View source for Astronaut physiology


== Definition ==
Space physiology is the study of the effects of space travel on the human body. It is a subfield of space medicine that focuses on the physiological changes that occur in the body during spaceflight.<ref>Barratt MR, Pool SL (eds). (2008) Principles of Clinical Medicine for Space Flight. Springer, New York.</ref>

== Effects of Microgravity on the Body ==
Microgravity, or weightlessness, has a profound impact on the human body. In space, the body does not have to work as hard to maintain posture and movement, which can lead to a range of effects, including:

* '''Muscle atrophy''': Prolonged exposure to microgravity can cause muscles to weaken and shrink, particularly in the lower body.<ref>Convertino VA, Sandler H. (1995) Effects of microgravity on the musculoskeletal system. In: Fregly MJ, Blatteis CM (eds) Handbook of Physiology: Environmental Physiology.</ref>
* '''Bone loss''': In microgravity, the body does not have to work as hard to maintain bone density, leading to a loss of bone mass, particularly in the weight-bearing bones of the lower body.
* '''Fluid shift''': In microgravity, fluids in the body shift towards the upper body, leading to puffy faces, congested sinuses, and other issues.
* '''Cardiovascular changes''': Microgravity can cause changes in blood pressure, cardiac output, and vascular resistance.<ref>Smith JJ, Porth CM. (1991) Posture and the circulation: the physiology and pathophysiology of orthostasis. Journal of Clinical Pharmacology, 31(5): 444-451.</ref>

== Other Effects of Space Travel on the Body ==

In addition to the effects of microgravity, space travel can also cause a range of other physiological changes, including:

* '''Radiation exposure''': Space travelers are exposed to higher levels of cosmic radiation, which can increase the risk of cancer and other health problems.<ref>Durante M, Cucinotta FA. (2008) Heavy ion carcinogenesis and human space exploration. Nature Reviews Cancer, 8(6): 465-472.</ref>
* '''Sleep disturbances''': The unusual environment of space can disrupt sleep patterns, leading to fatigue and other issues.
* '''Immune system suppression''': Space travel can weaken the immune system, making astronauts more susceptible to illness.
* '''Vision impairment''': Prolonged exposure to microgravity can cause changes in the shape of the eye, leading to vision problems.

== Adaptation to Space Travel ==

Astronauts undergo a range of physiological changes as they adapt to space travel. These changes can include:

*[[Orthostatic intolerance]]: Astronauts may experience dizziness and lightheadedness when standing up after prolonged periods in microgravity.
*[[Space adaptation syndrome]]: Astronauts may experience a range of symptoms, including nausea, vomiting, and disorientation, as they adapt to the microgravity environment.

== Countermeasures ==

To mitigate the effects of space travel on the body, astronauts use a range of countermeasures, including:

* '''Exercise''': Regular exercise can help maintain muscle mass and bone density.
* '''Resistance bands''': Resistance bands can be used to provide resistance and help maintain muscle strength.
* '''Lower body negative pressure''': Lower body negative pressure (LBNP) devices can be used to simulate the effects of gravity on the lower body.
* '''Sleep schedules''': Astronauts follow strict sleep schedules to help regulate their sleep patterns.

== See Also ==
*[[Space medicine]]
*[[Space adaptation syndrome]]
*[[Orthostatic intolerance]]
*[[Radiation exposure]]
*[[Space adaptation syndrome]]

== External Links ==
* [https://www.nasa.gov/hrp/bodyinspace NASA's Human Research Program]
* [https://www.esa.int/Science_Exploration/Human_and_Robotic_Exploration/Human_Physiology_in_Space European Space Agency's Human Physiology in Space]
* [https://www.nsbri.org/research/physiology/ National Space Biomedical Research Institute's Space Physiology]

== References ==
<references/>

[[Category: Space Medicine]]