A new study published in the European Journal of Sport Science explored the effects of estrogen and progesterone fluctuations across menstrual cycle, on fluid and electrolyte balance. This review aimed to provide information for the exercising female, as well as for researchers working in this field.

It was described how estrogen and progesterone have independent and integrated roles in the regulation of fluid-electrolyte balance. Estrogen can influence the osmotic threshold for arginine-vasopressin release while progesterone can influence aldosterone production. However, these actions do not appear to influence fluid retention, plasma volume changes at rest and during exercise or electrolyte losses. Whereas, the large inter-individual variations in hormonal fluctuations throughout the menstrual cycle may signify thatsome individuals with high fluctuations could experience disturbances in their fluid-electrolyte balance. 

During phases of estrogen dominance (e.g. late-follicular phase) heat dissipation is promoted, while progesterone dominance (e.g. mid-luteal phase) promotes heat conservation, with overall higher basal body temperature. These responses do not consistently lead to any change in observed sweat rates, heat-stress or dehydration during exercise. The literature does not support any difference in fluid retention during post-exercise rehydration periods conducted at different menstrual cycle phases. These mean responses largely reveal no effects on fluid-electrolyte balance.

Source: European Journal of Sport Science.2021 Jun 17;1-12. doi: 10.1080/17461391.2021.1939428.