CARDIOVASCULAR HEALTH CONSEQUENCES OF LONG-DURATION SPACEFLIGHT
(VASCULAR)
Research Area: Cardiovascular and Respiratory System
Expedition(s): 21-ongoing
Principal Investigator(s): ● Richard Lee Hughson, PhD, University of Waterloo, Waterloo,
Ontario, Canada
RESEARCH OBJECTIVES
This Cardiovascular Health Consequences of Long-Duration Space Flight (Vascular) research is
performed to determine the impact of long-duration spaceflight on the blood vessels of
astronauts. Spaceflight accelerates the aging process and we must understand this to
determine the need for specific countermeasures. Data will be collected before, during, and
after spaceflight to assess inflammation of the artery walls, and changes in blood vessel
properties and cardiovascular fitness.
EARTH BENEFITS
This experiment will contribute to obtaining a better understanding of the mechanisms that
might contribute to premature ageing of the cardiovascular system and detect early markers of
potential atherosclerosis (condition in which fatty material collects along the walls of arteries)
and inflammation.
SPACE BENEFITS
The expected long-term outcome of this research involves the development of appropriate
countermeasures to prevent astronauts undertaking long-duration spaceflights from
experiencing long-term cardiovascular health problems as a result of their time spent in space.
RESULTS
After 6 months in space, pulse wave transit time was increased while carotid artery
distensibility was significantly reduced (P= 0.03, n= 6). Because walking or jogging for 4 0
minutes a day for 3 months reduces carotid and peripheral artery stiffness in older sedentary
subjects, Vascular investigated whether astronauts who maintained physical fitness exhibited
less change in pulse wave transit time to the finger. Although pulse wave transit time from
preflight to postflight tended to be faster post-flight, there was no relationship to the change in
physical fitness. Multiple factors are speculated to contribute to increased arterial stiffness with
aging, including increased vasoconstrictor or reduced vasodilator factors, structural breakdown
of elastin, accumulation of collagen, vascular smooth muscle cell proliferation, and increased
extracellular matrix cross-linking. Animal models for unloading (spaceflight analogs) indicate
cellular hypertrophy in the middle cerebral artery and increased cross-linkage in major elastic
arteries. The possible roles of these factors related to the increased arterial stiffness with
spaceflight have not been investigated in astronauts, and the Vascular experiment provides
data to test these mechanisms.