Research results suggest changes of physiological parameters such as heart rate, respiration, skin conductance response, sleep duration, sleep quality and skin perfusion during the menstrual cycle. Latest fitness trackers allow to conveniently and non-invasively record these parameters. The present study aims to evaluate whether there is a correlation between physiological parameters and the menstrual cycle i.e. ovulation as measured by a urine ovulation test and the onset of menses. To collect data women will wear two smartwatches and a smartshirt at night. All three devices are CE-approved for sports and fitness.

Inclusion Criteria:

• Healthy, non-pregnant women aged 20-40 years (healthy volunteers)
• Regular cycling (28 days +/- 2)
• Non-hormonal contraception methods used
• German-speaking
• Written informed consent to participate in the study

Exclusion Criteria:

• Any health-related issues that may affect menstrual cycle
• Any consumption of medication or other substances that may affect the menstrual cycle or any of the physiological parameters investigated
• Frequent travel between time zones
• Sleeping disorders

The monitoring of menstrual cycles requires female participants.

A maximum of 50 healthy, 20-40 years old, non-pregnant women will be included in the study.