INTRODUCTION: Altitude chambers are used for training aircrews in a hypobaric hypoxic environment to better prepare them for pressurization and oxygen malfunction incidents during flights. However, adverse effects may occur during training sessions, with decompression sickness (DCS) being a major concern. The aim of this study was to examine the risks of different adverse effects during altitude chamber trainings (ACT) in the Israeli Air Force (IAF) facility and to compare them to other training facilities.METHODS: We retrospectively reviewed the records of 1627 individuals in the IAF who were trained in the altitude chamber between 2015 and 2019. Data regarding adverse effects and training safety were extracted. Literature review of altitude chamber trainings was performed and adverse effects rates were compared.RESULTS: There were a total of 91 adverse effects cases in the IAF during the study period. The overall risk rate for an adverse effect was 5.59%. The most common adverse effect was middle ear and sinus barotrauma (69.3% of adverse effects cases), followed by breathing problems (14.3%) and DCS cases (9.9%).CONCLUSIONS: Mitigating the risk for DCS should be major concern during ACT. We recommend setting a standard protocol for an ACT which includes a 45-min preoxygenation period, a maximal ascent rate of 3000 ft · min⁻¹ (914 m · min⁻¹), and setting a maximum altitude of 25,000 ft (7620 m) for fixed-wing trainees.Nakdimon I, Ben-Ari O. Mitigating risks of altitude chamber training. Aerosp Med Hum Perform. 2022; 93(11):811–815.