Sleep & 3AM Wakeups | The Longevity Vault

Does Your Gut Decide Whether Your NAD+ Supplement Works?

Gut bacteria perform the rate-limiting step in NAD+ precursor metabolism. Isotope-tracing studies show that orally ingested NR and NMN are not absorbed intact in large quantities. Instead, gut bacteria expressing the nicotinamidase enzyme (pncA) convert nicotinamide into nicotinic acid, which the liver then uses to synthesize NAD+ through the Preiss-Handler pathway. In germ-free mice lacking […]

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Can CoQ10 and PQQ Supplements Improve Your Sleep?

Randomized controlled trial evidence supports CoQ10 for sleep improvement at doses of 100-200 mg/day. A 2025 RCT found 100 mg/day CoQ10 improved sleep quality in six weeks (p

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

Metabolic Sleep, Sleep & 3AM Wakeups / Kat Fu, M.S., M.S.

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

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Can Vagus Nerve Stimulation Stop Mast Cell Insomnia?

Autonomic Sleep, Sleep & 3AM Wakeups / Kat Fu, M.S., M.S.

Vagus nerve stimulation may address mast cell insomnia at its autonomic root. The vagus nerve physically innervates mast cells in the gut and directly regulates their degranulation. When vagal tone is low, this regulatory input fails and mast cells release histamine and other mediators unchecked. Two randomized controlled trials of transcutaneous auricular vagus nerve stimulation

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How Do Probiotics Reach Your Brain? The Vagotomy Evidence

Autonomic Sleep, Sleep & 3AM Wakeups / Kat Fu, M.S., M.S.

When scientists severed the vagus nerve in mice and gave them the probiotic Lactobacillus rhamnosus JB-1, the behavioral and stress-hormone effects disappeared — anxiety reduction and corticosterone suppression required an intact vagus nerve (Bravo et al., 2011). Electrophysiological recordings showed JB-1 fires vagal afferent neurons within minutes of gut contact (Perez-Burgos et al., 2013). A

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Can Vagus Nerve Stimulation Devices Improve Insomnia? What the Research Shows

Autonomic Sleep, Sleep & 3AM Wakeups / Kat Fu, M.S., M.S.

Transcutaneous auricular vagus nerve stimulation (taVNS) improved insomnia in multiple randomized controlled trials. A 2024 Journal of the American Medical Association (JAMA) Network Open trial found taVNS reduced insomnia severity by 4.2 points more than sham stimulation over 8 weeks, with benefits sustained through 20 weeks. A 2025 meta-analysis pooling 6 trials (336 participants) confirmed

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How Does UV Light Age Your Eyes? The Two Types of Lens Damage That Affect Your Vision and Your Sleep

Circadian Sleep, Sleep & 3AM Wakeups / Kat Fu, M.S., M.S.

UV light ages the eye’s lens through two distinct mechanisms — and both disrupt your sleep. UV-B radiation photooxidizes crystallin proteins at the lens periphery, producing cortical cataracts. Meanwhile, kynurenine metabolites accumulate in the lens nucleus throughout life, yellowing it progressively — a process UV-A radiation accelerates. Both types of damage filter out the 480

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Why Does Eastbound Jet Lag Last Longer Than Westbound — and What Determines Recovery Rate?

Circadian Sleep, Sleep & 3AM Wakeups / Kat Fu, M.S., M.S.

Eastbound jet lag lasts roughly twice as long per time zone crossed as westbound. The reason is physiological: the human circadian period averages slightly longer than 24 hours, making day extension (westward) mechanically easier than day compression (eastward). A 2024 review of 23 studies confirmed the asymmetry — approximately 0.5 days per time zone westward,

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Why Does Sleep Repair Your DNA — And Burn Through Your NAD+ to Do It?

Metabolic Sleep, Sleep & 3AM Wakeups / Kat Fu, M.S., M.S.

Sleep is when neurons repair DNA lesions that build up during wakefulness. The enzyme PARP1 detects DNA breaks, consumes NAD+ to initiate repair, and promotes sleep pressure to create the conditions repair requires. In zebrafish and mice, six hours of consolidated sleep reduced neuronal DNA lesions, and PARP1 inhibition reduced NREM sleep by 33%. This

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Do Your Mitochondria Control When You Sleep? and Why Does It Break Down After 40?

Metabolic Sleep, Sleep & 3AM Wakeups / Kat Fu, M.S., M.S.

Mitochondria generate the molecular pressure that makes you sleepy. A 2025 Nature study found that mitochondrial fragmentation and ATP accumulation in sleep-control neurons directly drive sleep onset — and that manipulating mitochondrial shape bidirectionally controls sleep duration. After 40, mitochondrial DNA copy number reductions, antioxidant defenses weaken, and the ROS (oxygen-derived molecules involved in redox

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