Kat Fu, M.S., M.S.

Why Does One Glass of Wine Ruin Your Sleep During Menopause?

Sleep & 3AM Wakeups, Women's Hormones and Sleep /

Alcohol disrupts menopause sleep through three pathways: it suppresses REM architecture even at low doses; it triggers vasodilation in a body whose thermoneutral zone is already narrowed by estrogen depletion, raising hot flash frequency; and it alters estrogen metabolism through hepatic enzyme interactions, with the strongest hormonal effects occurring when gonadotropins are elevated — the […]

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Does NAD+ IV Therapy Improve Sleep? What the Evidence Shows

Metabolic Sleep, Sleep & 3AM Wakeups /

No controlled human trial has measured whether IV NAD+ infusions improve sleep. The Gindri 2024 review of 10 NAD-related RCTs evaluated fatigue, sleep, and anxiety endpoints but found evidence insufficient for firm recommendations; none of the trials used IV delivery with sleep as a primary outcome. A 2026 pilot comparing IV NAD+ to IV NR

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Is Your 3am Wakeup a Metabolic Emergency — Blood Sugar, Cortisol, and Mitochondrial Strain?

Metabolic Sleep, Sleep & 3AM Wakeups /

The 2-4am window is when your metabolism is vulnerable. Blood glucose reaches its overnight nadir, cortisol peaks at approximately 3:40am biological time, and liver glycogen stores are at their lowest. When blood sugar drops below a critical threshold, counter-regulatory hormones fire — epinephrine, cortisol, glucagon — and these stress hormones trigger arousal. In metabolically healthy

Is Your 3am Wakeup a Metabolic Emergency — Blood Sugar, Cortisol, and Mitochondrial Strain? Read Post »

Does Inflammaging Disrupt Sleep After 50?

Inflammatory Sleep, Sleep & 3AM Wakeups /

Yes. Inflammaging – the chronic, low-grade inflammation that increases with age – can contribute to poorer sleep architecture by reducing slow-wave sleep, increasing awakenings, and lowering sleep efficiency. IL-6, TNF-alpha, CRP, and related inflammatory mediators tend to rise with aging as senescent cells and metabolic changes contribute to pro-inflammatory signaling, including the senescence-associated secretory phenotype

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Does Poor Sleep Damage Your Gut Microbiome? The Reinforcing Cycle Between Insomnia and Dysbiosis

Autonomic Sleep, Sleep & 3AM Wakeups /

A 2026 meta-analysis of 20 studies found sleep deprivation reduces gut microbiome Shannon diversity in rodent models (standardized effect -1.27) and increases the Firmicutes-to-Bacteroidetes ratio in rodent models (+2.60) — a shift toward inflammation-associated species (Supasitdikul et al., 2026). Human studies showed nonsignificant trends in the same direction. A Mendelian randomization study in 386,533 individuals

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Does Your Sleep Tracker Accuracy Matter? What Oura, WHOOP, and Apple Watch Get Right and Wrong About Sleep Stages

Autonomic Sleep, Sleep & 3AM Wakeups /

Written by Kat Fu Consumer sleep trackers are reasonably accurate for detecting whether you are asleep or awake (86-93% agreement with polysomnography) but less accurate for classifying individual sleep stages (50-65% agreement). A 2024 validation study found Oura Ring Gen3 achieved 76-80% sensitivity across sleep stages – the best of three devices tested – while

Does Your Sleep Tracker Accuracy Matter? What Oura, WHOOP, and Apple Watch Get Right and Wrong About Sleep Stages Read Post »

Which Parts of Your Eye Age Permanently — and What Accelerates the Damage?

Circadian Sleep, Sleep & 3AM Wakeups /

Several structures in your eye cannot repair or regenerate themselves. Corneal endothelial cells decline from approximately 5,000 per mm² at birth to a decompensation threshold near 500 cells per mm² — and every UV exposure damages cells that cannot be replaced. Retinal melanin declines 2.5-fold over a lifetime, and the remaining melanin undergoes photooxidation, reversing

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Does Ozempic Muscle Loss Affect Your Sleep? Sarcopenia, Temperature, and Deep Sleep

Metabolic Sleep, Sleep & 3AM Wakeups /

In semaglutide trials, lean-mass reductions have ranged from near 0% to about 40% of total weight lost, with broader GLP-1-based therapy reviews showing wide variation. Skeletal muscle is one of the body’s major heat-generating tissues. When lean mass declines, thermogenic capacity may fall, and the evening temperature changes that support sleep onset may become less

Does Ozempic Muscle Loss Affect Your Sleep? Sarcopenia, Temperature, and Deep Sleep Read Post »

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