Abstract Objective There is limited work on the physiological demands of lifting activities at different altitudes and different lifting frequencies when wearing different types of shoes. This study aimed to examine the heart rate variability (HRV) and ventilation responses of individuals in normobaric hypoxia (ambient oxygen of 15%, 18%, and 21%) while doing lifting tasks and wearing three types of different safety shoes (“light, medium, and heavy-duty”) at two different lifting frequencies (“1 lift/min and 4 lifts/min”). Methods Using an experimental study design, two sessions were conducted by ten male university students that included an acclimatization and training session followed by experimental lifting. The study used a four-way repeated measures design (4 independent and twenty-one responses, i.e., twelve HRV and nine ventilation responses). Results The findings highlighted substantial low HRV and ventilation parameters for the light workload stress in the form of higher ambient oxygen content and lowered lifting frequency while wearing light safety shoe type. It also presented an increase in the physical demand, followed by increased lifting frequency and replication with increased mean heart rate and decreased mean RR, very low frequency (VLF) power, low frequency (LF) power, and low frequency to a high-frequency ratio (LF/HF). Conclusion Our findings suggest that if a safe lifting load limit is applied for workers in the industrial environment, the risk of musculoskeletal disorders will be mainly decreased, and the rate of production will be better with ambient oxygen content and appropriate safety shoes. This research would safeguard industrial workers' physical capacities and future health risks.

中文翻译：

---

缺氧、安全鞋类型和提升频率对心血管和通气反应的影响

摘要 目的在不同海拔、不同提举频率下，穿不同鞋型时提举活动的生理需求研究有限。本研究旨在检查在常压缺氧（环境氧气为 15%、18% 和 21%）下个体在执行举重任务和穿着三种不同安全鞋（“轻、中型和重型”）两种不同的提升频率（“1 次提升/分钟和 4 次提升/分钟”）。方法 使用实验研究设计，由 10 名男大学生进行了两次训练，其中包括适应训练和训练，然后是实验举重。该研究使用了四向重复测量设计（4 个独立和 21 个响应，即，十二个 HRV 和九个通气响应）。结果 研究结果强调，在穿着轻型安全鞋时，以较高的环境氧含量和较低的举重频率的形式，轻工作负荷压力下的 HRV 和通风参数明显偏低。它还呈现出身体需求的增加，随后是提升频率和复制增加，平均心率增加，平均 RR 降低，极低频 (VLF) 功率，低频 (LF) 功率，以及低频到高频比率 (LF/HF)。结论 我们的研究结果表明，如果对工业环境中的工人应用安全起重载荷限制，肌肉骨骼疾病的风险将主要降低，并且在环境含氧量和合适的安全鞋的情况下，生产率会更好。