Figure 5.

The relationship between the combination of lunar phase (light, dark, neutral periods) in the two most recent menstruation onsets and subjective sleep quality among participants with mean menstrual cycle = 29.5 ± 1 days (A) and those with mean menstrual cycle greater than or less than 29.5 ± 1 days (B). There was no statistically significant relationship between lunar phase and sleep quality among participants with a menstrual cycle of 29.5 ± 1 days (A). In contrast, there was a significant relationship between lunar phase and sleep quality, with a gradual change in lunar phase at the onset of menstrual cycle due to longer or shorter mean menstrual cycle length (B).