A new study published in NPJ Digital Medicine suggests that women who regularly sleep too little or have inconsistent sleep schedules may be more likely to experience irregular menstrual cycles.

Researchers analyzed data from 2,596 women using WHOOP wearable devices, examining more than 42,000 menstrual cycles and over 1.29 million days of physiological and sleep data. The findings showed that shorter sleep duration and irregular sleep patterns were strongly associated with greater variability in cycle length.

According to the researchers, women sleeping fewer than 7.3 hours per night tended to have less stable menstrual cycles. The study also found that fluctuations in physiological markers such as resting heart rate, respiratory rate, and heart rate variability changed noticeably throughout the menstrual cycle.

The average cycle length among participants was 28.4 days, with cycle duration generally decreasing with age. Scientists also observed that physiological rhythms became less pronounced as women got older.

The authors noted that although overall population trends were consistent, individual women showed significant differences in biometric patterns from cycle to cycle. They emphasized that personalized approaches may be important for understanding menstrual health.

The researchers concluded that maintaining regular and sufficient sleep could play an important role in supporting menstrual cycle stability and overall well-being. They added that future studies should explore whether improving sleep habits can help reduce menstrual irregularities.