Found this fascinating... "Resting sympathetic outflow is greater during the luteal phase – when both oestrogens and progesterone are elevated – compared with the early follicular phase of the menstrual cycle – when both oestrogens and progesterone are low (Minson et al. 2000a; Carter et al. 2009b; Fu et al. 2009). During an orthostatic challenge, total MSNA (which takes into account the area under the MSNA burst) is also greater in the mid-luteal versus early follicular phase (Carter et al. 200