Article

The aim of this study was to examine whether autonomic modulation of
heart rate as measured by heart rate variability and heart rate complexity at
rest and during static handgrip exercise differs between individuals with and
without paraplegia. This study also examined the relationships between heart rate
complexity and heart rate variability parameters.
DESIGN: Heart rate variability
and complexity were evaluated in 20 individuals with paraplegia and in 20
individuals without paraplegia during 3 mins of rest and 2 mins of static
handgrip exercise at 30% of maximum isometric strength. Spectral decomposition of
heart rate variability was used to obtain total power, power in low-frequency and
high-frequency ranges, and the ratio of low- to high-frequency power. Heart rate
complexity was quantified with sample entropy, a measure of irregularity of the
beat-to-beat time series. RESULTS: Sample entropy was lower (P < 0.05) at rest
and during exercise in participants with paraplegia. Total, high-, and
low-frequency powers as well as the ratio of low- to high-frequency power did not
differ between groups. Sample entropy did not significantly correlate with low-
and high-frequency powers or their ratio. CONCLUSIONS: Individuals with
paraplegia show lower heart rate complexity at rest and during static exercise.
This finding may have implications for cardiovascular morbidity in persons with
paraplegia. Heart rate complexity may provide unique information regarding
cardiac autonomic modulation, different from that provided by traditional heart
rate variability measures.

Langue : ANGLAIS