Space Cycle May Tackle Risks of Microgravity

by Chris Bergin

Astronauts embarking on missions to the Moon, Mars and beyond may return home in excellent health, well-protected from serious bone and muscle loss, two of the most debilitating effects of prolonged weightlessness.

A new kind of fitness machine, being developed by the National Space Biomedical Research Institute, through researchers at the University of California – Irvine, is developing a bicycle-driven centrifuge that allows space explorers to perform resistance-training exercises under Earthlike gravity.

Called the Space Cycle, the machine is actually a two-person mini-gym. One rider pedals the cycle, spinning the centrifuge to a rotation rate that can generate up to five times the Earth’s surface gravity. The other rider, suspended opposite the cycler, stands on a platform, and while holding onto vertical support bars, performs squats.


While one rider drives the Space Cycle, both benefit from resistance-training under gravity, essential to maintaining healthy bone and muscle mass, as well as an essential level of cardiovascular fitness.


“The Space Cycle is an artificial gravity exercise gym”, observes Dr. Vincent J. Caiozzo, PhD., a researcher on the NSBRI’s “Muscle Alterations and Atrophy Team,” whose studies over the past year have led to this breakthrough machine. “The platform can be fitted with a treadmill, bike or any kind of exercise equipment and provides an environment for exercise under normal, Earth-like loading conditions.”


The team receives about $2.5 million in annual funding from NASA.


It has long been understood that prolonged exposure to microgravity results in weakening of the cardiovascular, muscular and skeletal system. Living under microgravity for one year can result in muscle and bone loss rates of up to 25 and 30 percent, respectively.


Humans may suffer similar effects after extended periods of time on the Moon and Mars, which have surface gravities at 17 and 38 percent that of Earth’s, respectively.


“The novelty of artificial gravity resistance training is that each element of the body is loaded proportionally. Leg muscles can be made to work against high loads without the need for external weights, which is important in light of the limited mass and space available on missions,” said Caiozzo.



Toward an Advanced Space Medicine


The Space Cycle is itself a product of a joint effort by NASA and the NSBRI to develop and test advanced space medical technologies and training programs for flight surgeons to diagnose and treat medical conditions that arise in space flight. That effort was the answer to a call made in President Bush’s Space Exploration Initiative in early 2004.


“The United States will launch a re-focused research effort on board the International Space Station to better understand and overcome the effects of human space flight on astronaut health, increasing the safety of future space missions,” said the President on January 14, 2004, during his Vision for Space Exploration Speech.


The NSBRI, based in Houston, TX on the campus of the Baylor School of Medicine, is playing the leadership role in an effort by allied institutions to overcome the health risks that humans will face on years’ long missions to Mars and the other planets.


“One of the major problems we are going to have to overcome with space travel are the limitations of the human body, such as radiation in space, the isolation of long-term space flight, just about every system of the body,” remarked Dr. David Hilmers, a retired astronaut and Baylor professor of internal medicine and pediatrics. “The realization of the goals that President Bush outlined with his space initiative will make it incumbent upon us to solve these problems. This underscores the importance of the research that is being done at Baylor College of Medicine and the NSBRI”.


In February of that year, Dr. Kenneth Baldwin, a UC-Irvine colleague of Caiozzo’s, was chosen by NASA to oversee the “Muscle Alterations and Atrophy Team”.  


“If we truly want to send humans to Mars, we need to address the physiological problems extended space travel presents,” remarked Baldwin, a professor of biophysics and physiology. “Research funded by the institute will play a key role with overcoming the physical limits astronauts currently face”.


That year, Baldwin and Caiozzo were each given a $1.2 million NBSRI grant to pursue two research paths toward space fitness solutions. Baldwin is studying exercise routines to abate muscle atrophy.


Caiozzo, along with two other UC-Irvine researchers, Dr. Jim Hicks and Dr. Joyce Keyak, are continuing the team’s work on the Space Cycle, based on a prototype they helped create in the 1990s.

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