The Wellness Brew - Issue 03

We live in a culture that quietly rewards sacrifice. Working late is dedication. Running on five hours is resilience. Getting by on less is a badge of discipline. The science says otherwise — and the gap between what most people believe about sleep and what the research actually shows is significant. This week, we dig into what sleep is really doing, what chronic deprivation is costing you, and what the evidence says to do about it. But first, we filtered the noise — here's what's worth knowing this week.

Chronic Stress, NAD⁺, and Liver Cancer — A 2026 study published in Nature Metabolism identified a specific biological pathway linking chronic psychological stress to liver cancer progression. Researchers found that stress-induced catecholamine signaling suppresses a key liver enzyme involved in the kynurenine pathway, diverting metabolism away from NAD⁺ synthesis. The resulting NAD⁺ depletion impairs the CD8+ T cells responsible for immune surveillance — essentially disabling the liver's ability to detect and destroy cancer cells. The findings were corroborated with data from human liver cancer patients, though it is important to note that the primary mechanistic experiments were conducted in animal models, and large-scale human clinical trials have not yet confirmed causation. Metabolic researcher Nick Norwitz (@nicknorwitz), who holds a PhD from Oxford and an MD from Harvard, highlighted the study, noting that the implications extend well beyond cancer — the same NAD⁺ depletion pathway has been linked to Alzheimer's disease and broad metabolic dysfunction. [Nature Metabolism, 2026]

Hearing Loss and Dementia Risk — Hearing loss affects more than one in three adults over 60 — and a growing body of research suggests it may be one of the most underappreciated drivers of cognitive decline. The landmark prospective study that established this link, published in JAMA Neurology and conducted through the Baltimore Longitudinal Study of Aging, found that hearing loss independently increases the risk of all-cause dementia, with risk rising in line with severity. A 2024 meta-analysis of 50 studies encompassing over 1.5 million participants reinforced the finding, estimating a 16% increase in dementia risk for each 10-decibel worsening of hearing. The proposed mechanism: hearing loss reduces cognitive stimulation, increases social isolation, and may accelerate atrophy in auditory processing regions of the brain — all factors that converge on accelerated cognitive decline. As highlighted by @brainjojosh at the Institute for Performance Neurology, this is an area of brain health that most people are not paying nearly enough attention to. [JAMA Neurology]

Fiber as a Defense Against Microplastics — Research suggests dietary fiber may be one of the most practical tools for limiting the amount of microplastics your body actually absorbs. Dr. Rhonda Patrick (@foundmyfitness) has highlighted two distinct mechanisms by which fiber helps. Fermentable fiber — found in oats, mushrooms, onions, fruits, and artichokes — creates a viscous gel in the gut that encapsulates microplastic particles and prevents their absorption. Insoluble fiber speeds up digestive transit, helping push plastic particles through the system before they have a chance to be absorbed. The practical takeaway: a high-fiber diet built around whole plant foods does more than support gut health — it may serve as a meaningful first line of defense against microplastic accumulation. [Rhonda Patrick / FoundMyFitness]

Sleep: The Most Underrated Performance and Longevity Tool

Insufficient sleep was a stronger predictor of shorter life expectancy than diet, physical activity, or social isolation — that is according to a 2025 study from Oregon Health & Science University that analyzed CDC survey data across all 3,143 counties in the United States. [1]  For most people, how they sleep matters more to how long they live than how they eat or how often they exercise. And yet sleep remains the one pillar of health that modern culture treats as optional — something to sacrifice when things get busy, a sign of discipline when skipped, a luxury when prioritized.

It is none of those things. It is a biological necessity with consequences that compound over time.

What sleep actually does

Sleep is not a passive state. It is one of the most metabolically active and biologically productive periods of your day. During sleep, the brain consolidates and stores the information acquired during the day — a process that is essential for learning, memory, and decision-making. 

Sleep is also when the body executes its most significant hormonal work. The largest daily pulse of growth hormone — which drives tissue repair, muscle recovery, and cellular maintenance — is released during deep sleep. Testosterone, cortisol, leptin, and ghrelin are all regulated in part by sleep quality and duration. Disrupt the sleep, and you disrupt the hormonal architecture that governs energy, mood, appetite, and recovery. [2]

The immune system uses sleep as its primary repair window. During sleep, the body produces and deploys cytokines, T-cells, and other immune mediators that maintain resistance to pathogens and support long-term immune function. Sleep-deprived individuals mount measurably weaker responses to vaccines and infections. [3]

And sleep is when the cardiovascular system gets its nightly reset. Blood pressure drops during sleep — a process known as nocturnal dipping — that is essential for vascular health. When sleep is disrupted, that reset doesn't happen, and blood pressure remains elevated for longer each day. [4]

Finally, and directly relevant to last week's issue on chronic inflammation: sleep is a primary regulator of your inflammatory state. Restorative sleep actively suppresses pro-inflammatory cytokines including CRP and IL-6. Poor sleep drives them up. The relationship between inflammation and sleep is bidirectional and self-reinforcing — and it is one of the clearest biological pathways connecting poor sleep to several chronic diseases. [3]

What chronic sleep deprivation is doing to your body

The long-term picture is well-documented across decades of research.

Cardiovascular disease. Sleep deprivation activates the sympathetic nervous system — the body's fight-or-flight system — which elevates heart rate, raises blood pressure, and accelerates atherosclerosis. A systematic review found that short sleep duration was associated with a 45% increased risk of coronary heart disease. The American Heart Association added sleep to its "Life's Essential Eight" framework for cardiovascular health in 2023, placing it alongside diet, exercise, and smoking status. [4]

Metabolic health. Insufficient sleep disrupts the hormones that regulate hunger — increasing ghrelin, which drives appetite, while decreasing leptin, which signals satiety. It also impairs insulin sensitivity and glucose metabolism, increasing the risk of obesity and type 2 diabetes. [6]

Hormonal disruption. Chronic sleep deprivation suppresses growth hormone release, impairs testosterone production, and sustains elevated evening cortisol levels — a hormonal profile that accelerates muscle breakdown, fat storage, and stress reactivity.

Cognitive decline. Persistent short sleep — under six hours per night — in adults over 50 has been associated with a 30% increased risk of dementia. The proposed mechanism involves the accumulation of metabolic waste products in the brain, including the amyloid-beta and tau proteins associated with Alzheimer's disease, when the brain's clearance systems are unable to complete their work. [7]

One night is enough to do damage

One of the most persistent myths about sleep is that occasional poor nights are harmless — that you can pull a late one on Wednesday, stay out Friday, work through Sunday, and simply catch up later. 

Research published in Frontiers in Behavioral Neuroscience tells a different story. The study found that a single 24-hour period of sleep deprivation increased inflammatory markers CRP and IL-6, elevated negative emotional states including anxiety, fatigue, and depression, and produced measurable deficits in cognitive performance — all within one sleepless cycle. [5]

The weekly late night, the regular early alarm after a short sleep, the one night you push through — none of these are neutral events. Each one disrupts circadian rhythm, shifts immune function, elevates inflammatory markers, and impairs the following day's cognitive and hormonal performance. [2]

How much sleep do you actually need — and what kind

Seven to nine hours per night is the evidence-based range for adults, consistent across the American Academy of Sleep Medicine, the Sleep Research Society, and the CDC. But total sleep time is only part of the equation. The quality and composition of that sleep matters enormously.

A full night of sleep consists of repeating 90-minute cycles, each containing several distinct stages. Two of those stages are particularly critical:

Deep sleep (Stage 3/slow-wave sleep) should represent approximately 13–23% of your total sleep time — roughly 1 to 2 hours for most adults sleeping 7–9 hours. This is when the body carries out its most intensive physical repair work: tissue regeneration, immune strengthening, and the release of growth hormone. It is concentrated in the first half of the night, which means cutting sleep short — even by an hour or two — disproportionately costs you deep sleep.  [8]

REM sleep should represent approximately 20–25% of your total sleep time — roughly 1.5 to 2 hours per night. REM is the brain's maintenance phase: memory consolidation, emotional processing, and cognitive restoration all happen here. REM sleep is concentrated in the latter half of the night and early morning hours, so setting your alarm 90 minutes earlier than normal doesn't just mean less sleep — it means missing out on almost all REM sleep.  [8]

The practical implication: you can't meaningfully compress sleep. Seven hours that are fragmented or cut short at both ends is not the same as seven hours of uninterrupted, complete cycles. And the person who says they "function fine on five hours" almost certainly isn't — research consistently shows that chronically sleep-deprived people lose the ability to accurately gauge their own impairment as the deficit accumulates.

The evidence is consistent and unambiguous: sleep is not a passive recovery tool or a negotiable variable. It is the biological foundation on which every other health behavior rests. You cannot out-exercise poor sleep, out-supplement it, or out-discipline it. Seven to nine hours of quality, uninterrupted sleep — every night — is one of the most powerful things you can do for your long-term health. The question is how to actually get there.

Three things you can do this week:

1. Anchor your sleep with consistent bed and wake times. Your circadian rhythm is the biological clock that governs when you fall asleep, how deeply you sleep, and how rested you wake up. Keeping consistent bed and wake times — including weekends — is the single most impactful habit you can build around sleep. Irregular schedules, even by an hour or two, disrupt this rhythm and degrade sleep quality over time without you realizing it. Start here before trying anything else.

2. Cut off caffeine by early afternoon. Caffeine has a half-life of 5–7 hours, meaning a 3pm coffee still has half its stimulating effect in your system at 8–9pm — directly suppressing the deep sleep stages that concentrate in the first half of the night. Most people significantly underestimate how much their afternoon caffeine is costing them in sleep quality. A practical starting point: nothing caffeinated after 2pm, and adjust from there based on how you feel.

3. Optimize your sleep environment. Three variables have an outsized impact on sleep architecture and are almost entirely within your control. First, temperature: your core body temperature must drop to initiate and sustain sleep — a bedroom kept at 65–68°F meaningfully improves both sleep onset and deep sleep duration. Second, light: reduce bright and blue-spectrum light exposure in the 1–2 hours before bed to preserve melatonin production. Third, timing: avoid large meals within 2–3 hours of bedtime — late eating elevates core body temperature and disrupts the deep sleep stages you need most. None of these require a supplement or a device. They just require consistency.

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Wellness, filtered.

The Wellness Brew

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Disclaimer: The Wellness Brew is for informational purposes only and does not constitute medical advice. The content published here is not intended to diagnose, treat, cure, or prevent any disease or health condition. Always consult a qualified healthcare professional before making any changes to your diet, supplement routine, or lifestyle.