CARDIOVASCULAR ADAPTATION TO WEIGHTLESSNESS (RHYTHM)
Research Area: Cardiovascular and Respiratory Systems
Expedition(s): 7, 8
Principal Investigator(s): ● Andre Aubert, Katholieke Universiteit, Leuven, Belgium
● Frank Beckers, PhD, Katholieke Universiteit Leuven, Belgium
RESEARCH OBJECTIVES
Orthostatic intolerance (dizziness) is an indicator of cardiovascular deconditioning (a physical
decline) following microgravity expeditions. Despite many studies, the origin of the
cardiovascular deconditioning syndrome still remains unclear. A better knowledge of
orthostatic intolerance following microgravity is crucial to the health of future space explorers
on long-duration space expeditions.
RESULTS
In this study, the non-linear
dynamical control of heart rate
fluctuations, quantified by the
approximate entropy method, was
demonstrated to be affected
immediately after spaceflight in
orthostatic tolerant cosmonauts.
The difference in approximate
entropy between standing and
supine (lying face up) in baseline
conditions was shown. The
difference in approximate entropy
was not present in the first days
after return to Earth. The
differences between standing and supine position disappeared immediately after spaceflight. If
these changes are part of the mechanism to help maintain orthostatic tolerance, they should be
explored further in the future. Up until now, no methods have been found successful in either
detecting the sudden onset of orthostatic intolerance or even the prediction of it. Therefore,
the exploration of non-linear fluctuations might be of interest in an orthostatic intolerant
population. After 25 days the stand response was again similar to the preflight situation,
indicating that the astronauts recovered rather quickly after their spaceflight. The fact that
even orthostatic tolerant cosmonauts present with changes in non-linear heart rate control
might open possibilities to study these control mechanisms in orthostatic intolerant astronauts.
PUBLICATION(S)
Vandeput S, Widjaja D, Aubert AE, van Huffel S. Adaptation of autonomic heart rate regulation
in astronauts after spaceflight. Medical Science Monitor. January 4, 2013;19:9-17.
Tilt test. ESA image.