Is decision making in hypoxia affected by pre-acclimatisation? A randomized controlled trial.

INTRODUCTION Decision making is impaired in hypoxic environments, which may have serious or even lethal consequences for mountaineers. An acclimatisation period prior to high altitude exposures may help to overcome adverse effects of hypoxia. Thus, we investigated possible effects of short-term pre-acclimatisation on decision making in hypoxia. METHODS In a randomized controlled study design, 52 healthy participants were allocated to a hypoxia group (HG: short-term pre-acclimatisation by the use of intermittent hypoxia 7×1h at FiO2=12.6%, equivalent to 4500m) or a control group (CG: sham pre-acclimatisation 7×1h at FiO2=20.9%, equivalent to 600m). The number of risky decisions was assessed using the Game of Dice Task at four time points during a 12-hours stay in hypoxia (FiO2=12.6%). RESULTS 42 (HG: 27, CG: 25) participants completed the study. The number of risky decisions was significantly (p=0.048 as determined by 4×2 ANCOVA) reduced in the hypoxia group compared to the control group, partial η2=0.11, when the age-effect on decision making was controlled. Self-reported positive affective valence prior to decision making was negatively related to the number of risky decisions, r<-0.38. CONCLUSION Short-term pre-acclimatisation might influence decision making in hypoxia in a positive way and might be considered as a risk-reducing preparation method prior to exposures to hypoxic environments. Positive affective states seem to have a medium-sized protective effect against risky decision making.