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EXPERIMENT INFORMATION

Identification of Cardiometabolic Vulnerabilities Caused by Effects of Synergistic Stressors Commonly Encountered during Space Missions (NNX10AR10G)
Principal Investigator
Research Area:
Biomedical countermeasures
Cardiovascular physiology
Species Studied
Scientific Name: Homo sapiens Species: Human

Description
OBJECTIVES:
Microgravity affects cardiovascular (CV) function by decreasing circulating blood volume and central venous blood pressure and increasing stroke volume and cardiac output, potentially leading to cardiac rhythm disturbances, which have been documented during space flight On top of this, astronauts experience additional CV stress, for example, during space walks or robotic operations during Extravehicular Activities (EVAs). In addition, during any space mission, astronauts experience unusual light-dark cycles leading to some degree of chronic circadian disruption which can take the form of: (a) the whole body being at the ‘wrong time’ given the prevailing behaviors. For example, astronauts are often awake, eat, and perform activities at the time when their internal biological clocks are preparing the body for optimal physiological rest and sleep; or they may be trying to sleep during the biological day when their circadian clock normally prepares the body for activities; or (b) parts of the body can be set to suboptimal times, such ‘internal desynchrony’ when varied cells and organs are shifting to new time zones at different rates. Thus, circadian disruption may result in maladaptive physiological responses. In addition, the inevitable sleep loss that accompanies circadian disruption itself can further stress the CV system. Undoubtedly, mission requirements, such as ‘slam shifting’ before EVAs and working extended shifts during EVAs will contribute to sleep loss. The environmental conditions on the International Space Station (ISS), such as noise, and heat, also contribute to sleep loss.

Cardiac arrhythmias have been observed in astronauts and are considered a major risk endangering the success of space missions. In addition to structural changes, such arrhythmias can be triggered by numerous interacting and summating stressors such as exercise, sleep loss, working during the biological night, causing changes in cardiovascular risk markers, such as increased blood pressure, cardiac vagal withdrawal, sympathetic activation, and promotion of hemostatic mechanisms. While such responses can be vital homeostatic responses to such challenges, chronic activation of these mechanisms, or activation in individuals with underlying can be counterproductive and lead to adverse cardiovascular events, including stroke or myocardial infarction. This study had the following specific aims:

  1. The effect of circadian disruption on CV function, including the CV responses to physical and mental challenges commonly encountered during space flight.
  2. The effect of sleep loss on CV function, including the CV responses to physical and mental challenges commonly encountered during space flight.
  3. The synergetic effects of circadian disruption plus sleep loss on CV function, including the CV responses to physical and mental challenges commonly encountered during space flight.


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Keywords
Actigraphy
Circadian rhythm
Echocardiography
Exercise
Lighting
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Data Information
Data Availability
Archive is complete. Data sets are not publicly available but can be requested.
Data Sets+ Request data

Parameters
Activity
Alertness
Blood pressure, diastolic
Blood pressure, systolic
Cardiac function
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Mission/Study Information
Mission Launch/Start Date Landing/End Date Duration
Ground 05/01/2009 In Progress

Human Research Program (HRP) Human Research Roadmap (HRR) Information
Crew health and performance is critical to successful human exploration beyond low Earth orbit. The Human Research Program (HRP) investigates and mitigates the highest risks to human health and performance, providing essential countermeasures and technologies for human space exploration. Risks include physiological and performance effects from hazards such as radiation, altered gravity, and hostile environments, as well as unique challenges in medical support, human factors, and behavioral health support. The HRP utilizes an Integrated Research Plan (IRP) to identify the approach and research activities planned to address these risks, which are assigned to specific Elements within the program. The Human Research Roadmap is the web-based tool for communicating the IRP content.

The Human Research Roadmap is located at: https://humanresearchroadmap.nasa.gov/

+ Click here for information of how this experiment is contributing to the HRP's path for risk reduction.

Additional Information
Managing NASA Center
Johnson Space Center (JSC)
Responsible NASA Representative
Johnson Space Center LSDA Office
Project Manager: Pamela A. Bieri
Institutional Support
National Aeronautics and Space Administration (NASA)
Proposal Date
10/01/2010
Proposal Source
2009 Crew Health NNJ09ZSA002N