☕ Pharmacokinetics & Sleep Hygiene
Caffeine Half-Life & Sleep Cutoff Calculator
Model bloodstream caffeine elimination curves, determine remaining milligrams at bedtime, and establish your personalized afternoon cutoff time to protect deep slow-wave sleep.
☕ Drip Coffee (95mg)
⚡ Double Espresso (150mg)
🥫 Energy Drink (160mg)
🫖 Black Tea (47mg)
🏋️ Pre-Workout (200mg)
Consumption Timeline
Remaining in Bloodstream at Bedtime
43.2 mg
Elapsed Time
9.0 Hours
Eliminated
71.2%
Recommended Cutoff
13:00 (1:00 PM)
💡 Adenosine Receptor Physics:
To keep bedtime caffeine levels below 20mg (preventing stage 3/4 slow-wave deep sleep disruption), stop consuming caffeine at least 10 hours before sleep.
The Pharmacokinetics of Caffeine
Caffeine blocks adenosine receptors ($A_1$ and $A_{2A}$) in the central nervous system, temporarily delaying sleep pressure.
- Exponential Decay Formula: $$C(t) = C_0 \times \left(\frac{1}{2}\right)^{t / t_{1/2}}$$
- Slow-Wave Sleep Impact: Even if you fall asleep easily with residual caffeine in your bloodstream, clinical polysomnography studies show it degrades restorative delta-wave deep sleep and REM architecture.