#319 - What Has Whoop Actually Learned from Studying 3 Million Users? | Dr. Greg Grosicki & Mike Haney

Continuous health data gives researchers something they have rarely had before: the ability to follow the same person, in the real world, across thousands of measurements and long periods of time. That can reveal patterns that disappear when we rely on a single clinic visit, a short experiment, or an average drawn across very different people.

Mike Haney talks with WHOOP researcher Dr. Greg Grosicki about what scientists are learning from these massive longitudinal datasets, why your own baseline can sometimes matter more than a population reference range, and what continuous measurement could mean as wearables begin capturing far more than heart rate and sleep.

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What We Cover:

• Why HRV is often more useful compared with your own history than with someone else’s
• What millions of nights reveal about alcohol, recovery, and next-day behavior
• How wearable signals can begin changing before you feel sick
• What huge observational datasets can and cannot tell us about cause and effect
• Why measuring people continuously may change how we define “normal”

🎙️ About the Guest:

Dr. Greg Grosicki is a research scientist at WHOOP and an exercise physiologist whose work uses large-scale longitudinal wearable data to study cardiovascular physiology, sleep, activity, recovery, and health behavior.

📍What Dr. Greg Grosicki & Mike Haney discussed:

• 00:04 - Compare your HRV with your own history, not someone else's
• 04:20 - Forty people in a lab miss the other 23 hours
• 10:51 - Heart rate, movement, and sleep from one band worn all day
• 13:02 - An 80-year-old can outscore a Tour rider. That is the wrong comparison
• 22:45 - One drink, several drinks, and a last drink before 5 p.m. do not land the same
• 27:28 - Even one drink you do not feel raises heart rate and shortens sleep
• 32:32 - The same drinks hit women harder, and younger adults harder than older ones
• 35:48 - More exercise before drinking made the night worse, not better
• 42:31 - HRV can dip two or three days before you report being sick
• 44:52 - More wear tracks with better numbers. That does not prove the band caused them
• 53:46 - The sharper test is your high-wear weeks against your own low-wear weeks
• 55:32 - HRV can run from about 5 to 400. Stability tells you more than the average
• 1:11:24 - A million nights can hide the one night that is yours
• 1:15:39 - Blood pressure is the measurement he wants on the wrist next

🔗 Helpful Links:

Real-world effects of alcohol on heart rate, sleep, and physical activity by age and sex — PLOS Digital Health (2026)

More than 5 million nights of wearable data on alcohol’s effects. Read the study

Heart rate variability coefficient of variation during sleep as a digital biomarker — American Journal of Physiology (2026)

How HRV stability varies with behavior, age, and sex. Read the study

Wearing WHOOP More Frequently Is Associated with Better Biometrics and Healthier Sleep and Activity Patterns — Sensors (2025)

Longitudinal analysis of nearly one million days and nights. Read the study

Alcohol Use Trajectories During the First 72 Weeks of WHOOP Wearable Platform Membership — JMIR mHealth and uHealth (2026)

Alcohol use patterns across 30,000 members over time. Read the study

Watch the conversation: https://youtu.be/Metbt5cMxX4

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👋 Who we are:

Levels helps you understand your metabolic health with personalized data, expert guidance, and tools that connect your daily choices to measurable changes in your body. Our goal is to help you make better decisions about food, exercise, sleep, and long-term health.

Look for new shows every month on A Whole New Level, where we have in-depth conversations with thought leaders about metabolic health.