Orthostatic stress and autonomic cardiovascular modulation after spaceflight
Abstract
Introduction Changes in the cardiovascular control contribute to the occurrence of orthostatic intolerance after space flight Long-term recovery of the autonomic nervous system has rarely been studied Heart rate variability HRV and blood pressure variability BPV provide a non-invasive means to study the autonomic cardiovascular modulation Methods ECG and continuous blood pressure was measured for at least 10 minutes in supine and standing position 45 days before launch and at 1 2 4 9 15 19 and 25 days after return to Earth These measurements were performed in 5 cosmonauts during short term space missions 10 days Results Measurements in supine position and sitting position did not show as high differences as the measurements in standing position During standing after spaceflight HF was extremely depressed compared to the preflight conditions p 0 005 The recovery of the HF power was not completed at day 25 LF power of BPV was slightly increased up to 25 days after landing Heart rate in standing position at landing day was significantly higher compared to preflight and remained higher up to 25 days after landing The baroreflex mechanism was also extremely depressed immediately after landing and showed a gradual recovery p 0 05 compared to preflight values Conclusion After return to Earth especially the vagal autonomic modulation is extremely depressed This also affects the baroreflex feedback The recovery of the autonomic nervous system takes several weeks and is not completed 25 days after return to Earth The
- Publication:
-
36th COSPAR Scientific Assembly
- Pub Date:
- 2006
- Bibcode:
- 2006cosp...36..959B