Space tours make bones brittle

Washington: Astronauts who spend months in space tend to lose bone strength, making them increasingly vulnerable to fractures in later life.
    Universities of California (UC) Irvine and San Francisco evaluated 13 astronauts who spent four to six months on the International Space Station and found that, on average, their hipbone strength decreased by 14%.
    Three astronauts experienced losses of 20% to 30%, rates comparable to those seen in older women with osteoporosis.
    These results alarmed researchers because they revealed a greater rate of bone deterioration than previously measured using less powerful technologies.
    Orthopaedic researchers looking into the effects of long-duration spaceflight usually study the hipbone or spine. The hip experiences the greatest rate of bone loss in space, and a hip fracture almost always requires hospitalisation and major surgery.
    It can impair a person's ability to walk unassisted and may cause prolonged or permanent disability or even death. Fractures of the vertebra also have serious consequences, including loss of height, severe back pain and deformity.
    "If preventive measures are not taken, some of our astronauts may be at increased risk for age-related fractures decades after their missions," said Joyce Keyak of UC Irvine, biomedical engineering professor, who led the study.
    For as long as there have been astronauts, researchers have studied why the microgravitational environment of space makes bones more fragile. While previous studies looked at bone mineral density, this study is the first to specifically evaluate bone strength.
    Keyak and her colleagues used a novel computer programme she developed over the past 20 years to identify hipbone fracture risk in people with osteoporosis. The study team used this programme to analyse structurally the hipbone CT scans of one female and 12 male International Space Centre crewmembers, said an UCI release.
    To lessen the effects, space station astronauts must exercise at least two hours every day and undergo weeks of rehabilitation after their return to Earth. IANS
HEALTH HAZARDS
Long periods in space make astronauts vulnerable to a wide range of health risks

    Exposure to weightlessness affects the body upon return to gravity's pull. Muscles, heart function, blood flow, red blood cell production and the immune system are weakened when astronauts first step back onto Earth

    The common ailments are nausea, anaemia, lethargy, headaches, disorientation, fatigue, depression, motion sickness, heart palpitations, weakened defences against infectious disease and losses of blood volume, muscle mass and bone density

    In space, the loss of bone mineral is alarming. It occurs at the rate of 1% to 1.5% a month, especially from the hip and lower spine. This sharply reduces bone strength, leading to fractures in later life

    Some astronauts experience losses of 20 to 30%, rates comparable to those seen in older women with osteoporosis

    Atrip to Mars, a year or two each way, carries the risk of leaving an astronaut crippled upon return to Earth

    The best way to keep healthy is to go for strenuous exercises for at least two hours a day to build muscles during the space odyssey, and to undergo weeks of rehabilitation on return, say experts