In this episode of unPAUSED, Dr. Mary Claire Haver sits down with Dr. Kristen Holmes, Vice President of Performance Science at Whoop and author of the new book Aligned, to unpack why sleep and circadian rhythm matter as much as hormones when it comes to the symptoms women feel in perimenopause and menopause.
Dr. Holmes explains the concept of circadian amplitude, the contrast between activity and rest, light and dark, and fed and fasted states that keeps every system in the body running on time, and why women with lower amplitude tend to report more frequent and more severe symptoms. She walks through why morning light exposure is one of the most powerful and underused tools available, how getting outside within the first part of the day sets the timing for melatonin release that night, and why a window is not a substitute for actual daylight.
The conversation moves into meal timing, including why the body is more insulin sensitive earlier in the day and how consolidating calories into a shorter window can support better sleep and metabolic health. Dr. Holmes also covers where movement fits, including the specific role of zone two training in recovery, why late night intense exercise can work against sleep, and how alcohol affects women differently than men at the same dose.
Dr. Holmes and Dr. Haver also dig into what actually drives a 3am wake up, tracing it back to progesterone, GABA signaling, and the loss of hormonal stability that comes with perimenopause, and why sedatives can mask the problem without improving sleep architecture. The conversation ends with a look at the data connecting circadian misalignment to shift work, mental health, and long term health risk, and what a woman can start doing tonight to build back that rhythm.
Guest links:
-
Dr. Kristen Holmes (Instagram)
-
Dr. Kristen Holmes, PhD (LinkedIn)
- The Line with Dr. Kristen Holmes (Apple Podcasts)
Books:
-
“Aligned: The Data-driven Guide to Performance, Recovery, and Human Potential,” by Kristen Holmes
-
“The New Perimenopause,” by Dr. Mary Claire Haver
- “The New Menopause," by Dr. Mary Claire Haver
Articles:
-
Sleep regularity is a stronger predictor of mortality risk than sleep duration: A prospective cohort study (Sleep)
-
The menstrual cycle through the lens of a wearable device: insights into physiology, sleep, and cycle variability (npj Digital Medicine)
-
Real-world effects of alcohol on heart rate, sleep, and physical activity by age and sex (PLOS Digital Health)
-
Alcohol Use Trajectories During the First 72 Weeks of WHOOP Wearable Platform Membership: Observational Cohort Study (JMIR)
-
Timing of food intake predicts weight loss effectiveness (International Journal of Obesity)
-
Dose-response relationship between evening exercise and sleep (Nature Communications)
-
Pre-sleep protein supplementation after an acute bout of evening resistance exercise does not improve next day performance or recovery in resistance trained men (Applied Physiology, Nutrition, and Metabolism)
-
Four core circadian behaviors that improve cardiorespiratory fitness through consistent sleep (Sleep)
-
Brief structured respiration practices enhance mood and reduce physiological arousal (Cell Reports Magazine)
-
What Happens on Call Doesn't Stay on Call. The Effects of In-house Call on Acute Care Surgeons' Sleep and Burnout: Results of the Surgeon Performance (SuPer) Trial (Annals of Surgery)
-
Cardiac responses to daily threats and challenges during wakefulness and sleep (Emotion)
-
Enhancing circadian rhythms—the circadian MEGA bundle as novel approach to treat critical illness (ATM)
-
Circadian misalignment increases mood vulnerability in simulated shift work (Scientific Reports)
-
Association between accelerometer-measured amplitude of rest–activity rhythm and future health risk: a prospective cohort study of the UK Biobank (The Lancet)
-
Sleep Disturbance and Perimenopause: A Narrative Review (Journal of Clinical Medicine)
-
Metabolomics Pilot Study Identifies Desynchronization of 24-H Rhythms and Distinct Intra-patient Variability Patterns in Critical Illness: A Preliminary Report (Frontiers in Neurology)
- Social Jetlag and Related Risks for Human Health: A Timely Review (Nutrients)
Other Resources:
-
Wu Tsai Human Performance Alliance will explore peak performance to help all people thrive throughout life (Stanford Report)
-
Scott Delp - Director, Wu Tsai Human Performance Alliance at Stanford
-
Experts see a wide data gap in women’s sports science. This WNBA team owner wants to fix it (Associated Press)
-
New WHOOP Studies Show Even Moderate Alcohol Disrupts Sleep and Recovery - and Members Reduce Drinking Over Time
- How stress affects sleep, cognitive performance, and recovery