NASA is looking for people willing to spend a month in bed, as part
of a study of how long-term space flight affects the human body.

The upcoming study, which will begin in January 2002, will require
that volunteers lie in beds tilted head-down at a six-degree angle
for 30 days, 24 hours a day. Bed rest in the six-degree head-down
tilt position is considered the best Earth model to simulate the
effects of prolonged microgravity on the human body.

“Head-down bed rest simulates weightlessness and induces many of the
physiological changes similar to those seen with space flight,” said
Fritz Moore, Ames’ project manager for the Countermeasures Evaluation
and Validation Project (CEVP). “These effects include cardiovascular
deconditioning, muscle atrophy, decreased bone strength, and shifts
in fluid and electrolyte balance,” he explained.

The goal of the project, which is managed by NASA’s Johnson Space
Center in Houston, is to sponsor space flight and ground-based analog
campaigns that facilitate evaluation of promising countermeasures for
future flight validation. A countermeasure is a drug, exercise or
other intervention that minimizes the changes that occur during space
flight and that impede normal functioning after people return to
Earth. Ames manages the facility where the bed rest studies are
carried out.

Male and female volunteers between the ages of 25 and 55 are needed
for the study. Candidates must be non-smokers in good health and not
participating in a highly competitive or rigorous exercise program.
They should have no history of cardiovascular or musculoskeletal
disease or hernia. Female volunteers must not be pregnant.

Participants will be housed in Ames’ Human Research Facility for 45
days. They will lie in bed for 30 of those days. In addition to bed
rest, these studies will involve a standardized battery of integrated
physiological and cognitive tests called the Integrated Testing
Regimen (ITR). These tests measure changes in physical and mental
performance before, during and after bed rest. Currently many of
these tests are performed on astronauts before and after space flight
to measure the changes caused by extended space travel.

“This regimen tests many physiological systems and will be used to
evaluate the efficacy of medical interventions for specific problems
that occur during space flight,” said Moore. The majority of the
tests will be conducted in Ames’ Human Research Facility and Human
Exercise Laboratory using both traditional and special physiological
test equipment.

Most of the changes that occur during space flight are a normal
acclimatization to the space environment, Moore explained. A
successful countermeasure limits this acclimatization, so the
astronauts can return to Earth without any persistent physiological
or psychological impairments.

The first countermeasure to be tested is a regimen of resistance
exercises performed with a machine called the interim Resistive
Exercise Device (iRED). The iRED exercise regimen will be compared
with a no-exercise regimen to determine which is more effective at
preventing losses in muscle volume and strength, as well as losses in
bone mineral density that occur during bed rest. Testing will occur
both before, during and after volunteers have undergone 30 days of
bed rest at the six-degree downward tilt.

Participants, who will be employed as part-time, temporary employees
of a NASA contractor, will be required to refrain from alcohol and
caffeine consumption for the duration of the study. Limited overnight
fasting also will be required at times. Certified personnel will draw
blood samples. A medical monitor will be present, along with
certified equipment and test operators, during maximal exertion
testing. A thorough medical examination will be provided to verify
the health status of all selected volunteers.

This study has been reviewed and approved by the institutional review
boards at Ames and at the Johnson Space Center.

For more information about becoming part of this space
station-related study, contact Heather Wilson at (650) 604-5551, or
e-mail: hwilson@mail.arc.nasa.gov.