Cardiovascular and Cerebrovascular Control on Return from ISS (CCISS) will study the effects of long-duration space flight on crewmembers' heart functions and their blood vessels that supply the brain. Learning more about the cardiovascular and cerebrovascular systems could lead to specific countermeasures that might better protect future space travelers. This experiment is collaborative effort with the Canadian Space Agency.Principal Investigator(s)
Johnson Space Center, Human Research Program, Houston, TX, United States
National Aeronautics and Space Administration (NASA)Sponsoring Organization
Human Exploration and Operations Mission Directorate (HEOMD)Research Benefits
Information PendingISS Expedition Duration:
April 2007 - March 2010Expeditions Assigned
15,16,18,19/20,21/22Previous ISS Missions
CCISS is a continuing investigation which began observation of the first subject during ISS Expedition 15.
The ability to maintain arterial blood pressure and brain blood flow immediately on return to Earth after prolonged space flight is one of the most critical factors for crew health and safety. Although the heart rate component of the arterial baroreflex is impaired on return from space, this is not in itself a critical issue as crewmembers who are about to faint normally have markedly elevated heart rate. Rather, their inability to maintain blood pressure appears to be related to inadequate increases in peripheral vascular resistance. This study will incorporate a new methodology that determines the simultaneous gains of the arterial and cardiopulmonary baroreflexes in the control of peripheral vascular resistance.
A series of six objectives have been identified that will allow a more complete understanding of any alteration in cardiovascular or cerebrovascular responses following long duration space flight. The first two will be addressed with very brief inflight experiments that monitor the heart rate component of the arterial baroreflex and the relationship between heart rate variability and physical activity as indicators of autonomic nervous system control. The remaining objectives will be evaluated during a 32-minute test protocol conducted pre- and immediately postflight. During this test period, the central vein compliance will be monitored. In addition, the arterial and cardiopulmonary baroreflexes will be monitored during experiments that use an optimized schedule of lower body negative pressure (LBNP) to manipulate arterial and central venous blood pressures. Within these same experimental sessions assessments of cerebrovascular responsiveness to changes in arterial blood pressure and arterial partial pressure of carbon dioxide (CO2). It is anticipated that the ability to regulate blood pressure through baroreflex control of blood vessel constriction will be impaired after space flight. Similarly, it is expected that brain blood flow will be more sensitive to changes in arterial blood CO2 and, thus, will not be as tightly regulated after space flight.
The information derived from this study will help to better understand the effects of spaceflight on cardiovascular and cerebrovascular functions. By gaining increased knowledge of the specific components of the cardiovascular and cerebrovascular systems that deviate from the normal Earth-baseline responses, it will be possible to recommend specific countermeasures that might better protect future space travelers from complications that could put them at risk on return to the effects of gravity as will occur on re-entry to Earth or landing on the moon or Mars.Earth Applications
The risk of fainting and falling is increased in older adults. Falls are very serious because they often cause fracture of the hip which is a major cause of prolonged disability, loss of independence and unfortunately for a high percentage of individuals the complications from the fracture will lead to death. Gaining improved knowledge of the mechanisms of loss of blood pressure and the warning signs that might predict risk will reduce the incidence of fainting and falls in the elderly.
A total of 6 long-duration crewmembers are needed as subjects for the experiment. Baseline data for each subject will be collected at L-30 (Launch minus 30 days) for the Baro Study, 24-hr Heart Rate Study, and LBNP protocol. Baseline data will also be collected at R+1 (Return plus 1 day) for the Baro and 24-hr Heart Rate Studies and R+0 (U.S.) or R+1 (Russia) for the LBNP protocol.Operational Protocols
Crewmembers will perform CCISS operations on FD+14 (+7) (Flight Day 14) and R-14 (-7). During Day 1 operations the crewmember will don and activate the Actiwatches, CBPD, and Holter Monitor and conduct a 10-minute Baro Study. During the Baro Study, the crewmember will breathe normally for 5 minutes and then breathe at a set pace for 5 minutes. The crewmember will doff the CBPD after the conclusion of the Baro Study. The Actiwatch and Holter Monitor are worn to collect data during the 24-hr Heart Rate Study. Day 2 operations consist of the crewmember downloading data from the 24-hr Heart Rate Study and doffing the hardware.
Early evidence from long-duration flights indicates general cardiovascular fitness reduction, along with chronic elevations in arterial blood pressure in the brain and elevated inspired carbon dioxide (CO2) compared with normal upright posture on Earth. Recent studies investigated the spontaneous blood pressure feedback and markers of cardiovascular control, changes in heart rate (HR), as well as dynamic autoregulation of brain blood flow and CO2 responsiveness in astronauts living for 2?6 months on the ISS.
Overall, there was no change in indicators of cardiovascular stability during long-duration space flight and only relatively small changes postflight at rest in the seated position. Inflight measurements of heart rate, blood pressure, and blood pressure regulation versus preflight revealed no significant changes. Very small increases in resting heart rate and a 25?34% reduction in the arterial blood pressure reflex response postflight reflected relatively modest levels of decreased cardiovascular muscle tone and fitness. It was also found that astronauts maintained their preflight heart rate during daily activities while living on the ISS (Fraser et al. (2012).
These postflight changes were somewhat less than expected based on short-duration flights and early reports of long-duration missions and suggest that the current countermeasures on the ISS with the latest exercise equipment and new training regimens are keeping cardiovascular control mechanisms well prepared for return to Earth (Hughson et al. 2012).
Studies have shown a consistent impairment of dynamic cerebrovascular autoregulation and CO2 reactivity in astronauts chronically exposed to elevated atmospheric CO2 from long-duration space flight; however, there were between-person differences in the magnitude of impairment. Evidence also suggests possible cerebrovascular consequences, such as thickening of the cerebral arteries, from prolonged elevation in cerebral blood pressure. It is unclear at the moment whether these changes have pathophysiological significance associated with the complications in vision attributed to increased intracranial pressure. Future studies should investigate in-depth pre- to postflight changes in cerebral blood flow and CO2 reactivity to determine whether they are predictors of health complications resulting from long-duration space flight (Zuj et al. 2012).
Fraser KS, Greaves DK, Shoemaker JK, Blaber AP, Hughson RL. Heart Rate and Daily Physical Activity with Long-Duration Habitation of the International Space Station. Aviation, Space, and Environmental Medicine. 2012; 83(6): 577-584. PMID: 22764612.
Hughson RL, Shoemaker JK, Blaber AP, Arbeille P, Greaves DK, Pereira, Jr. PP, Xu D. Cardiovascular regulation during long-duration spaceflights to the International Space Station. Journal of Applied Physiology. 2012; 112(5): 719-727. PMID: 22134699.
Zuj KA, Arbeille P, Shoemaker JK, Blaber AP, Greaves DK, Xu D, Hughson RL. Impaired cerebrovascular autoregulation and reduced CO2 reactivity after long duration spaceflight. American Journal of Physiology: Heart and Circulatory Physiology. 2012; 302(12): H2592-H2598. DOI: 10.1152/ajpheart.00029.2012. PMID: 22492717.
Shoemaker JK, Hughson RL, Sinoway LI. Gender affects sympathetic neurovascular control during postural stress. Journal of Gravitational Physiology. 2002; 9: P83-P84.
Sigaudo-Roussel D, Custaud M, Maillet A, Frutoso J, Guell A, Kaspranski R, Hughson RL, Gharib C, Fortrat JO. Heart rate variability after prolonged spaceflights. European Journal of Applied Physiology. 2002; 86: 258-265.
Hughson RL, Shoemaker JK, Topor ZL, Edwards MR, O-Leary DD, Lin DC, Gelb AW. Optimizing an LBNP protocol to test cardiopulmonary and arterial baroreflex control of vascular resistance. Journal of Gravitational Physiology. 2002; 9: P73-P74.
O-Leary DD, Shoemaker JK, Edwards MR, Hughson RL. Spontaneous beat-by-beat fluctuations of total peripheral and cerebrovascular resistance in response to tilt. American Journal of Physiology: Heart and Circulatory Physiology. 2004; 287: R670-R679.
Hughson RL, Shoemaker JK. Vascular health in space. Journal of Gravitational Physiology. 2004 Jul; 11(2): P71-P74. PMID: 16235421.
Hughson RL, Shoemaker JK, Arbeille P, O-Leary DD, Pizzolitto KS, Hughes MD. Splanchnic and peripheral vascular resistance during lower body negative pressure (LBNP) and tilt. Journal of Gravitational Physiology. 2004; 11: P95-P96.
Edwards MR, Topor ZL, Hughson RL. A new two-breath technique for extracting the cerebrovascular response to arterial carbon dioxide. American Journal of Physiology: Heart and Circulatory Physiology. 2003; 284: R853-R859.
Hughson RL, O-Leary DD, Shoemaker JK, Lin DC, Topor ZL, Edwards MR, Tulppo MP. Searching for the vascular component of the arterial baroreflex. Cardiovascular Engineering. 2004; 4: 155-162.
Blaber AP, Goswami N, Bondar RL, Kassam MS. Impairment of Cerebral Blood Flow Regulation in Astronauts With Orthostatic Intolerance After Flight. Stroke. 2011; 42: 1844-1850. DOI: 10.1161/STROKEAHA.110.610576.