The researchers examined the daily activities of astronauts from outer space to help develop treatments for orthostatic intolerance. This condition often causes people to faint due to low blood pressure. ( Robin Higgins | Pixabay )
A new study featuring astronaut activities in space offers better insight into what causes people to suffer from low blood pressure even when standing.
Researchers at UT Southwestern Medical Center examine a condition known as orthostatic intolerance to understand how it affects people and how it can be prevented. They believe they may have found answers to the daily activities of astronauts after they returned from the spacecraft.
What is orthostatic intolerance?
Orthostatic intolerance is a condition in which certain individuals have difficulty staying in an upright position as they stand, according to Baker Heart and Diabetes Institute.
People with OI often feel faint, but they may also experience weakness, the head feels light, the heart palpitates or abnormal sweating, and nausea. Some also have problems concentrating while undergoing the OI episode.
In most cases, OI occurs when people switch from lying to standing. This movement causes blood throughout the body to be dragged to the legs and pelvis due to gravity. Blood flow activates the pressure receptors located in the neck and chest, which, in turn, signals the brain to tell that blood has "gone south".
Usually, the body will react to this by activating the instinct of "fighting or running" in the nervous system. The nerve then releases a nerve transmitter called noradrenalin, causing blood vessels in the legs, stomach, and pelvis to tighten and force blood to fight gravity and move back to the heart.
This whole sequence often occurs in less than one second to keep the body's blood flow and blood pressure stable. This is to ensure that the brain continues to receive a good blood supply even when people switch from lying to standing.
Ways to Prevent Orthostatic Intolerance
For their study, UT Southwestern researchers looked at how astronauts deal with the rigors of spaceflight. They noted how some of the crew could not help but fainted during their return trip to Earth.
The team monitored the health of eight male and four female astronauts while they were carrying out their duties into space. Each participant was given a small blood pressure cuff placed on their finger. The device helps track astronaut's blood pressure and heart rate for several periods 24 hours before, during, and after their space flight.
Once they returned from space, astronauts were given a training regimen, as well as saline shots to help them overcome the effects of orthostatic intolerance. The researchers found that the combination prevented the occurrence of the condition.
"Doing one hour or more of daily exercise is enough to prevent loss of heart muscle, and when combined with receiving hydration when they return, the condition is completely prevented," Dr. Benjamin Levine, a professor of Internal Medicine at Southwest UT and lead researcher in this study.
"We hope to see two-thirds of the space crew fainted. On the contrary, no one has fainted."
Researchers are exploring ways to use treatment to deal with other similar conditions. One such disease is the Tachycardia Orthostatic Postural Syndrome or POTS, which often causes women to suffer from debilitating dizziness.
The research findings of UT Southwestern are shown in the journal Circulation.
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