Astronauts are the unique population of physically and mentally fit individuals who have to travel from gravity to microgravity and back to gravity. This force of gravity has major influence on musculoskeletal, neuro-vestibular, cardiovascular and pulmonary systems.
In a microgravity environment, because of reduced loading stimuli, there is increased bone resorption and no change in or possibly decreased bone formation, leading to bone mass loss at a rate of about ten times that of osteoporosis.
- Short Space Flight - a flight of one to fourteen days is considered Short flight.
- Long Space Flight - more than two weeks is considered a long flight.
Physiotherapy plays a very important role in the entire journey starting from Stress relief before and during the flight, Post-flight support and rehabilitation and Counteractingin-flight symptoms an also assisting the astronauts with their entire stay in the Space Station with the help of a carefully drafted exercise regime.
This is what happens to the astronaut’s body in Space–
- Brain– Cosmic Radiation, Insomnia, Stress and trying to re-orient the body balance system.
- Spine– Astronauts are taller in Space! The space between the vertebrae expands due to zero / microgravity.
- Heart– In Space Hearts don’t have to work as hard to pump the blood around the body. So eventually it may shrink, which can cause problems for astronauts when they re-enter Earth.
- Muscles– In Space, Muscles aren’t really needed to hold up the body. Over time, they become weaker and deteriorate. Astronauts must exercise every day to prevent this from happening. While during the space flight there is reduced ground reaction force resulting in reduced loading and disuse of weight-bearing structures. This results in muscle atrophy and bone demineralization. Muscle atrophy causes alteration in muscle strength thereby affecting the muscle function. Bones – Like our muscles, bones aren’t needed much in microgravity. Without exercise, they deteriorate and become weak and brittle. Bone demineralization results in altered calcium metabolism and altered level calciotropic hormones. Bone mineral loss accounts for about 4 % in the weight-bearing bones, the magnitude of which is dependent on the length of the exposure to the light.
- Blood– Blood is normally pulled towards our feet by gravity. But in space, the blood and fluid is pulled towards thoraco-cephalic region giving astronauts puffy faces.
With technologies developing in leaps and bounds, effective countermeasure strategies like optimal exercise training are required to minimize the spaceflight is potentially harmful deconditioning effects on the astronaut's physiological function, performance and overall health due to microgravity. Thus exercise training preferably prescribed by a Physical Therapist is one of the essential components for the rehabilitation of astronauts. Yoga practice may provide options that can be added to an astronaut’s personal health kit. Breathing and mental practices may in themselves be used as powerful stress management. A variety of Yoga body postures or poses (called āsana_s) and Yoga breathing exercises (prānāyāma_s) combined with finger-thumb hand gestures (mudrā_s), are claimed to provide stress relief and many other health benefits.