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Elevated Cardiac Vagal Tone in Hypoestrogenic Active Premenopausal Women With Functional Hypothalamic Amenorrhea

The study investigates heart rate and autonomic modulation in exercise-trained women with functional hypothalamic amenorrhea (ExFHA) compared to eumenorrheic women. Findings indicate that ExFHA women exhibit elevated cardiac vagal tone, characterized by lower heart rate and blood pressure, and higher heart rate variability at rest and during stress. This suggests altered autonomic regulation, potentially influenced by lower central angiotensin II levels.

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19 views2 pages

Elevated Cardiac Vagal Tone in Hypoestrogenic Active Premenopausal Women With Functional Hypothalamic Amenorrhea

The study investigates heart rate and autonomic modulation in exercise-trained women with functional hypothalamic amenorrhea (ExFHA) compared to eumenorrheic women. Findings indicate that ExFHA women exhibit elevated cardiac vagal tone, characterized by lower heart rate and blood pressure, and higher heart rate variability at rest and during stress. This suggests altered autonomic regulation, potentially influenced by lower central angiotensin II levels.

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jobs.sevenfold142
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View metadata, citation and similar papers at core.ac.

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provided by Loughborough University Institutional Repository

Elevated Cardiac Vagal Tone in Hypoestrogenic Active Premenopausal Women with

Functional Hypothalamic Amenorrhea

Emma O’Donnell1, Jack M Goodman1,2, Beverly L Morris3, John S Floras2,3,

and Paula J Harvey4

1
Cardiovascular Research Laboratory, Department of Exercise Sciences, University of Toronto,

Toronto, Ontario, Canada, and Division of Cardiology at the 2Mount Sinai Hospital, 3Toronto

General Hospital, and 4Women’s College Hospital, University of Toronto, Ontario, Canada.

Compared with eumenorrheic women, exercise-trained women with functional hypothalamic

amenorrhea (ExFHA) have a low heart rate (HR), absent reflex activation of their renin-

angiotensin-system, and augmentation of the normal increase in muscle sympathetic nerve

burst incidence during orthostatic stress, suggesting concurrently altered autonomic HR

modulation. To test this hypothesis, three age-matched (pooled mean, 24±1 years;

mean±SEM) groups of women were studied: ExFHA (n=11), exercise-trained and eumenorrheic

(ExOv; n=17), and sedentary and eumenorrheic (SedOv; n=17). Blood pressure (BP), HR, and

HR variability (HRV) in the frequency domain were measured at supine rest and during

simulated orthostatic stress induced by graded lower body negative pressure (LBNP; -10, -20,

and -40mmHg). Very low (VLF), low (LF) and high (HF) frequency power spectra (ms2) were

determined, and due to skewness, were log10 transformed. LF/HF ratio and Total power

(VLF+LF+HF) were calculated. At baseline, HR and systolic BP were lower (p<0.05), and HF

and Total power higher (p<0.05) in ExFHA than eumenorrheic women. In all groups, LBNP

decreased (p<0.05) systolic BP, HF and Total power, and increased (p<0.05) HR, and LF/HF

ratio. However, in ExFHA, HF and Total power remained higher (p<0.05), and HR, systolic BP
and LF/HF ratio lower (p<0.05) than in eumenorrheic women, in whom measures did not differ

(p>0.05). In conclusion, ExFHA women demonstrate augmented vagal HR modulation, whereas

sympathetic HR modulation is unchanged, both at rest and during orthostatic stress. Less

central angiotensin II may play a role.

Abstract Sponsor: Dr. John S Floras

Sponsor email: jfloras@mtsinai.on.ca

Sponsor telephone number: 416-586-8704

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