THE EFFECT OF LONG-TERM MICROGRAVITY EXPOSURE ON CARDIAC AUTONOMIC FUNCTION BY
ANALYZING 24-HOURS ELECTROCARDIOGRAM (BIOLOGICAL RHYTHMS)
Research Area: Cardiovascular and Respiratory Systems
Expedition(s): 18- 29
Principal Investigator(s): ● Chiaki Mukai, MD, PhD, Japan Aerospace Exploration Agency,
Tsukuba, Japan
RESEARCH OBJECTIVES
The Effect of Long-term Microgravity Exposure on Cardiac
Autonomic Function by Analyzing 24-hours
Electrocardiogram (Biological Rhythms) examines the effect
of long-term microgravity exposure on cardiac autonomic
function by analyzing 24-hour electrocardiogram of long-
duration International Space Station (ISS) crew members.
EARTH BENEFITS
The crew health care technology for the biological rhythm
disruption during spaceflight provides the general public
with useful hints to promote a healthy daily lifestyle.
SPACE BENEFITS
Monitoring cardio autonomic functions is important for improving crew health technology
during long-duration spaceflight.
RESULTS
Three Data collection periods of ECG readings using the Digital Holter ECG aboard the ISS were
conducted to provide trends for long-duration, microgravity exposure. Over 24 hours, the
average main (large heart pulse) RR interval periods were kept almost within circadian range.
The circadian rhythm contained in RR intervals was significantly stronger in the latter period
than in the early and middle periods. The study of circadian rhythm on RR intervals in a
microgravity, long-duration environment will be analyzed to assist astronauts in the recovery of
normal circadian rhythms in a prolonged space stay in the future.
PUBLICATION(S)
Yamamoto N, Otsuka K, Kubo Y, et al. Effects of long-term microgravity exposure in space on
circadian rhythms of heart rate variability. Chronobiology International. November 13, 2014;1–
14.
This investigation is complete; however additional results are pending publication.
Ground test subject with Holter attached
to collect ECG data. JAXA image.