Heart rate variability and acute mountain sickness during the acclimatization period of altitude training camp in elite swimmers - Calderon-Soto, C.; Morales, A. J.; Rodriguez, F. A.; Iglesias, X.; Feriche, B.; Vazguez, J.; Rodriguez-Zamora, L.; Barrero, Z.; Hynynen, E. (Sport Science Research Group, INEFC-Barcelona, 2012)