104. How Light Shapes Hormones with Sarah Kleiner

Perimenopause can feel like your body is sending mixed signals. Appetite shifts. Sleep changes. Stress tolerance shrinks. And when labs come back “normal,” it can leave you feeling unheard in your own experience. In this episode, I sit down with Sarah Kleiner to explore circadian rhythm as a foundational regulator of women’s hormones. We unpack leptin as a master safety signal that influences thyroid function, reproductive hormones, metabolism, and appetite. We also discuss how artificial light, screens, chronic stress, and restrictive dieting can blunt this signaling, especially in midlife when resilience narrows. This conversation reframes hormone imbalance through the lens of rhythm and nervous system regulation rather than quick fixes. You’ll walk away with simple, practical ways to begin restoring amplitude to your day, starting with light, timing, and nourishment. Sarah Kleiner is the founder of Sarah Kleiner Wellness and the creator of My Circadian App.  What's Discussed: (00:00) Midlife as recalibration and why hormones reflect circadian rhythm and safety (07:30) Leptin as a master signal and how it informs thyroid, metabolism, and fertility (15:00) Cortisol, melatonin, and the hormonal cascade shaped by morning and evening light (23:00) How artificial light, screens, and late eating disrupt hormone signaling (31:00) Restrictive dieting, fasting, and why low leptin states keep women stuck (39:00) Nervous system regulation and how chronic stress blunts metabolic communication (47:00) Fertility, perimenopause, and why resilience narrows in midlife (55:00) Practical circadian shifts for busy women and families (1:03:00) Rhythm as root healing and returning to biological coherence Thank You to Our Sponsors: Ancient + Brave: Visit ancientandbrave.com and use code MONA for $10 off any order. IM8: Try IM8 for 30 days as part of your holistic wellness practice. Your body deserves this level of comprehensive support. Visit https://im8health.com/  Timeline: Get 35% off your first month at Timeline.com/MONA35. Learn more about Mona Sharma: Download Your FREE Guide - 12 Wellness Tips to Unlock Your Best Health Now: Ready to reclaim your vitality? Download Mona’s 12 Wellness Tips and take actionable steps to transform your health, energy, and mindset. Get started now at https://monasharma.com/12tips.  Visit Mona's website: https://monasharma.com – Unlock powerful tools and wisdom rooted in wellness to elevate your health, energy, and clarity. Mona blends ancient healing practices with modern science to help you achieve lasting transformation. Follow Mona on Instagram: Stay connected with Mona for daily inspiration, holistic health tips, and personal growth. Join the conversation on Instagram at https://instagram.com/monasharma. Learn more about Sarah Kleiner: Website: https://www.sarahkleinerwellness.com/  Instagram: @sarahkleinerwellness