Differences in autonomic neural activity during exercise between the second and third trimesters of pregnancy

Akemi Nakagaki, Takayuki Inami, Tetsuji Minoura, Reizo Baba, Satoshi Iwase, Motohiko Sato

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)


Aim: To test the hypothesis that autonomic neural activity in pregnant women during exercise varies according to gestational age. Methods: This cross-sectional study involved 20 healthy women in their second (n = 13) or third (n = 7) trimester of pregnancy. Incremental cardiopulmonary exercise testing was performed with an electromagnetic cycle ergometer. Heart rate variability was analyzed by frequency analysis software. Results: The low-frequency to high-frequency (LF/HF) ratio, an indicator of the sympathetic nervous system, was significantly higher in third trimester than in second trimester subjects (P < 0.05) at 1, 2, and 3 min of incremental exercise testing. In contrast, the HF/total power ratio, an indicator of rapidly acting parasympathetic activity, was significantly higher in second trimester than in third trimester subjects (P < 0.05) at 2 and 3 min. In addition, a negative correlation was found between gestational age and the ‘accumulation half-time’ of the LH/HF ratio, the time point at which the sum of the LF/HF ratio reached 50% of that accumulated in the total 6 min of exercise testing (r = −0.49, P = 0.028). Conclusions: The autonomic response to exercise in pregnant women differs between the second and third trimesters. These differences should be considered when prescribing exercise to pregnant women.

Original languageEnglish
Pages (from-to)951-959
Number of pages9
JournalJournal of Obstetrics and Gynaecology Research
Issue number8
Publication statusPublished - 2016 Aug 1
Externally publishedYes


  • autonomic neural activity
  • exercise
  • pregnant women
  • second trimester
  • third trimester

ASJC Scopus subject areas

  • Obstetrics and Gynaecology


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