The Hypoxico Everest Summit II Altitude Generator produces normobaric hypoxic conditions, which are commonly used in altitude acclimation. Despite being used routinely within applied sport science, this system is yet to be independently validated. Thus, the aim of this study was to explore within- and between-day inter- and intra-machine reliability and validity. Two Hypoxico Everest Summit II Altitude Generators were investigated for six altitude settings in a randomised order (0.5, 3.0, 5.5, 8.0, 10.5, 12.0). Following institutional ethics approval, Hypoxico generated air was sequentially pumped into three Douglas bags, each with a 1-min collection period. Samples were collected on eight occasions, measuring inter- and intra-machine reliability, both within-day (9 AM–2 PM) and between-day (48-h) with samples analysed to determine FiO₂ (%) and volume (L·min⁻¹). Coefficient of variation (CV) was calculated for FiO₂ and volume for each altitude setting. Mean CV for FiO₂ did not exceed 0.42% within-day, 0.49% between-day and 0.81% inter-machine. Volume mean CV did not exceed 0.85% within-day, 0.91% between-day and 1.17% inter-machine. One-sampled t-tests were conducted comparing Hypoxico reference values with collected samples using equivalent FiO₂ for each altitude setting with a Bonferroni corrected significance set at p < 0.004. Settings 3.0, 5.5, 8.0, 10.5 and 12.0 all produced significantly different (p < 0.001) FiO₂ concentrations than the reference values stated (−0.51, −0.97, −0.72, +0.41 and +0.40%, respectively). Altitude setting and 1-min volume had an inverse relationship. All settings produced a significantly lower (p < 0.001) volume by 21.80 to 35.40 L·min⁻¹ as compared to the company’s claim of 126.6 L·min⁻¹. The Hypoxico Everest Summit II produced a reliable and consistent air feed; however, the manufacturer’s reference values demonstrated poor agreement with machine produced FiO₂ and volume. Therefore, it is recommended that athletes, practitioners and researchers self-validate the altitude generator post-warm-up using an accurate oxygen sensor for accuracy and safety purposes.

Hypoxico Everest Summit II海拔发生器会产生常压低氧条件，通常在海拔适应中使用。尽管在应用运动科学中经常使用该系统，但该系统尚未得到独立验证。因此，本研究的目的是探讨一天之内和一天之内机器间和机器内的可靠性和有效性。研究了两个Hypoxico Everest Summit II高度生成器，以随机顺序（0.5、3.0、5.5、8.0、10.5、12.0）对六个高度设置进行了研究。经机构伦理批准后，Hypoxico产生的空气被依次泵入三个道格拉斯袋中，每个袋的收集时间为1分钟。在一天之内（上午9点至下午2点）和一天之间（四十八小时）内，共采集了八次样品，测量了机器间和机器内的可靠性，并分析了样品以确定FiO₂（％）和体积（L·min ^-1）。针对每个海拔设置计算FiO ₂和体积的变异系数（CV）。FiO _2的平均CV在一天之内不超过0.42％，一天之内不超过0.49％，机器间不超过0.81％。日内成交量平均CV不超过0.85％，日间不超过0.91％，机器间不超过1.17％。进行了一次抽样的t检验，将低氧参考值与收集的样品进行比较，对于每个海拔设置，使用等效的FiO ₂，将Bonferroni校正后的显着性设置为p  <0.004。设置3.0、5.5、8.0、10.5和12.0产生的 FiO ₂显着不同（p <0.001）浓度高于参考值（分别为-0.51，-0.97，-0.72，+ 0.41和+ 0.40％）。高度设置和1分钟的音量成反比关系。所有的设置产生了显著降低（p 由21.80 <0.001）体积35.40 L·分钟^-1相比于公司的的126.6大号权利要求·分钟^-1。Hypoxico Everest Summit II产生了稳定可靠的空气供给；但是，制造商的参考值显示出与机器生产的FiO ₂和体积的一致性差。因此，建议运动员，从业人员和研究人员使用精确的氧气传感器在预热后对海拔发生器进行自我验证，以确保准确性和安全性。