NASA Space Technology Reports - Astronaut Health and Medical Issues, Long-Duration Mission Countermeasures, Cancer, Mental Health, Dental, Injuries and Illness, Training, Carbon Dioxide by unknow

Author:unknow
Language: eng
Format: epub
Publisher: Progressive Management
Published: 2013-08-08T00:00:00+00:00

Evolution has favored individuals able to work effectively in group settings. As such, we view instances of social isolation as threatening (i.e., a cue for the stress response) and seek socialization as a means of survival (Cacioppo & Patrick, 2008). In an ICE environment, there will be limited individuals with whom to interact. Crew members will be limited to physical contact with only the other crew members and just verbal communication with those on Earth. Furthermore, connections with important others such as spouses, children, and friends will be extremely limited.

Stress is the undesirable outcome of sensory deprivation and social isolation that we are attempting to mitigate. Increased stress causes numerous physiological and psychological maladaptations to the individual. Usually, individuals have opportunities to "decompress" by removing themselves from stressful situation so that they can distance themselves from the source of stress and rejuvenate. Astronauts in a long-duration space flight will not have the ability to create the necessary distance from sources of stress to heal, so stress will continue to build over time without an outlet. As such, providing these outlets in the form of countermeasures allows for better performance and well-being in the individuals.

Stress, both chronic and acute, has been linked to a wide variety of physiological and psychological outcomes. Physiological changes to the neural structure of the brain are evident in the research, such as the over-functioning of the stress-response systems that have been described by Lederbogen and colleagues (2011). Stress affects the hypothalamic-pituitary-adrenocortical axis, particularly through the production of cortisol, and the sympathetic-adrenal-medullary system through the release of catecholamines (Cohen, Janicki-Deverts, & Miller, 2007). These activations, in turn, mediate the relationship between stress and outcomes such as depression, cardiac disease, and autoimmune diseases. Within the brain, hippocampal shrinkage in the size and number of neurons occurs in individuals with mood disorders and prolonged stress (Otto, 2007). Additionally, the number of terminals and branches within the neuron available to make connections with other neurons decreases. Furthermore, under adverse conditions, the brain stops producing new neurons, termed neurogenesis. In cases of sensory deprived environments, neurogenesis does not occur, simply because the brain is not stimulated (Otto, 2007).

The psychological outcomes of prolonged stress include a buffet of negative affective, behavioral, and cognitive outcomes. As described by Cohen and colleagues, physiological changes associated with chronic stress are related to depression (Cohen et al., 2007). Additional research has linked chronic stress to anxiety and insomnia, among other mood disorders (Otto, 2007). While most mood disorders found in individuals in ICE environment occurs at a lower rate than the normal population, the potential outcomes of major mood disorders in an ICE environment could have more detrimental consequences (Stuster, 2010; Suedfeld & Steel, 2000).

Studying ICE Environments

Because living in space is a unique experience, there are no perfectly transferable studies that can predict the impact of long-duration space flight on human health and psyche. Instead, we use several types of analogues to construct a picture of what might occur. These analogues include, but are not limited

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