The most important 'cosmic' malady of space travel is motion sickness, or 'space adaptation syndrome'. Its primary symptoms are nausea, sweating, headache, appetite loss, lethargy, dizziness, notorious vomiting spells and cold fingers. With such a spectre being the 'song of one's burden' in space, it is, indeed, valiant of astronauts to be able to generate cheerful smiles on TV
Yuri Gagarin waxed eloquent about how wonderful things were up there without the comforting force of gravity. A 'falling-elevator' sensation – where the spine expands, albeit temporarily. This leads to disconcerting backaches.
Interestingly, when astronauts return from space they are a few inches 'taller' too by as much as 2.75 inches.
There are other changes– bizarre and complex– from bones that have become lighter and blood cell chemistry gone askew, primarily because of 'distorted' immune function, cardiac arrhythmia and 'reduced' size of the heart itself.
Though there is no precise elucidation for such changes, space physiologists relate it to prolonged exposure to zero-gravity, or 'weightlessness'.
The most important 'cosmic' malady of space travel is motion sickness, or 'space adaptation syndrome'.
Its primary symptoms are nausea, sweating, headache, appetite loss, lethargy, dizziness, notorious vomiting spells and cold fingers. With such a spectre being the 'song of one's burden' in space, it is, indeed, valiant of astronauts to be able to generate cheerful smiles on TV.
The precise source of motion sickness is physical –it is inferred that the queasy malady could be the fallout of a state of chaos in the inner ear's vestibular system, the body's balancing apparatus. This complex part in the inner ear probably tells the brain that the body is tilting, while the senses of sight and touch say it is not. When astronauts are on solid ground, the constant tug of gravity tells them of the 'up-anddown' sides of things without riddles attached. In zero-gravity, such a sense of subtle perception is often lost. This axiom does not, of course, hold good for those exhilarating rides in the amusement park, where gravitational cues get befuddled.
Motion sickness for most astronauts usually dissipates in a few days' time, as the brain adapts itself to conditions of zero-gravity.
However, other effects of the state don't disappear with ease. This is what happens– on planet earth, blood and body fluids pool marginally in the lower torso and the legs under the effect of gravity, even though the dissipation is unequal. During space travel, the fluids spread more effectively into the upper extremities. As a result, there is a strange sensation of fullness in the head, juxtaposed by puffed-up eyes and stuffy sinuses.
Muscle-wasting is also common after a trip into the great blue yonder. The legs, for example, shrink palpably. Most annoyingly, there is fluid shift with fluid loss through amplified urination, because the pressure monitoring sensors in the chest take note of surplus fluid and shunt it away. Blood volume too drops within hours of takeoff, leading to dehydration.
As one NASA physiologist put it, "The body's baroreceptors, the pressure-monitoring nerves in the arteries of the chest and neck say, 'Hey, there's too much of fluid in here. We've got to dump the excess.'"
So far, no permanent negative effects from fluid shift have resulted from a voyage in space. However, the transition back to gravity does have a bearing.
Once on earth, astronauts often suffer from sudden changes in blood pressure levels. In space, such fluctuations can impair the body's blood-pressure-regulating reflex, causing variations identical to those that occur in 'earth-bound' individuals prior to heart attacks.
With lack of blood, the heart is not always in a position to pump enough oxygen-carrying fluid to the brain. The outcome is severe vertigo and fainting spells, as the newly returned astronaut tries to take their first few 'faltering' steps, or rise from bed.
One simple solution that works is taking large quantities of water and salt tablets before re-entry – to increase blood volume by 15 per cent. However, this uncomplicated solution is effective only for short-term missions.
Man's ingenuity has, of course, found effective means to dealing with such complexities. Space physiology is today increasingly sophisticated –coalescing ideas of novelty with technological progress. New exciting projects are nothing short of the astounding – they have made space odysseys all the more exciting, while expanding on augmented safety parameters vis-à-vis one's health and wellness.
To highlight an example – picture this NASA 'gadget', special and practical, in the form of lower body negative pressure device (LBNP). The unit is a sort of reverse iron-lung system, which applies a partial vacuum to the astronaut's lower torso and limbs, so much so that it sucks fluid back down from the head and chest, redistributing it quite normally through the body. The use this handy 'space suit' in simulators and, at intervals, during space flights, often 'reminds' the astronaut's psyche of earth and gravity.
So far, so good. Yet, the problem area is the circulatory system. It may be fairly easy to correct fluid pressure, but not the body's natural pump – a weightless astronaut's cardiac system would never be able to work as forcefully and articulately as it does on earth. Without gravity, the heart begins to relax, adapting to its lowered work load and more shrivelled existence. Fortunately, the dilemma of reduced heart size is, more or less, self-correcting, once the astronaut returns to their natural dwelling. A majority of astronauts regain their pristine cardiac mass within 2-3 months of their return to mother earth.
Paradoxically, however, a major dilemma is now 'weighted' on the positive side. No astronaut has, so far, displayed any irreversible illness related to a weakened immune system.
What's more, NASA has 'sculpted' super new tools, despite a fall in its budgetary allocations, including the formulation of an 'artificial gravity' spaceship.
What does this connote? That with emerging new cutting-edge technology, it won't take long to crack some of space physiology's most labyrinthine puzzles on terra firma.
Nidamboor is a wellness physician, independent researcher and author
A version of this article appears in the print on August 26 2021, of The Himalayan Times.