Fit For Science

Data scientists Rob and Stephan discuss Apple's latest sleep algorithm improvements, the evolving landscape of wearable subscriptions, and three reasons for personal (health) tracking.📝SummaryIn this episode, the hosts examine the rapid iteration cycles of health technology, starting with Apple’s recent algorithmic improvements to sleep stage detection. They explore the "subscriptionification" of the wearable industry, comparing business models from Whoop, Oura, and Eight Sleep while debating the value of AI-driven health coaching and gamification metrics like "biological age". The discussion transitions into nutritional tracking, covering the medical origin of continuous glucose monitors (CGMs) and the practical challenges of picture-based food logging. Finally, they dive into three reasons behind self-quantification, highlighting for example how the Hawthorne effect, where the act of observation itself alters behavior, can be a powerful tool for behavior change.⏳Chapters00:00:00 Apple Sleep Algorithm: Improved deep sleep and awake detection 00:09:00 Continuous Sleep: Moving beyond 30-second epoch sleep stages 00:13:20 Data Repositories: The lack of centralized sleep data compared to genomics 00:17:20 Subscription Models: The industry shift from ownership to service licenses 00:35:00 AI Coaching: The utility and hype of AI advisors in wearables 00:44:00 Eight Sleep: Thermal regulation, bed tracking, and high-tier costs 01:13:50 CGM Deep Dive: Continuous glucose monitoring and individual responses 01:29:30 Nutrition Tracking: From barcodes to picture-based food logging 01:35:20 The Hawthorne Effect: Using observation as a tool for behavior change 01:42:00 Management Philosophy: Drucker and Kelvin on the necessity of measurement01:47:40 Technological Optimism: Staying healthy to witness the future📚ResourcesApple sleep staging paper with updated appendix: https://www.apple.com/health/pdf/Estimating_Sleep_Stages_from_Apple_Watch_Oct_2025.pdf The Quantified Scientist - Can Wearables Predict How You Feel?: https://youtu.be/iwZrtb6tlUo Apple Health uses SDNN (Standard Deviation of Normal-to-Normal intervals) as its metric for Heart Rate Variability, while others (such as Oura, Garmin, and Fitbit) use RMSSD.Eight Sleep: https://www.eightsleep.com/ Dexcom G7 & Stelo: https://www.dexcom.com/ FreeStyle Libre by Abbott: https://www.freestyle.abbott/ Levels Health App: https://framer.levels.com/ A glucose spike is a rapid rise in blood sugar, defined generally as above 140 mg/dL.Nature Medicine paper on individual variations in glycemic responses: https://www.nature.com/articles/s41591-025-03719-2Clarification: Not Ultrahuman (https://www.ultrahuman.com/) but Supersapiens (https://www.supersapiens.com/) use CGMs for optimal metabolic fueling/efficiency.rTracker app by Robert Miller: https://apps.apple.com/us/app/rtracker-track-it-your-way/id486541371Star Trek Qs (immortal species): https://en.wikipedia.org/wiki/Q_(Star_Trek) Isaac Asimov's Foundation as TV series: https://en.wikipedia.org/wiki/Foundation_(TV_series) Three Body Problem as TV series: https://en.wikipedia.org/wiki/3_Body_Problem_(TV_series) 🎙️AboutFit For Science is a deep-dive podcast hosted by two biological data scientists, Rob and Stephan, exploring the intersection of research, health tech, and data-driven lifestyle design. Learn more: https://www.fitforscience.com/ Subscribe on your favorite platformsYouTube: https://www.youtube.com/@FitForScience Spotify: https://open.spotify.com/show/56TjUxuMsPETb0kGEJ7nwf Apple Podcasts: https://podcasts.apple.com/us/podcast/fit-for-science/id1863479802Amazon Music: https://music.amazon.de/podcasts/c3e54ee7-4a2c-442e-a59f-553fbfb02b11/fit-for-science ⚠️Disclaimer: This podcast represents our own opinions and is for informational purposes only. It does not constitute medical or financial advice or a professional relationship.

Rob and Stephan discuss the efficacy of blood pressure wearables, morning activation protocols like light therapy, and the use of nicotine as a cognitive stimulant.📝SummaryIn this episode, biological data scientists Rob and Stephan examine the evolution of wearable technology, focusing on Garmin’s Firstbeat sleep staging and the current limitations of wrist-based blood pressure monitoring. They contrast Apple’s cautious notification-based approach to hypertension with the calibration-heavy methods of competitors, while discussing why continuous monitoring might be superior to traditional resting spot checks. The conversation shifts to personal morning "activation" rituals, featuring a deep dive into light therapy for circadian rhythm alignment and the controversy surrounding cyclic hyperventilation. Finally, they explore the potential cognitive benefits and physiological risks of nicotine supplementation, alongside Stephan’s "Minimal Effective Dosage" daily strength exercise for long-term health maintenance.⏳Chapters00:00:00 Wearable Evolution: Firstbeat Sleep Staging and Incremental Innovation00:09:12 Scientific Standards: Peer Review vs. Corporate White Papers 00:13:12 Blood Pressure: Cardiovascular Risk and Genetic Predisposition 00:15:07 Gold Standards: Manual Cuffs vs. Wrist-Based Sensors 00:21:18 Apple's Approach: Hypertension Notifications and Data Integrity 00:30:00 Future Research: Continuous Monitoring vs. Resting Spot Checks 00:37:39 Morning Activation: Overcoming Sleep Inertia with Light Therapy 00:42:21 Morning Routines: Caffeine, Cold Showers, and Cognitive Performance 00:50:49 Coffee and Cholesterol: The Impact of Paper Filters on Serum LDL-C00:52:37 Beyond Wim Hof: Cyclic Hyperventilation and Acupuncture Mats 01:00:33 Nicotine as a Nootropic: Misconceptions, Risks, and Half-Life 01:13:39 Minimal Effective Dosage: Non-Negotiable Daily Exercise Habits 📚Resources2019 Firstbeat (now Garmin) sleep analysis paper: https://assets.firstbeat.com/firstbeat/uploads/2019/11/Firstbeat-Sleep-Solution_white-paper_short.pdf ASCVD: Atherosclerotic Cardiovascular DiseaseMACE: Major Adverse Cardiovascular EventsBlood pressure (BP) & ASCVD risk: https://jamanetwork.com/journals/jamacardiology/fullarticle/2766469 Blood pressure at night: 10%–20% decreaseSleep inertia: https://en.wikipedia.org/wiki/Sleep_inertiaLuminette glasses: https://myluminette.com/ Light as major zeitgeber: https://pubmed.ncbi.nlm.nih.gov/19708721/ Stephan's morning: morning.polytechnist.me Use paper filters for coffee to reduce LDL-C: https://www.ahajournals.org/doi/10.1161/01.ATV.11.3.586 Cyclic hyperventilation (Bhastrika Pranayama) for sympathetic activation: https://pubmed.ncbi.nlm.nih.gov/24799686/ Stephan's nicotine page: https://stephanreichl.notion.site/Nicotine-2d0301f67e4c80faa34ec6c032a35bd5Stephan's “minimal effective dose” strength training: https://stephanreichl.notion.site/MED-Resistance-Training-7ecf3c212aa248838903dbfbfcb7230eHot Baths as exercise: https://journals.physiology.org/doi/epdf/10.1152/ajpregu.00012.2025🎙️AboutFit For Science is a deep-dive podcast hosted by two biological data scientists, Rob and Stephan, exploring the intersection of research, health tech, and data-driven lifestyle design. The hosts provide evidence-based systems, layered with practical "N=2" personal experimentation, to cut through the noise in the health and fitness industry.Learn more: https://www.fitforscience.com/ Subscribe on your favorite platformsYouTube: https://www.youtube.com/@FitForScience Spotify: https://open.spotify.com/show/56TjUxuMsPETb0kGEJ7nwf Apple Podcasts: https://podcasts.apple.com/us/podcast/fit-for-science/id1863479802Amazon Music: https://music.amazon.de/podcasts/c3e54ee7-4a2c-442e-a59f-553fbfb02b11/fit-for-science ⚠️Disclaimer: This podcast represents our own opinions and is for informational purposes only. It does not constitute medical or financial advice or a professional relationship.

Rob and Stephan dive into the "deep sleep problem" of the Apple Watch, share their personal motivations for long-term self-quantification, and provide a science-heavy look at why creatine is one of the most underappreciated supplements in medicine.📝SummaryIn this episode, Rob addresses the controversy surrounding Apple Watch sleep staging based on a recent study comparing wearables to polysomnography, explaining why the device often underestimates deep sleep stages while remaining a top-tier consumer tool. The hosts explore the "why" behind their data-driven lifestyles, with Rob detailing his unique multi-year deep-phenotyping research and Stephan describing the psychological benefits of leveraging the Hawthorne effect for behavioral change. Finally, they provide a comprehensive breakdown of creatine supplementation, addressing medical misconceptions about kidney health, while also highlighting emerging research on creatine’s cognitive benefits.⏳Chapters00:02:00 The Sleep Study: Comparing Apple Watch to the Gold Standard00:12:41 Staging Accuracy: Pattern Recognition and Consistency Preferences00:17:15 Battery vs. Precision: Why Apple Limits Sensor Input00:24:20 Evolving Models: Firstbeat, Garmin, and Machine Learning on the Edge00:29:48 Why We Track: Rob’s Multi-Year Deep Phenotyping Research00:38:29 Finding the Niche: From Science Communication to YouTube00:44:17 Daily Routines: When and How to Check Your Data00:50:52 Healthy Limits: Preventing Tracking-Induced Anxiety00:56:48 Creatine and Kidney Health: Addressing Doctor Concerns00:57:50 Informed Discussions: How to Present Data to Medical Professionals01:08:18 Cellular Energy: Creatine’s Role in ATP Production01:13:04 Brain Health: Creatine for Sleep Deprivation and Neuroprotection01:19:32 Personal Risk Analysis: Hair Loss, Finasteride, and Trade-offs01:28:03 Soleus Muscle Correction and Smartwatch Histories📚ResourcesRob's sleep study preprint: https://osf.io/preprints/psyarxiv/27wun_v1 Apple sleep staging paper: https://www.apple.com/health/pdf/Estimating_Sleep_Stages_from_Apple_Watch_Oct_2025.pdf Quantization in AI: https://arxiv.org/abs/2106.08295 Oura technical support confirmed that Oura's sleep staging is processed offline by the Oura App, which runs the complete sleep staging pipeline using the physiological signals shared by the ring, regardless of internet connection.Simon Sinek's Start with Why: https://youtu.be/u4ZoJKF_VuA EXG Glossary: EEG (Electroencephalogram), EOG (Electrooculogram), ECG  (Electrocardiogram), EMG (Electromyogram)Supplement research database: https://examine.com Goodhart's Law: When a measure becomes a target, it ceases to be a good measure.Kidney physiology: https://youtu.be/l128tW1H5a8 Stephan's Creatine page: https://stephanreichl.notion.site/Creatine-117301f67e4c80fcbce8e9f489aad9c9 Hypertrophy (size) vs hyperplasia (numbers): https://pubmed.ncbi.nlm.nih.gov/5917072/ Fidgeting (NEAT) study: https://pubmed.ncbi.nlm.nih.gov/11101470/ 🎙️AboutFit For Science is a deep-dive podcast hosted by two biological data scientists, Rob and Stephan, exploring the intersection of research, health tech, and data-driven lifestyle design. The hosts provide evidence-based systems, layered with practical "N=2" personal experimentation, to cut through the noise in the health and fitness industry.Learn more: https://www.fitforscience.com/ Subscribe on your favorite platformsYouTube: https://www.youtube.com/@FitForScience Spotify: https://open.spotify.com/show/56TjUxuMsPETb0kGEJ7nwf Apple Podcasts: https://podcasts.apple.com/us/podcast/fit-for-science/id1863479802Amazon Music: https://music.amazon.de/podcasts/c3e54ee7-4a2c-442e-a59f-553fbfb02b11/fit-for-science ⚠️Disclaimer: This podcast represents our own opinions and is for informational purposes only. It does not constitute medical or financial advice or a professional relationship.

Biological data scientists Rob and Stephan discuss what to track and why, the psychological value of blue-light blocking glasses, and the multifaceted longevity benefits of "plogging".📝SummaryIn this episode, biological data scientists Rob and Stephan dive deep into the philosophy of self-quantification. They explore why tracking the "unobservable" state of sleep provides the highest return on investment and how the Hawthorne Effect can be used as a personal tool for behavior change. The discussion shifts to the science of blue light blocking glasses, debunking common marketing claims while acknowledging the power of psychological anchors in evening routines. Finally, the hosts introduce "Plogging", the Swedish habit of picking up litter while jogging, as a multifaceted longevity practice that combines movement, grip strength, and community purpose.⏳Chapters00:00:53 Wearables Philosophy: A discussion on what to track and why00:03:44 The SNAP Framework: Sleep, Nutrition, Activity, and Purpose00:06:18 Differentiating between Activity vs. Exercise00:09:41 Training Intensity: HIIT for speed and Zone 2 training for endurance00:15:30 Hardware Deep Dive: Comparing sports tracking versus sleep staging00:18:34 GPS Math and Measurement Noise: How devices calculate distance00:22:57 Market Leaders and Reviewer Ecosystems00:33:25 Blue Light Blocking Glasses: Examining the shifting evidence00:46:40 Psychological Anchors: How wearing red glasses signal to begin the evening routine00:49:56 Cold Exposure: Debunking metabolic and fat-loss claims00:55:38 Advanced Sleep Tech: EEG, polysomnography, and 30-second sleep staging epochs01:11:22 Tool Time - Plogging: Stephan introduces the ultimate longevity habit01:19:50 Systematic Culture: Comparing rule-following cultures in Austria vs the Netherlands01:28:40 Ig Nobel Science: Maternal garlic ingestion01:32:38 Immune System Triggers: How immune events may trigger Vitiligo📚ResourcesPlogging: https://en.wikipedia.org/wiki/PloggingPlogging device: https://www.amazon.de/dp/B09L2M9BPCPlogging instructions: https://stephanreichl.notion.site/2d4301f67e4c804a8be1d693086c2c14 Optimistic Nihilism by Kurzgesagt: https://youtu.be/MBRqu0YOH14 Exercise smart watch companies founding years and countries: Polar 1977 Finland, Garmin 1989 USA (since 2010 Swiss), and Coros 2014 ChinaStephan's evening routine: http://evening.polytechnist.me  Stephan's morning routine: http://morning.polytechnist.me 💡CorrectionsWhy We Sleep by Matthew Walker (https://www.goodreads.com/book/show/34466963-why-we-sleep) was published in 2017, not 2014. Stephan started sleep tracking in 2016 with an iPhone app called Sleep cycle (https://sleepcycle.com/) and therefore thought the book must have been released before (turns out he was just ahead of his time).🎙️AboutFit For Science is a deep-dive podcast hosted by two biological data scientists, Rob and Stephan, exploring the intersection of research, health tech, and data-driven lifestyle design. The hosts provide evidence-based systems, layered with practical "N=2" personal experimentation, to cut through the noise in the health and fitness industry.Learn more: https://www.fitforscience.com/Subscribe on your favorite platformsYouTube: https://www.youtube.com/@FitForScienceSpotify: https://open.spotify.com/show/56TjUxuMsPETb0kGEJ7nwfApple Podcasts: https://podcasts.apple.com/us/podcast/fit-for-science/id1863479802Amazon Music: https://music.amazon.de/podcasts/c3e54ee7-4a2c-442e-a59f-553fbfb02b11/fit-for-science⚠️Disclaimer: This podcast represents our own opinions and is for informational purposes only. It does not constitute medical or financial advice or a professional relationship.

In this inaugural episode, biological data scientists Rob and Stephan dive into the world of self-quantification. They discuss their personal setups, the reliability of popular smart rings, and share exclusive preliminary results from recent independent validation studies on sleep and fitness tracking.🔬 SummaryTwo scientists, Rob (chemist turned bioinformatician) and Stephan (mathematician turned bioinformatician), explore the intersection of technology and health.The Smart Ring Showdown: A deep dive into why the Oura Ring remains the current leader in sleep tracking despite battery durability issues and subscription hurdles.Oura technical support clarified (after some back and forth) that Oura's sleep staging is processed locally within the Oura App and is not updated or changed when the phone is connected to the internet. The ring records physiological signals and shares this data with the Oura App, which then runs the complete sleep staging pipeline offline.Sleep Study Insights: Rob shares findings from a 20-person sleep lab study (PsyArXiv preprint) comparing wearables against Polysomnography (PSG). Discover why the Apple Watch struggled with deep sleep while Oura remained remarkably consistent.The CIRCUL ring was, in fact, the worst-performing device.Participants were woken up at 3:00 am, not three hours after going to bed.Fitness Tracking (VO2max): An overview of an ongoing study at the Sports Institute in Vienna, examining how well watches from Garmin, Polar, Apple and Samsung estimate your aerobic capacityBio-Logic: A look at the "Soleus Pushup" for glucose metabolism, the medical necessity of straight teeth for longevity, and the evolutionary theories behind "rear end" hair triggered by Hank Green's hilarious short.Correction: The Soleus muscle is located on the back of the calf, and is considered part of the calf muscle group, despite not being on the shin.⏳ Chapters00:00:00 Introduction: Meet Rob and Stephan00:01:37 Smart Rings: Form Factor, Convenience, and Battery Woes00:04:17 Customer Support and Hardware Reliability in Wearables00:06:22 Rob’s Current Testing Suite: Samsung Galaxy Ring vs. Oura00:07:58 Stephan’s Routine: How a Scientist Interprets Oura Data00:10:04 Heart Rate Variability (HRV) and Temperature Baselines00:12:04 The Case for "N=2": Cross-Validating with Multiple Devices00:14:50 The Evolution of Heart Rate Tracking: PPG vs. ECG00:18:04 Comparing the App Experience: Oura, Whoop, and Samsung00:20:46 Budget Alternatives: The Amazfit Ecosystem00:22:37 Introducing "Fit4Science": The Philosophy00:24:40 News: Inside an Independent Sleep Validation Study00:27:12 Results: Oura vs. Apple Watch vs. Garmin in Sleep Staging00:30:51 Biases in Sleep Algorithms: Expectation vs. Reality00:34:33 Longevity Corner: Why Stephan Got Braces at 3400:46:59 VO2 Max Study: Testing the Accuracy of Fitness Estimates00:54:08 Human Efficiency: Energy Expenditure00:59:50 Height, Confidence, and Biological Advantages01:03:14 Body Types: Ectomorphs, Mesomorphs, and Endomorphs01:09:14 Genetic Testing and Hair Loss Prevention01:11:06 The "Elephant" in the Room: Why Rob Has 8 Bicycles01:17:14 Risk Assessment: Cycling Safety in Vienna vs. The Netherlands01:27:10 Funny Science: Why Do Humans Have Body Hair (at the “Rear End”)?01:31:34 Smells, Pheromones, and Evolutionary "Leftovers"01:34:59 Closing Thoughts and How to Support the ShowAboutFit for Science is a deep-dive podcast hosted by two biological data scientists, Rob and Stephan, exploring the intersection of research, health tech, and data-driven lifestyle design. We cut through the noise to provide evidence-based systems, layered with practical "N=2" personal experimentation.Learn more: fitforscience.comYouTube: @FitForScienceDisclaimer: This podcast represents our own opinions and is for informational purposes only. It does not constitute medical or financial advice or a professional relationship.