What do living in outer space and being a couch potato have in common? Both can have similar effects on the human body, and both are the subject of research by Dr. Richard Hughson, a cardiovascular exercise physiologist and Professor in the Department of Kinesiology at the University of Waterloo.
A one-time marathon runner who placed third in the 1979 Pan-Am Games, Dr. Hughson turned his long-time interest in sports and science into a career exploring the mechanisms responsible for adapting to the stress of physical activity and changes in posture at the University of Waterloo, where he supervises the Cardiorespiratory and Vascular Dynamics Laboratory. His focus is the adaptation of the heart and blood vessels to new environments such as outer space.
"In outer space, accomplishing tasks requires little physical work because the body doesn't have to work against gravity," says Hughson. "So the body's response to zero gravity resembles what happens with a lack of exercise."
The body compensates for zero gravity by reducing blood volume, while the reflexes that control the heart and blood vessels become less efficient. This increases the possibility of fainting and dizziness upon return to Earth. Transitions between lying down and an upright posture also have similar effects on the cardiovascular system.
"Our research has applications for astronauts, athletes, and people who experience dizziness or fainting, thought to be a major cause of falls among the elderly," says Hughson. "There should be parallels between a stay in space and the aging process."
Since 1988, Hughson and his team have studied the effects of bedrest. The subject lies flat on a surface that is tilted so that the head is lower than the feet; this accelerates the body's response and mimics what it's like to be in space. "Without gravity, there is less blood pushed down into the legs. The head-down tilt forces your blood to circulate as if you were in space," explains Hughson.
Hughson's bedrest research has progressed from short-term experiments of four hours to longer term ones. He is part of the Women International Space Simulation for Exploration (WISE), in which participants are confined for two months to bedrest while positioned in a six-degree head-down tilt. This experiment is led by the European Space Agency with NASA and the French Centre national d'études spatiales (CNES).
"As our early research illustrates, a mere four hours of bedrest in a head-down tilt provokes a range of responses, including changes in vein diameter, blood pressure, and blood hormone levels," says Hughson.
"The WISE findings will provide a comparison for experiments we're planning for the International Space Station, currently scheduled for 2007," reveals Hughson. "We're very excited about this because it's an opportunity to compare heart rate and blood pressure responses in astronauts before, during, and after their mission, and eventually determine what astronauts need to do to come back to Earth as healthy as possible."
In October 2005, Dr. Hughson received the University of Waterloo's Award of Excellence in Graduate Supervision. Colleagues and students admire him for creating a rigorous yet nurturing research environment.