Sleep and Your Menstrual Cycle: Why Rest Changes Through the Month

If you sleep beautifully for two weeks and toss for the next two, your hormones are likely co-authors of the pattern.

The sleep-cycle connection

Progesterone in the luteal phase has sedative-like properties early on but is linked to fragmented sleep and higher body temperature overnight — one reason the second half of the cycle feels heavier. Just before menstruation, the hormone drop can disrupt sleep further.

Signs worth watching

• Sleep disruption that clusters in the same phase every cycle
• Nighttime temperature elevations
• HRV suppression overnight during high-stress weeks

What helps

Consistent wake times, cooler bedrooms, iron status checked when fatigue is heavy, and — above all — knowing which phase you're in, so you stop blaming your willpower for your physiology.

Femora collects temperature, heart rate and HRV overnight by design, because the night is when your body tells its clearest story.