Cardiovascular autonomic responsiveness in postmenopausal women with and without hot flushes

Objectives: During menopausal transition autonomic balance is known to shift towards sympathetic dominance, but the role of vasomotor hot flushes in this phenomenon is not understood. We compared cardiovascular autonomic responsiveness between women with and without hot flushes.

Study design and main outcome measures: One hundred fifty recently postmenopausal healthy women with varying degree of hot flushes (none, mild, moderate, severe) underwent comprehensive cardiovascular autonomic nervous testing (controlled and deep breathing, active orthostatic test, Valsalva manoeuvre and handgrip test) assessing both sympathetic and parasympathetic activity. The responses of heart rate, heart rate variability and blood pressure in these tests were evaluated.

Results: Responses in heart rate showed differences between the study groups only in the Valsalva manoeuvre where the tachycardia ratio in all symptomatic women was lower (p=0.041) than in women without hot flushes. Neither change in the heart rate variability analyses nor the blood pressure responses were affected by hot flush status. However, there was a non-significantly higher maximum systolic (140 (112-182)mmHg vs. 135 (102-208)mmHg) and diastolic blood pressure (94 (72-112)mmHg vs. 90 (66-122)mmHg) following the handgrip test in women without hot flushes vs. all the symptomatic women.

Conclusions: Menopausal hot flushes seem to be associated with a possibly increased sympathetic preponderance without an effect on parasympathetic activity in cardiovascular autonomic responses. This may imply a potentially negative impact on cardiovascular health in women experiencing hot flushes.