https://todaypurpose.com/tags/caffeine/Recent content in Caffeine on Today PurposeHugoenMon, 06 Jul 2026 00:00:00 +0000https://todaypurpose.com/wiki/caffeine-and-sleep/Mon, 06 Jul 2026 00:00:00 +0000https://todaypurpose.com/wiki/caffeine-and-sleep/<p>Two molecules explain most of what caffeine does — and give you a couple of free levers.</p> <h2 id="adenosine--the-sleep-pressure-molecule">Adenosine — the sleep-pressure molecule</h2> <ul> <li><strong>Adenosine builds up</strong> through the day and creates &ldquo;sleep pressure&rdquo;; sleep clears it (Coffee).</li> <li><strong>Caffeine blocks adenosine receptors</strong> (15–20 min after drinking), so you feel less sleepy — but the adenosine is still there, waiting.</li> <li><strong>Delay coffee ~90 minutes after waking</strong> (Andrew Huberman): let your body clear the overnight adenosine first. Drink it immediately and you just park the tiredness for an afternoon crash.</li> </ul> <h2 id="cortisol--the-alertness-hormone">Cortisol — the alertness hormone</h2> <ul> <li>Cortisol naturally <strong>peaks ~2 hours after waking</strong>. Caffeine makes it rise faster and sooner, and you build <strong>tolerance</strong> — which is why people creep up to more cups to get the same alertness (Coffee).</li> <li>Michael Pollan&rsquo;s note: quit for ~3 months and caffeine hits like a drug again.</li> </ul> <h2 id="sleep-itself">Sleep itself</h2> <p>Sleep pressure <em>is</em> adenosine (Head Strong on sleep). Two adjacent levers from the reading:</p>