%0 Journal Article %A Giovanni Papi Renzetti %A Guido Giardini %A Gaia Mandolesi %A Bruna Catuzzo %A Annalisa Cogo %T Maintaining a good ventilatory efficiency in the transition between normoxia (N) and hypoxia (H) at rest predicts a better oxygenation (SaO2) during exercise in hypoxia %D 2014 %J European Respiratory Journal %P P2108 %V 44 %N Suppl 58 %X Ventilatory efficiency in hypoxic conditions can be defined as the amount of ventilation (VE) required to achieve a given level of SaO2. Index of ventilatory efficiency (IE) is the ratio SaO2/VE corrected by height. A good IE has been proved advantageous during exposure to high altitude (1). Moreover, a ventilatory pattern characterized by low respiratory rate (RR) and high tidal volume (VT) for the same amount of VE is associated to better SaO2 (2). We tested the ventilatory adaptation in relation to SaO2 in 36 mountain guides (M, age 29-57) at rest in N and at rest and during exercise in H simulating 4500m (Altitrainer, Simtec, CH; Quark, COSMED, I) ). For each frame we calculated the mean value of VE, VT, RR and the IE. Data during exercise refer to the same work intensity. As expected, VE increased and SaO2 decreased in H vs. N, changing further during exercise. According to the difference in IE between N and H at rest (ΔSaO2/VE) we divided the subjects into 4 groups: High Efficiency (IE = + 1.36), Moderate (-1.16), Mild (-3) and Low (-5.4). In group High, the SaO2 during exercise is higher than in group Low (76.8 vs. 64.66 p = 0.027) with a significantly greater increase in VT as compared to RR for the same increase in VE. A significant correlation is found between the ΔSpO2/VE at rest and the oxygen desaturation during exercise in H (r=0.46 p=0.005). We conclude that subjects with a better IE at rest in H, spontaneously adopting slower and deeper ventilation have the capability to maintain a better oxygenation during exercise in H.1) Bernardi L, Eur J Appl Physiol 2007 2) Bernardi L J Hypertens, 2001. %U