Heart rate variability during caregiving and sleep after massage therapy in preterm infants

Abstract

Background: Preterm birth impairs the infant's stress response due to interruption of autonomic nervous system (ANS) development. Preterm infants demonstrate a prolonged and aberrant sympathetic response to stressors. ANS development may be promoted by massage therapy (MT), which has been shown to improve stress response in preterm infants.

Aims: The aim of this study was to compare preterm infant ANS function and stress response during sleep and caregiving epochs, as measured by heart rate variability (HRV), after two weeks of twice-daily MT.

Study design: A subset of participants from a larger randomized, masked, controlled trial was used.

Subjects: Twenty-one infants (8 males and 13 females) from a larger study of 37 medically stable preterm infants were studied. The infants were receiving full volume enteral feedings with a mean post-menstrual age of 31.4 (MT) and 30.9 (control) weeks.

Outcome measures: Low to high frequency (LF:HF) ratio of HRV was the outcome of interest.

Results: There was a significant group×time×sex interaction effect (p<.05). Male control infants demonstrated a significant decline in LF:HF ratio from baseline to the second caregiving epoch, suggesting decreased mobilization of sympathetic nervous system response when exposed to stressors. Male MT infants demonstrated increased LF:HF ratio during caregiving and decreased LF:HF ratio during sleep epochs, suggesting improved ANS function, although this was not statistically significant. LF:HF ratio was similar in female MT and female control infants during caregiving and sleep.

Conclusions: Control males had decreased HRV compared to MT males. There was no difference in HRV between MT and control females.

Conflict of interest statement

Conflict of Interest Statement: The authors declare no conflict of interest and the study sponsors had no role in the study design, data collection, analysis, interpretation of the data, and the writing of this manuscript.

Copyright © 2013 Elsevier Ltd. All rights reserved.

Figures

Figure 1

LF:HF ratio during successive epochs of nursing care activity and sleep in female infants receiving massage therapy (MT) or Control. No significant differences were found over time or between groups.

Figure 2

LF:HF ratio during successive epochs of nursing care activity and sleep in male infants receiving massage therapy (MT) or Control. *LF:HF ratio significantly higher at baseline in the control group. **LF:HF ratio significantly decreased from baseline to the second caregiving epoch (cares 2) in Controls.