## 4 Discussion
### Main Findings  
Menstrual, weekly, and seasonal cycles exhibit similar patterns in elite athletes and the general population [3]. However, some distinctions between athletes with MC and those using HC were noted, and additional parameters were considered beyond mood [3]. The MC follows an infradian rhythm, with positive feelings peaking just after the menstruation phase (MC) or following the pill break (HC) and diminishing towards the end of the cycle. These findings align with results observed in the general population [3]. Some studies highlight the impact of hormonal fluctuations, particularly the rise in estrogen during the follicular phase, as a contributing factor to improved mood and overall wellness [21]. Elevated estrogen levels are associated with increased serotonin availability, a neurotransmitter linked to positive mood regulation [22]. Consequently, athletes with natural MC often experience heighten energy levels, motivation, and improved cognitive function during the early phases of their MC [23; 24]. Conversely, the decline in estrogen and the simultaneous drop in progesterone levels at the end of the cycle can contribute to lower mood scores and a decrease in overall wellness [22; 25]. This aligns with the observed negative mood symptoms during the end of the MC in this study or with what is commonly observed in the general population [3]. Such cycle variations have been shown in studies involving rowers [5], rugby players [23], and soccer players [24]. For athletes using HC, the pattern slightly differs, possibly due to diminished hormonal fluctuations caused by the downregulation of the gonadotropic axis. Positive feelings are often reported following the break of the hormonal pills, mimicking the rise in estrogen seen in the MC. However, during the pill's inactive phase, when exogeneous hormonal levels decline, athletes may experience a dip in mood and energy levels, similar to the hormonal fluctuations in the late stages of the MC. It also explains the prevalence of symptoms observed during the menstruation phase and the pill break [15; 26], similarly observed in the general population [27]. The magnitude of hormonal variation with HC use is lower compared to a natural cycle, leading to reduced hormonal fluctuations, which may contribute to more stable levels of mood, motivation, and energy. This stability can be perceived as beneficial for athletes who need to maintain consistent levels of performance. Current evidence is insufficient to determine whether HC use has a positive, neutral, or negative impact on performance over the long term. Additionally, this stability may present disadvantages, such as limiting potential positive physiological effects associated with the estrogen rise, like enhanced physical capacity to endure intense training [16; 28]. No differences related to menstrual symptoms were observed over the week, showing that athletes were able to distinguish symptoms related to their menstrual cycles from any sports-related pain. The potential influence of seasons, with symptom frequencies higher in summer and lower in autumn and winter, needs to be interpreted with caution due to the off-season. A majority of the athletes were not monitored during summer because they interrupted their training. It is therefore possible that only those with the most painful symptoms reported them. While the general population shows better wellness indicators on Saturdays followed by a decline on Sundays [3], athletes in our study exhibit consistent mood levels across weekend days and a re-increase in fitness levels on Tuesday and Wednesday. These variations can be attributed to the specificities of our athlete's schedule where Sunday is the usual competition day, boosting greater motivation and improved mood, whereas Monday is a rest day following the competitive weekend.