Caffeine Clearance Model
Estimate the amount of active caffeine remaining in your system at bedtime.
Standard cup of coffee = 100-150mg. Energy drink = 150-300mg.
Active Caffeine at Bedtime:
Even 50mg (half a cup) active in your system at bedtime can reduce deep NREM sleep by up to 20%, even if you don't feel it and fall asleep easily.
Methodology & Assumptions
Receptor Blockade
Caffeine is an adenosine receptor antagonist. It blocks the brain's sleepiness signal. The average half-life in a healthy adult is 5 to 6 hours. This means a 200mg dose at 4 PM leaves 100mg active at 9 PM, and 50mg active at 2 AM.