RESUMO
Antarctic climate is challenging, since the cold, wind and sensory monotony are stressful stimuli to individuals. Moreover, camp activities and heavy clothes may contribute to increase physiological strain. Thus, we aimed to characterise the physiological demand of a 24-day period in the Antarctic field and then to evaluate the effect of this expedition on the aerobic fitness in individuals with heterogeneous initial aerobic fitness (as determined by estimating maximum oxygen consumption - VÌO2MAX). Before and after the 24-day period in Antarctica, 7 researchers and 2 mountaineers were subjected to incremental tests to estimate their VÌO2MAX. Field effort was characterised by measuring heart rate (HR). During the field trips, their HR remained 33.4% of the recording time between 50-60% HRMAX, 22.3% between 60-70% HRMAX, and only 1.4% between 80 and 90% HRMAX. The changes in estimated VÌO2MAX during the expedition depended on the pre-expedition aerobic fitness. The post-expedition VÌO2MAX increased by 5.9% and decreased by 14.3%in individuals with lower (researchers) and higher (mountaineers) initial VÌO2MAX, respectively. We concluded that physical effort in the Antarctic field is characterised as predominantly of low- to moderate-intensity. This effort represented an effective training load for individuals with lower initial VÌO2MAX, but not for those with higher VÌO2MAX.