Cardiovascular responses during the menopausal hot flush.

Circulatory responses during spontaneous and stress induced menopausal flushes were measured by a plethysmographic technique. With the onset of symptoms there was an immediate and marked increase in hand blood flow which was sustained over three to four minutes and then fell to control levels over a further three minutes. Forearm and calf flow increased simultaneously through to a lesser extent and regained control levels within four-and-a-half minutes from the onset of symptoms. Mean pulse rate also increased during the flush but fell to control values at a time when limb flow was still elevated. There was no significant change in blood pressure during or after the flush. The peripheral circulatory exchanges are attributed to altered autonomic activity and may in part reflect a disturbance of thermoregulatory control in the menopause of which the flush is but one manifestation.