Menstrual cycle phase does not affect sympathetic neural activity in women with postural orthostatic tachycardia syndrome.

Key Points: Women with the postural orthostatic tachycardia syndrome (POTS) report fluctuations in orthostatic tolerance throughout the menstrual cycle. The mechanism(s) underlying blood pressure control across the menstrual cycle in women with POTS are unknown. The findings of the present study indicate that the menstrual cycle does not affect muscle sympathetic nerve activity but modulates blood pressure and vasoconstriction in POTS women during orthostatic stress.

Relationship between sympathetic baroreflex sensitivity and arterial stiffness in elderly men and women.

Previous human studies have shown that large-artery stiffness contributes to an age-related decrease in cardiovagal baroreflex sensitivity. Whether this is also true with sympathetic baroreflex sensitivity is unknown. We tested the hypothesis that sympathetic baroreflex sensitivity is associated with the stiffness of baroreceptor segments (the carotid artery and the aorta) in elderly individuals and that sex affects this relationship.

Exercise training versus propranolol in the treatment of the postural orthostatic tachycardia syndrome.

We have found recently that exercise training is effective in the treatment of the postural orthostatic tachycardia syndrome (POTS). Whether this nondrug treatment is superior to "standard" drug therapies, such as β-blockade, is unknown. We tested the hypothesis that exercise training but not β-blockade treatment improves symptoms, hemodynamics, and renal-adrenal responses in POTS patients.

Sex differences in the modulation of vasomotor sympathetic outflow during static handgrip exercise in healthy young humans.

Sex differences in sympathetic neural control during static exercise in humans are few and the findings are inconsistent. We hypothesized women would have an attenuated vasomotor sympathetic response to static exercise, which would be further reduced during the high sex hormone [midluteal (ML)] vs. the low hormone phase [early follicular (EF)].

Effects of exercise training on arterial-cardiac baroreflex function in POTS.

Purpose: Postural orthostatic tachycardia syndrome (POTS) is characterized by excessive tachycardia in the upright position. To test the hypothesis that patients with POTS have impaired arterial-cardiac baroreflex function, while exercise training normalizes the baroreflex function in these patients.

Methods: Seventeen POTS patients aged 27 ± 9 (mean ± SD) years underwent an exercise training program for 3 months.