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Brett Fish

Field Notes

Everything I've tested, written down.

n=1 experiments, sleep science in plain English, and honest reads on the research. No hype, no miracle claims — just what survived contact with my own data.

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In the lab — coming soon

Environmental health

I Thought 'Forever Chemicals' Were Wellness Panic. Then I Read the EPA.

PFAS sounded like influencer fear-mongering to me — until I went to the actual government sources. They're real, they're in your blood, and the agencies are not being subtle about it.

Recovery

What Your HRV Score Actually Tells You (and What It Doesn't)

Your tracker hands you a heart-rate-variability number every morning and acts like it's a grade. It's useful — but only if you stop comparing it to anyone else's.

Sleep Science

How Late Is Too Late for Coffee? The 6-Hour Rule, Tested

Caffeine has a ~5–6 hour half-life, so your afternoon coffee is still half in your system at bedtime. A clean trial found it wrecks sleep even when you can't feel it. Here's the honest cutoff.

Sleep Science

Why You Wake Up at 3 AM (and the Four Things That Fixed It for Me)

Middle-of-the-night waking has a short list of usual suspects — blood sugar, alcohol, temperature, and a stressed-out nervous system. Here's how I worked through mine.

Supplements

Creatine for Sleep? Not Really — but This One Study Is Wild

Creatine won't help you sleep. But a 2024 study found a single big dose blunted the cognitive hit of a sleepless night — a different, stranger, and more interesting thing.

Circadian

I Started Getting Morning Light on Purpose. Here's Why I Keep Doing It.

It's the most low-tech sleep lever I've got, it costs nothing, and the research behind it is some of the least hand-wavy in this whole space. You just have to go outside.

N=1 Experiment

The Bedroom Temperature Experiment: 18 Nights, One Thermostat

Thermoregulation might be the most underrated sleep lever there is. I moved the thermostat in 1-degree steps and let my tracker pick the winner.

Supplements

Magnesium for Sleep: What I Found Digging Past the Hype

It's the internet's favorite sleep supplement, and the evidence is thinner than the marketing suggests. Here's the honest state of it, plus how the forms actually differ.

Cannabinoids

CBN vs CBD for Sleep: What I Feel vs What the Research Says

The two get blended together constantly. They're not the same molecule and they don't do the same thing at night. Here's where the evidence is — and where it isn't.

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