Solbiati Sarah, Caiani Enrico Gianluca
Politecnico di Milano, Department of Electronics, Information and Bioengineering, Milan, Italy.
IRCCS Istituto Auxologico Italiano, Milan, Italy.
NPJ Microgravity. 2025 Jul 31;11(1):48. doi: 10.1038/s41526-025-00509-5.
Microgravity challenges cardiovascular regulation, necessitating adaptive responses to maintain homeostasis. This retrospective study examines the changes in heart rate variability (HRV) induced by head-down tilt (HDT) bed rest, a ground-based analog for microgravity. Standardized 24-h Holter electrocardiograms (ECG) were collected from 66 male volunteers across six ESA HDT campaigns of different durations (5, 21, and 60 days). HRV indices, including time, frequency, and nonlinear metrics, were computed to evaluate autonomic modulation during HDT and following re-exposure to orthostatic stress. Results showed decreased high- and low-frequency power during HDT, indicating impaired autonomic modulation. Additional alterations were observed at HDT discontinuation, likely reflecting cardiovascular deconditioning and gravity readaptation. The use of harmonized protocols and a large pooled dataset provided valuable insights into cardiovascular adaptation to HDT. These findings emphasize the importance of standardized protocols and large pooled datasets in future studies investigating cardiovascular responses to simulated microgravity.
微重力对心血管调节构成挑战，需要适应性反应来维持体内平衡。这项回顾性研究考察了头低位倾斜（HDT）卧床休息（一种地面模拟微重力的方式）所引起的心率变异性（HRV）变化。在欧洲航天局（ESA）开展的6次不同时长（5天、21天和60天）的HDT活动中，从66名男性志愿者身上收集了标准化的24小时动态心电图（ECG）。计算了HRV指标，包括时域、频域和非线性指标，以评估HDT期间以及再次暴露于直立位应激后的自主神经调节情况。结果显示，HDT期间高频和低频功率降低，表明自主神经调节受损。在HDT结束时还观察到了其他变化，这可能反映了心血管失健和重力再适应情况。使用统一的方案和一个大型汇总数据集为心血管对HDT的适应提供了有价值的见解。这些发现强调了标准化方案和大型汇总数据集在未来研究心血管对模拟微重力反应中的重要性。
