During the follicular phase, estrogen and follicle-stimulating hormone begin to rise, prompting the ovaries to release eggs and thickening the uterus in preparation for the egg's arrival, Dr. Mahalingaiah said. According to proponents of cycle synchronization, during this stage the body is ready for stress and can recover more quickly. Juliana Antero, a researcher at the French Institute of Sport, is leading the French Ministry of Sport's Empowerher program, which tailors the training schedules of professional athletes to their cycles in the run-up to the 2024 Olympics. Antero said, anecdotally, that she observed a “burst of energy” in athletes during this phase. This means athletes can “better handle high-intensity training loads, run faster, and become more powerful.” As part of a personalized training plan, the highest intensity activities are scheduled during the follicular phase.
The release of the egg (ovulation) is followed by the luteal phase. The luteal phase is characterized by high levels of progesterone, a hormone responsible for maintaining a stable environment in the uterus for fertilized eggs. The luteal phase can be associated with symptoms of premenstrual syndrome, such as bloating and low energy. Stacey Sims, a sports nutrition physiologist and former athlete who studies menstrual cycles and performance in professional athletes, says that during this period, the body has more recovery time between workouts and is better suited for low-intensity activity. He said that there is a possibility that
But Dr. Clancy, who is also the author of “The Menstrual Cycle: The True Story of Menstruation,'' said cycles rarely follow the typical peak-and-trough pattern. “If you look at the hormonal cycles of hundreds of people, you won't find a textbook person.” For example, some women skip ovulation for several cycles or have multiple estrogen surges. . And it remains unclear whether cycle synchronization makes sense for women using hormonal contraception.
Scientific and anecdotal evidence showing fluctuations in performance and energy across the menstrual cycle also does not prove that synchronizing your workouts to your menstrual cycle will optimize your fitness. “From a medical standpoint, there's not enough evidence,” said Dr. Ashima Ahmad, a reproductive endocrinologist and chief medical officer of a fertility benefits provider called Carrot Fertility. “That's not something I would recommend to my patients.”
Antero and Scott acknowledged the lack of research on this method, which they said is a sign of growing disparities in women's health research. Antero said one of his main objectives for the EmpowerHer program is to fill that void. She plans to present the results of her training program after the Olympics.
