News

THE SIGNAL

Andy Feltovich

14 Mar 2026 — 14 min read

THE SIGNAL

Scientific Intelligence for Men’s Health & Performance

A FeltovichFit Publication · Collegium of Order & Flow

Week of March 9–14, 2026 · Issue 001 · Andy Feltovich, CISSN · CSCS · StrongFirst Elite

Each week, The Signal cuts through the noise in health, performance, and science:

What to watch?
What to ignore?
What’s “news” but isn’t new?

The Signal analyzes each topic with the IICE Framework:

Incentives. Who is being asked to believe what? Why? And why now?
Impact. Does it move the needle?
Context. How does it relate to other evidence within the discipline and across disciplines, both currently and historically?
Epistemic Authority. Is the argumentation sound and valid?

▶ What to Watch

GLP-1 Drugs: The Addiction Signal — and the Muscle Loss Nobody Is Talking About

Why It Matters A retrospective cohort study of 606,434 U.S. veterans found that GLP-1 receptor agonists reduced the risk of new substance use disorders by 14–25% across alcohol, opioids, cocaine, and nicotine — and cut drug-related deaths in half among patients with existing addiction. GLP-1 receptors are expressed in the brain’s reward circuitry, and the same dopaminergic dampening that blunts food cravings appears to blunt cravings for addictive substances.

Signal Strength This story received multi-channel confirmation in the same week: peer-reviewed BMJ data, NPR national coverage, and an FDA warning letter to Novo Nordisk for failure to report serious adverse events — including patient deaths — within the required 15-day window. The signal you are not hearing: the NEJM STEP 1 trial found that roughly 40% of weight lost on semaglutide is lean mass, not fat. For the executive male over 40, that is a body composition problem on a slow timer.

Prediction GLP-1s will carry an on-label addiction indication within 3–5 years. The immediate play: structured resistance training and adequate protein are non-negotiable adjuncts for anyone on these drugs. See the deep-dive below.

Headlines: BMJ, Mar 4, 2026 · NPR, Mar 5, 2026 · FDA Warning Letter, Mar 5, 2026

Wearables + HRV + Sleep Tracking — The Data Is Ready. The Interpretation Isn’t.

Why It Matters ACSM ranked wearable technology the #1 fitness trend for the fifth consecutive year, surveying 2,000 clinicians and exercise professionals. Oura Gen 4 validation studies show near-clinical accuracy for sleep staging. The executive cohort over-indexes on device ownership and under-indexes on acting on the data. HRV, sleep quality, and resting heart rate together paint a daily readiness picture that changes what you should do Monday morning — if you know how to read it.

Signal Strength Device accuracy has matured to where the technology is no longer the limiting factor. The gap is coaching competence: the practitioner who can translate a readiness score into a training decision owns the next decade of performance coaching.

Prediction Wearable data will become a standard intake variable in executive health programs within three years — the same way blood panels are today. The coaches and clinicians building that literacy now will be the ones with waiting lists.

Headlines: ACSM Top Fitness Trends 2026

Testosterone and Men’s Hormonal Health — The Space Nobody Is Doing Honestly

Why It Matters Population-level testosterone has declined roughly 1% per year independent of aging, a trend documented across three decades in the Massachusetts Male Aging Study. The 40+ executive cohort is the primary affected demographic. The information space is dominated by TRT clinic marketing on one end and bro-science on the other, and nobody is giving this audience rigorous, unconflicted analysis.

Signal Strength This story is growing quietly across clinical and social channels, under-covered relative to GLP-1, and represents a high pain point for this audience. Lifestyle interventions — sleep quality, progressive strength training, stress management, and body composition improvement — move the needle meaningfully before TRT is warranted.

Prediction The men’s hormone space will bifurcate: TRT mill clinics versus evidence-based, lifestyle-first protocols. The Signal is planting a flag on the latter.

Headlines: Travison et al., JCEM 2007

✕ What to Ignore

RFK / Food Dyes Ban — Policy Noise, Not Science Signal

Why It’s Spiking Political momentum from the MAHA movement has produced real legislative action: West Virginia became the first state to ban synthetic dyes, and roughly 40% of packaged food companies have made voluntary reformulation commitments.

Why It’s Noise Reuters found that almost none of those companies have actually reformulated their products. The behavioral literature on synthetic dyes in adults is essentially nonexistent, and regulatory action does not equal scientific validation. If you eat real food, this problem is already solved.

What Would Change My Mind Double-blind RCTs showing consistent behavioral or physiological effects at real-world exposure levels in adults.

Headlines: Reuters, Jan 28, 2026 · KFF Health News

Beef Tallow Skincare / Carnivore Beauty

Why It’s Spiking This is a classic TikTok meme cycle: a simple, counterintuitive claim that is photogenic and easy to film. The format rewards novelty, not evidence.

Why It’s Noise No peer-reviewed dermatology literature supports topical tallow as a therapeutic intervention. The American Academy of Dermatology consensus is unchanged, and Lung.org issued a direct consumer warning this week. High social velocity, zero clinical signal, and no relevance to this audience’s performance goals.

What Would Change My Mind A single RCT from a credible dermatology institution demonstrating benefit over a controlled comparator.

Slow Wellness / The Over-Optimization Backlash

Why It’s Spiking The Global Wellness Summit named it a top 2026 trend, luxury brands including Nike and On Running are repositioning around “softness,” and TikTok somatic release content is generating significant traffic.

Why It’s Noise This is a luxury brand marketing story dressed up as a wellness movement. The underlying stress physiology is real. The product being sold around it is expensive experiences and aesthetic repositioning. Executive high performers need optimization frameworks, not permission to under-perform.

What Would Change My Mind If the somatic regulation literature develops a clinical evidence base comparable in rigor and scale to structured exercise interventions.

Headlines: Global Wellness Summit, Future of Wellness 2026

↻ What’s “News” but Isn’t New

Fibermaxxing — Fiber Is the New Protein

Current Trend TikTok is driving fiber-focused product launches across grocery and beverages, with CNN, Good Housekeeping, and Whole Foods positioning fiber as 2026’s breakout nutrient. The GLP-1 hook generating the most coverage: natural fiber stimulates endogenous GLP-1 production.

Historical Analog The core fiber science — LDL reduction, blood sugar stabilization, gut microbiome support — has been established since Burkitt and Trowell in the 1970s. FDA dietary fiber recommendations have moved negligibly in 30 years.

What’s Actually Different The GLP-1 mechanism framing is genuinely new, and the product innovation is real. The underlying nutritional principle is five decades old. Know the difference.

Headlines: CNN, Jan 25, 2026 · Kerry Health & Nutrition Megatrends

Zone 2 Cardio for Longevity — Soviet Endurance Science Returns

Current Trend Peter Attia, Thomas DeLauer, and YouTube educators are driving massive social velocity around Zone 2, positioning it as a discovery in longevity and metabolic health for a new generation of athletes and executives.

Historical Analog Soviet sports science (Lydiard, Selouyanov) and East German endurance programs established the metabolic underpinning of low-intensity training in the 1960s–80s. Maffetone formalized the fat-burning zone in the 1980s. This principle is 60 years old.

What’s Actually Different The mitochondrial density research is maturing with better measurement tools, and Mandsager et al. (JAMA, 2018, n=122,007) established VO₂max as the strongest independent predictor of all-cause mortality. The longevity framing is new. The training principle is not.

Neurowellness / Nervous System Regulation

Current Trend The Global Wellness Summit named nervous system regulation a top 2026 trend. Polyvagal theory is entering mainstream consumer wellness, and TikTok somatic release content is going viral — largely to an audience with no idea the underlying theoretical framework is under serious scientific challenge.

Historical Analog This is Polyvagal Theory (Porges, 1994), Somatic Experiencing (Levine, 1970s), and MBSR (Kabat-Zinn, 1979) in new consumer packaging. In February 2026, Grossman and 39 co-signatories published in Clinical Neuropsychiatry declaring Polyvagal Theory “untenable” as a mechanistic account of autonomic function.

What’s Actually Different The tools work. Breathwork, HRV biofeedback, and MBSR have strong RCT outcome data independent of whether the polyvagal mechanism is correct. The theory is contested. The applications are not. See Further Reading below for Porges’ primary texts.

Headlines: Global Wellness Summit, Future of Wellness 2026

■ Deep Dive — Issue 001

GLP-1 Drugs and Addiction — The Unexpected Signal

What a 600,000-person study means for the future of addiction medicine, the economics of drug development, and why the muscle loss story matters more than the weight loss headline.

A retrospective cohort study of 606,434 U.S. veterans — the largest observational study of its kind — found that GLP-1 receptor agonists reduced the risk of new substance use disorders by 14–25% across alcohol, opioids, cocaine, and nicotine, and cut drug-related deaths in half among patients with existing addiction.^[1] This is not a randomized controlled trial, but at 600,000 participants across multiple substances, the signal is hard to dismiss. Mechanistically, it makes sense: GLP-1 receptors are expressed in the brain’s reward circuitry, and the same dopaminergic dampening that reduces food cravings appears to reduce cravings for addictive substances.

A note on mechanism: GLP-1s are not a substitute for benzodiazepines in alcohol detox or methadone in opioid maintenance. They don’t touch withdrawal physiology. The signal is in what happens after detox: reduced craving, reduced relapse, reduced harm — across multiple substances simultaneously. That cross-substance effect is what makes this genuinely novel. Current addiction drugs (naltrexone, acamprosate) don’t work that way.

The incentives are clear: Novo Nordisk’s U.S. patent on semaglutide expires in 2032. The substance use disorder (SUD) treatment market is $42 billion annually — with only 2% of eligible patients currently prescribed any medication. An FDA approval for addiction wouldn’t just open a new revenue category — it would build a clinical moat.^† Generic biosimilars can only copy approved indications. Every new pathology Novo and Lilly can lock in before the patent cliff forces generics to run their own expensive trials before they can compete. Eli Lilly is already running two Phase 3 trials of a dedicated GLP-1 addiction compound. The race is on.

The GLP-1 revolution was never just a drug launch. It was a class launch — the first since statins redrew cardiovascular medicine in the 1990s — and unlike statins, it’s a class launch across multiple disease categories: obesity, diabetes, addiction, neurodegeneration. The scope and scale of such conquest makes the side effects — known and unknown — that much more troubling. One of the more well-known, short-term side effects is that approximately 40% of weight loss comes from lean muscle — not fat, as confirmed by multiple randomized controlled trials.^{[2, 3]} The fix is not complicated: lifestyle modification as a first line of defense, strategic use of GLP-1 agonists only when necessary — and structured resistance training and nutrition — including adequate protein — always.

^† In investment language, a moat is a durable competitive advantage that protects profits over time — the term originates with Warren Buffett and is formalized in H. Brilliant and J. J. Collins, Why Moats Matter: The Morningstar Approach to Stock Investing (Wiley, 2014). The strategic underpinning is M. E. Porter’s Five Forces framework, which identifies barriers to entry as one of the five forces that determine industry profitability — see M. E. Porter, On Competition (Harvard Business Review Press, Updated ed., 2008). See Further Reading below for both.

Sleep Wearables: Good Servant — Poor Master

Sleep trackers are useful tools. They are not polysomnography. Here is what they actually measure, what the science says about what they get right, and why knowing the difference matters more than your sleep score.

We’re entering the second stage of sleep wearables. The first stage was making scientifically validated metrics commercially feasible. The second stage will be interpretation and wisdom — knowing not just how to use the metrics, but when. But first, a whirlwind recap of how we got here.

The Gold Standard You Don’t Have

Electronic sleep measurement isn’t new. The discipline was pioneered by Nathaniel Kleitman in 1937 with the use of electroencephalography to record brain activity during sleep.^[4] Since then, sleep scientists have progressively added more measuring devices to more body parts to better triangulate and taxonomize the physiological states that are collectively known as “sleep”:

Electro-oculography (EOG) — eye movement, which led to the discovery of Rapid Eye Movement (REM) sleep^[5]
Electromyography (EMG) — muscle tone
Electrocardiography (ECG) — cardiac rhythm and pulse oximetry

That bundle of laboratory measurements is collectively known as polysomnography (PSG) — the gold standard — which allows a trained practitioner to score every 30-second epoch of your night into one of five stages: Wake, N1, N2, N3 (slow-wave/deep), and REM. William Dement, Kleitman’s student and the originator of that nomenclature, joked that had he known those terms would persist, he would have thought of something sexier.

Your Oura Ring, WHOOP strap, or Apple Watch does none of that. The breakthrough that made wearables feasible came in the 1970s with wrist actigraphy — motion detection — followed by skin temperature and photoplethysmography (PPG), the optical heart rate sensor on the back of your ring. Wearables combine those measurements with proprietary algorithms to infer what sleep stage you might be in — not the same league as PSG. As Brandon Marcello puts it: the gap in error is the difference between a DEXA body composition scan and asking someone across the room to guess your body fat percentage.^[6]

What Do Sleep Wearables Actually Do?

The following is adapted from an article by sleep physician and FeltovichFit Podcast guest Dr. Muhammad Usama.^{[7, 8]} For total sleep time — whether you were asleep or awake — consumer wearables perform reasonably well. Oura Ring Gen 3 and Gen 4 show approximately 94% sensitivity for sleep detection. WHOOP is in the same range. The wheels come off with specificity — distinguishing quiet wakefulness from actual sleep. Fitbit Inspire 2 clocked 94% sensitivity but only 13% specificity in one validation, meaning it logged nearly every quiet period as sleep. If you lie awake at 3 AM for 40 minutes and your tracker doesn’t know it, your reported sleep total is fiction. A 2025 meta-analysis of 24 studies found that popular wearables underestimate total sleep time by roughly 17 minutes and sleep efficiency by 5%, while overestimating wake-after-sleep-onset by about 13 minutes compared to PSG.

Four-stage scoring (light, deep, REM, wake) is where the wheels fall off. The best-performing consumer devices show 75–80% agreement with PSG. Oura Ring Gen 3 showed stage-scoring accuracy between 75–91% depending on the stage — the best peer-reviewed numbers in the consumer space. WHOOP showed approximately 64% overall agreement with PSG on four-stage scoring. The Apple Watch Series 8 could distinguish sleep versus wake adequately but fared poorly on estimating sleep stages.

Metric	Polysomnography (PSG)	Consumer Wearables (Oura, WHOOP, Apple Watch)
Sleep Staging	EEG-based; highly accurate	Inferred from movement & HR; moderate agreement
Total Sleep Time	Very accurate	Generally good for healthy individuals
Sleep Latency	Accurate	Often underestimated
Sleep Apnea Detection	Standard (AHI)	Most devices lack reliable apnea detection
Adapted from Usama (2025).^[8] Sensitivity = true positive rate for sleep; specificity = true negative rate for wake.

The Fatigue Science ReadiBand — a technology representing $37 million in DoD-funded research and 25 years of development — achieves approximately 93% agreement with PSG, making it the most validated device in the consumer-adjacent market. However, it’s expensive: $649 for the device and a one-year subscription as of this writing, plus $599 for a 12-month renewal (to which I respectfully declined) — and the app isn’t as good as Oura’s.

Orthosomnia: The Word You Need to Know

Knowledge is knowing a tomato is a fruit. Wisdom is knowing not to put it in a fruit salad.

You can know your deep sleep percentage down to a decimal point and make yourself worse. Clinicians have a name for this: orthosomnia — a preoccupation with optimizing tracker data to the point where the monitoring itself disrupts sleep. The patient extends time in bed to chase a higher efficiency score, which — counterproductively — typically lowers efficiency. The anxiety about the score impairs sleep onset. The vigilance required to monitor your own wakefulness is neurologically incompatible with falling asleep. If you are the kind of person who optimizes everything, you are at elevated risk for this. Wearables are an adjunct to sleep hygiene — not a substitute or scorecard for it.

Three Questions That Don’t Require a Wearable

Before you interpret a single score from any device, answer these honestly:

Can you fall asleep at roughly the same time each night without pharmacological help — no alcohol, no OTC drugs, no prescription sleep aids?
Do you wake up on time, refreshed, without an alarm clock?
Can you get through the day without depending on stimulants?

If you answer yes to all three, your sleep is functioning. The wearable can add texture. If you answered no to any of them, no device will fix that. And the device may, in fact, distract you from fixing it.

The IICE read: Wearables are converging to the theoretical limit of what can be achieved without full PSG in a sleep lab under a trained practitioner. Fatigue Science is the “best” and offers customization — useful if, for example, you own a heavy equipment company and need to ensure operators are rested for safety and liability purposes. Otherwise, Oura is sufficient and comes with a better price and app. Assess the score in conjunction with how you’re feeling and behaving, and understand that wearables can only approximate sleep stages. If a wearable says you’re sleeping well but you wake up exhausted, believe your body. The wearable watches you sleep. It doesn’t sleep for you. Last, it bears repeating: do not try to diagnose or treat obstructive sleep apnea (OSA) or any other sleep disorder with a wearable.

■ References · Further Reading · Additional Resources

References — Issue 001

[1] M. Cai, T. Choi, Y. Xie, and Z. Al-Aly, “Glucagon-like peptide-1 receptor agonists and risk of substance use disorders among US veterans with type 2 diabetes: cohort study,” BMJ, vol. 392, e086886, Mar. 2026. https://doi.org/10.1136/bmj-2025-086886

[2] D. Pantazopoulos, E. Gouveri, D. Papazoglou, and N. Papanas, “GLP-1 receptor agonists and sarcopenia: Weight loss at a cost? A brief narrative review,” Diabetes Res. Clin. Pract., vol. 229, p. 112924, Nov. 2025. https://doi.org/10.1016/j.diabres.2025.112924

[3] J. P. H. Wilding et al., “Once-Weekly Semaglutide in Adults with Overweight or Obesity,” N. Engl. J. Med., vol. 384, no. 11, pp. 989–1002, Mar. 2021. https://doi.org/10.1056/NEJMoa2032183

[4] M. H. Kryger, T. Roth, and C. A. Goldstein, Kryger’s Principles and Practice of Sleep Medicine, 7th ed. Philadelphia: Elsevier, 2022. Hardcover Kindle

[5] W. C. Dement, “Knocking on Kleitman’s Door: The View from 50 Years Later,” Sleep Medicine Reviews, vol. 7, no. 4, pp. 289–292, 2003. https://doi.org/10.1053/smrv.2003.0279

[6] B. Marcello, “Sleep – The Only True ‘Fix-All’ for Health and Performance,” NSCA, May 15, 2020. [Online]. https://www.youtube.com/watch?v=WKt2LoHaCp4

[7] A. Feltovich, “Sleep as a Superpower: Optimizing Rest, Wakefulness, and Longevity with Dr. Muhammad Usama,” FeltovichFit Podcast, 2025. Spotify

[8] M. Usama, “Can Wearables Truly Transform Sleep Health, or Are We Just Watching Ourselves Sleep?” LinkedIn Pulse, Jun. 18, 2025. LinkedIn