PREHAB
The Recovery Library

Consume. Clear.
Create.

Everything we take in asks something of the body, and the body answers by adapting. The dose decides whether it adapts toward strength or toward dependence. The time between doses decides whether it gets to recover. This library collects what the research actually says, one substance at a time.

Consume→Clear→Recover→Create
Educational only. Not medical advice. Nothing here recommends starting, stopping, or dosing any substance. People differ widely, and pregnancy, medications, heart conditions, and anxiety disorders change the picture. Talk to a physician about your own situation. Every claim links to its source.
00 · Start here
Intention, ritual, habit
01 · Open
Caffeine
02 · Members
Nicotine
03 · Members
Cannabis
04 · Members
Alcohol
05 · Members
Protein
06 · Members
Sardines & omega-3
07 · Members
Creatine
08 · Members
Sleep
09 · Members
Fasting
00 · Start here

Intention, ritual, habit

Why we wait for caffeine to clear, and what the rest of what we consume might be asking of us.

In the caffeine entry below, the advice comes down to one idea: let it clear before you take it again. The effect stays sharp, the cost stays small, and you stay the one deciding. That raises a question worth sitting with. If it works for caffeine, why don't we treat everything else we take in the same way?

Everything has a rhythm

Anything that changes your brain chemistry builds tolerance: caffeine, nicotine, alcohol, cannabis. Give the brain a constant signal and it adjusts to cancel it out. That's why the first coffee of a new habit feels like a gift, and the hundredth just brings you back to normal. For that kind of substance, the gap between doses matters as much as the dose.

Food works differently, but it has a rhythm too. It doesn't build tolerance the way a drug does. Still, the hours between meals aren't empty. When you stop eating for a while, insulin falls and the body switches from burning what you just ate to burning what it has stored. Researchers call this metabolic switching, and a long overnight gap is the simplest way to get it.5 In one small trial, men who ate all their food within six hours, finishing by mid-afternoon, had better insulin sensitivity and lower blood pressure after five weeks, even though they didn't lose weight.6 But the evidence is mixed: in a year-long trial, eating in an eight-hour window didn't help people lose more weight than simply eating less.7 The honest summary: your body handles food better with a break, even if the scale doesn't move any faster.

An old relationship

We have been drinking alcohol for a long time, longer than we've been human. About ten million years ago, a gene change in our primate ancestors made them roughly forty times better at breaking down ethanol, probably because they were eating fermented fruit that had fallen to the ground.1 That's a real case of a body adapting to a substance.

Caffeine and nicotine are different. Plants make them to poison the insects that eat them. They work on us because they happen to fit locks we already had for other reasons. Caffeine blocks adenosine, the molecule that tells you you're tired. Nicotine imitates acetylcholine. THC imitates the cannabinoids your brain makes on its own. Some researchers think early humans may even have used plant toxins against parasites,2 though that's still debated. Either way, these substances mostly borrowed our wiring. We didn't grow new wiring for them.

How intention turns into habit

What happens inside one lifetime is better understood. Using a substance usually starts as a choice with a reason: I want to feel awake, I want to relax, I want to belong. Neuroscientists call this goal-directed behavior. With repetition, control shifts to the brain's habit system. The behavior starts running on cues instead of reasons: the morning, the break, the phone in your hand. For some people it goes one step further and becomes compulsive.3

Intention wears down, and the habit pathway grows stronger.

What gets passed down

Habits like these don't travel through DNA. There are a few striking and still-debated animal studies suggesting a parent's experience can leave chemical marks on its offspring,4 but nothing like that has been shown for human substance habits.

What does get passed down is culture. The coffee ceremony. Tea poured at a set hour. Wine blessed on Friday night and then put away. Tobacco smoked in some Native traditions only as prayer. Many rituals had intention built into them: when, how much, and why. Over generations, the ritual often survives while the reason fades, and what's left looks a lot like habit.

Taking the intention back

So the practice here is simple, and it's the same one we use on the floor. Find your edge. With a stretch, the edge is where you feel it pull. With a substance, it's the dose where the effect is real and the cost is small, taken on purpose, with enough time between to clear.

Use it with a reason. Let it clear. Come back to it as a choice, not a reflex. The entries below show what that looks like for each thing, one at a time.

Sources
  1. Carrigan MA, et al. Hominids adapted to metabolize ethanol long before human-directed fermentation. PNAS. 2015;112(2):458–463. doi:10.1073/pnas.1404167111
  2. Sullivan RJ, Hagen EH, Hammerstein P. Revealing the paradox of drug reward in human evolution. Proc R Soc B. 2008;275:1231–1241. doi:10.1098/rspb.2007.1673
  3. Everitt BJ, Robbins TW. Neural systems of reinforcement for drug addiction: from actions to habits to compulsion. Nature Neuroscience. 2005;8:1481–1489. doi:10.1038/nn1579
  4. Dias BG, Ressler KJ. Parental olfactory experience influences behavior and neural structure in subsequent generations. Nature Neuroscience. 2014;17:89–96. doi:10.1038/nn.3594
  5. de Cabo R, Mattson MP. Effects of intermittent fasting on health, aging, and disease. NEJM. 2019;381:2541–2551. doi:10.1056/NEJMra1905136
  6. Sutton EF, et al. Early time-restricted feeding improves insulin sensitivity, blood pressure, and oxidative stress even without weight loss in men with prediabetes. Cell Metabolism. 2018;27:1212–1221. doi:10.1016/j.cmet.2018.04.010
  7. Liu D, et al. Calorie restriction with or without time-restricted eating in weight loss. NEJM. 2022;386:1495–1504. doi:10.1056/NEJMoa2114833
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01 · Consume

Caffeine

The most-studied performance aid there is. Real benefits, real costs, and both depend on how much and how often.

4–6 h
Average half-life in adults (range about 1.5–10 h)1
3–6
mg per kg of body weight: the studied range for performance1
400 mg
Daily intake regulators consider not a safety concern for healthy adults2,3
~1 day
About 5 half-lives, when roughly 97% has cleared (at a 5 h half-life)

How it works

Through the day, a molecule called adenosine builds up in the brain and slowly signals fatigue. Caffeine fits the same receptors and blocks them. You don't make less adenosine; you just stop hearing it for a while. When the caffeine clears, the signal returns, sometimes all at once.

What the research supports

Potential benefits

  • Consistently improves exercise performance at 3–6 mg/kg, most often taken about 60 minutes before training. Doses as low as 2 mg/kg may help.1
  • Improves alertness, reaction time, and focus, especially when tired.1
  • In large observational studies, about 3–4 cups of coffee a day was associated with lower all-cause mortality than none. Association, not proof, and it concerns coffee rather than caffeine alone.4

Costs

  • Disturbs sleep long after it's felt: 400 mg taken 6 hours before bed cut measured sleep by more than an hour.5
  • Very high doses (around 9 mg/kg) bring frequent side effects without extra performance.1
  • Daily use builds tolerance. In one study, the performance boost from 3 mg/kg a day was largest on day 1 and faded after about 15 days.6
  • Stopping after regular use brings withdrawal (headache, fatigue, low mood), typically starting 12–24 hours after the last dose.7

Clear: watch it leave

Set your dose, the time you take it, and your bedtime. Half-life varies a lot between people. Smoking speeds it up. Pregnancy, hormonal contraceptives, and some genes slow it down.1

Caffeine remaining in the body over 30 hours

Model: simple first-order elimination (amount × ½t / half-life). It ignores absorption time and individual variation, so treat it as a picture of the curve, not a measurement.

The spiral: many days at once

One dose rises, peaks, and falls away. But the next morning it rises again. Lay the days end to end and you get waves. Wrap each day around a clock face and every day becomes one lap. Stack the laps and the cycle becomes a coil. It's the same numbers, seen from three planes.

When each lap lands where the last one did, you're in balance. When the laps keep widening, the substance is piling up faster than you clear it: that's a spiral outward. When you space the doses out, the laps close back toward the center, which is what clearing looks like.

Plane I · Time
Plane II · The clock
Plane III · The coil

Model: a dose is absorbed over about an hour (peak near 1 h), then cleared at the half-life you set. Doses add together. On the clock, midnight is at the top, and distance from the center is the amount in the body. Lighter laps are earlier days; darker laps are later.

Create: the moderation principle

What the research above adds up to. These are observations, not instructions.

  1. The effect is strongest when it's occasional. Tolerance builds with daily use and fades with time off.6
  2. Protect the recovery window. Sleep is when adaptation happens, and caffeine still in the system at bedtime takes from it.5
  3. Less can be enough. Benefits appear at doses well below where side effects climb.1
  4. Let it clear. Giving the body time to fully clear a substance before the next dose keeps its effect sharper and dependence smaller.
Sources
  1. Guest NS, et al. International Society of Sports Nutrition position stand: caffeine and exercise performance. J Int Soc Sports Nutr. 2021;18:1. doi:10.1186/s12970-020-00383-4
  2. EFSA Panel on Dietetic Products, Nutrition and Allergies. Scientific opinion on the safety of caffeine. EFSA Journal. 2015;13(5):4102. doi:10.2903/j.efsa.2015.4102
  3. U.S. Food and Drug Administration. Spilling the Beans: How Much Caffeine Is Too Much? fda.gov
  4. Poole R, et al. Coffee consumption and health: umbrella review of meta-analyses of multiple health outcomes. BMJ. 2017;359:j5024. doi:10.1136/bmj.j5024
  5. Drake C, et al. Caffeine effects on sleep taken 0, 3, or 6 hours before going to bed. J Clin Sleep Med. 2013;9(11):1195–1200. doi:10.5664/jcsm.3170
  6. Lara B, et al. Time course of tolerance to the performance benefits of caffeine. PLoS ONE. 2019;14(1):e0210275. doi:10.1371/journal.pone.0210275
  7. Juliano LM, Griffiths RR. A critical review of caffeine withdrawal: empirical validation of symptoms and signs, incidence, severity, and associated features. Psychopharmacology. 2004;176:1–29. doi:10.1007/s00213-004-2000-x
Members

The rest of the library

Eight more entries in the same format as caffeine: what it does, what it costs, how long it takes to clear, and what the research says, every claim sourced. Each has its own tool, from a nicotine clearance curve to a fasting clock. New entries as they're written.

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