A new study indicates that a simple regime that keeps returning astronauts from fainting could help earthbound patients suffering from a similar condition. Led by Benjamin Levine, a professor of exercise sciences at UT Southwestern Medical Center and director of the Institute for Exercise and Environmental Medicine at Texas Health Presbyterian Hospital in Dallas, the research examines how to overcome the effects on blood pressure due to long-term space missions.
It seems that the more time astronauts spend in space the more ways we find the environment beyond our atmosphere is detrimental to the human body. Long duration missions aboard space stations have shown that zero gravity can reduce muscle mass, weaken bones, impact the cardiopulmonary system, cause blurred vision and sinus problems, and even harm the immune system.
Another problem is that astronauts who spend a long time in space suffer from fainting spells and dizziness after they return to Earth. This condition is known as orthostatic hypotension, which is a temporary drop in blood pressure. It's what sometimes happens when you stand up too quickly and the blood rushes from the brain to the feet, making you feel giddy or even pass out.
According to the American Heart Association, it's also a condition that affects patients who have been bedridden for a long time or suffer from certain cardiac conditions. Because of this, the mystery of the fainting astronauts is of particular interest to medical science.
For the new study, eight male and four female astronauts aboard the International Space Station (ISS) who were on six-months or longer tours of duty were equipped with portable monitors that took measurements of their heart rate and blood pressure 24 hours a day for six months.
During this time, the astronauts carried out two hours a day of endurance and resistance exercises to offset cardiovascular, bone, and muscle deterioration. On returning to Earth, they were given an intravenous treatment of saline solution.
The scientists found that for the critical 24 hours after returning to terra firma, none of the astronauts were dizzy or experienced fainting during normal activities. However, the researchers say that they would prefer to do more tests with a larger pool of astronauts, including those on longer missions, and more work on how much of the exercise or saline regime are actually needed for positive results, or whether the blood pressure stabilization occurs without them.
"Understanding the physiology of spaceflight can be helpful for understanding many conditions experienced by non-astronauts," says Levine. "As we prepare to celebrate the 50th anniversary of the Apollo 11 moon landing, it's exciting to think of how our exploration in and of space can lead to important medical advances here on Earth."
The research was published in Circulation.
Source: American Heart Association
