inside the tent resulting from athletes’ exhalation (3). Therefore, combining reduced oxygen availability and increased environmental stressors could affect performance (4). The present study aims to analyse the effects of a resistance training (RT) period under two different NH environment emplacements on strength development.
METHODS:
Nineteen men (22,16 ± 2,94 years; 176,79 ± 7,47 cm; 76,32 ± 11,00 kg) participated in an 8-week- hypertrophy RT program (3 sessions /week) under systemic moderate NH (FiO2 = 15,9%) in a tent (8 m2; 50 l/min/persona) or in a room (60 m2; 900 l/min/persona). Before and after the program, one repetition maximum (1RM) in back squat and bench press exercises were evaluated. Maximal blood lactate and rating of perceived exertion (RPE min25) were also measured after the programs first and last sessions. Environmental CO2 was monitored during the RT sessions.
RESULTS:
The values of change in CO2 concentration from the beginning to the end of the session were significantly higher in the tent (4947,70 ± 1918,84 ppm) compared with the room (550,31 ± 405,40 ppm). 1RM increased in both groups (p < 0.05), with no differences between groups (p > 0.05). No differences were found in the RPE and lactate between conditions (p > 0.05).
CONCLUSION:
Results reveal a strength development after a RT period in NH regardless of the environmental additional stressors. However, such a higher CO2 concentration measured in the NH tent could lead to a greater physiological strain during exercise, impacting the normal functioning of organic systems not evaluated in this study. Therefore, the type of equipment used must be considered when conducting NH training.

References:
1. Billaut F., et al. PLoS ONE. 2013;8: e77297.
2. Coppel J., et al. Extrem Physiol Med. 2015;4(1).
3. Vasquez-Bonilla AA., et al. J Clin Med. 2021; 22;10(21):4879.
4. Girard O., et al Front. Sports Act. Living. 2020; 2:26.

Funding: This research was funded by the Spanish Ministry of Science, Innovation and Universities under grant number PGC2018-097388-B-I00 and by the Andalusian FEDER Operational Program under grants number A-SEJ-246-UGR18 & B-CTS-374-UGR20.