TITLE:
Heart Rate Variability, Standard of Measurement, Physiological Interpretation and Clinical Use in Mountain Marathon Runners during Sleep and after Acclimatization at 3480 m
AUTHORS:
Ivana Gritti, Stefano Defendi, Clara Mauri, Giuseppe Banfi, Piergiorgio Duca, Giulio Sergio Roi
KEYWORDS:
Heart Rate Variability; Very Low Frequency Fluctuation (VLF,
JOURNAL NAME:
Journal of Behavioral and Brain Science,
Vol.3 No.1,
February
27,
2013
ABSTRACT: Fluctuations in
autonomic cardiovascular regulation during exposure to high altitude may
increase the risk of heart attack during waking and sleep. This study compared
heart rate variability (HVR) and its components during sleep at low altitude
and after 30 - 41 hours of acclimatization at high
altitude (3480 m) in
five mountain marathon runners controlled for diet, drugs, light-dark cycle and
jet lag. In comparison to sea level, RR-intervals during sleep at high altitude
decreased significantly (P 0.001). The
significant increase in sympathetic autonomic cardiovascular modulation at high
altitude protects against excessive oxygen deprivation during sleep. Increases
in R-R intervals can require longer periods of acclimatization at3480 m to mitigate the effects of altitude/hypoxia on sympathetic tone, thus reducing
cardiovascular distress at rest during waking and sleep and probably before
during and after athletic performance at altitude.