Autonomic function testing on board the ISS – update on "Pneumocard".
- Paper number
IAC-05-A1.1.06
- Author
Dr. Jens Tank, Franz Volhard Clinical Research Center, Charité, Berlin-Buch, Germany
- Coauthor
Dr. Irina I. Funtova, Institute for Biomedical Problems, Russia
- Coauthor
Prof. André Diedrich, Vanderbilt University, GCRC, United States
- Coauthor
Dr. Juergen Drescher, German Aerospace Center (DLR), United States
- Coauthor
Dr. Victor M. Baranov, Institute for Biomedical Problems, Russia
- Year
2005
- Abstract
it bf Aim Investigations of heart rate variability (HRV) during long term space flights on board the ”MIR” have shown characteristic changes of autonomic cardiovascular control. Therefore, alterations of the autonomic nervous system occurring during spaceflight may be responsible for inflight and postflight disturbances. The devices ”Puls” and ”Pneumocard” were developed to further investigate autonomic cardiovascular and respiratory function on board the ISS. it bf Method The hard-software diagnostic complex "Puls" was used during inflight experiments on-board ISS for autonomic function monitoring. ECG, photoplethysmography and breathing were assessed in three male cosmonauts during ISS missions 6, 7, and 8 (flight lengths 139, 143, and 189 days). Recordings were made 60, and 30 days prior to the flight, every four weeks during flight, and 3 and 6 days postflight. during spontaneous breathing, metronomic breathing at rates of 12 and 6 per min, inspiratory, and expiratory apnea. Orthostatic testing was performed pre- and postflight. it bf Results Heart rate (HR) decreased in two cosmonauts (preflight: 79 and 69 bpm, inflight: 48 and 59 bpm) and increased in one cosmonaut (preflight 49 bpm, inflight 61 bpm). Breathing frequency decreased in two cosmonauts and increased in one cosmonaut. Blood pressure (BP) remained low or normal in all cosmonauts during flight. Postflight HR and BP values increased compared to inflight data but were similar compared to preflight data in two cosmonauts. An increase of postflight BP values was obtained in one cosmonaut. Heart rate variability (HRV) analysis was reliable only during metronomic breathing due to the low breathing rate of about 6/min in 2 cosmonauts and showed high interindividual differences. HRV during 5 sec breathing remained high during flight in all three cosmonauts. High frequency power even increased early during flight and declined towards the end of the flight. The LF/HF ratio or so called sympatho-vagal balance was highest after flight. The low frequency power during 10 sec breathing decreased continuously during flight. The pulse wave traveling time did not change significantly during flight, indicating no dramatic changes in vessel compliance. it bf Conclusion Our data suggest an initial increase of parasympathetic HR control early during flight and support the hypothesis that autonomic HR control is stable during flight. The decrease in LF-power during deep breathing may indicate a loss of parasympathetic reserve. The parameter changes occurring postflight were much more pronounced than during flight in the three investigated cosmonauts. Our results demonstrate that autonomic function testing on-board the ISS is feasible and measurements during episodes of space sickness may add useful information.
- Abstract document
- Manuscript document
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