Coffee and Sleep

Caffeine's half-life is 5 to 6 hours in most adults. If you drink 200mg of caffeine at 2 PM, approximately 100mg is still circulating at 8 PM. At midnight, roughly 50mg remains. That 50mg is enough to disrupt sleep architecture even if you fall asleep at your normal time.

What Caffeine Does to Sleep

Research shows that caffeine consumed 6 hours before bedtime reduces total sleep time by an average of 41 minutes and decreases deep sleep (slow-wave sleep), the most restorative phase. You may not feel the deficit — people are notoriously bad at self-assessing sleep quality. The cumulative effect over weeks and months is chronic under-recovery.

The Cutoff

The most commonly recommended caffeine cutoff is 6 to 8 hours before your intended bedtime. If you go to bed at 10 PM: last coffee by 2 to 4 PM. For afternoons when you need something warm, decaf has 5 to 15mg, matcha delivers caffeine with L-theanine that slows absorption, and London Fog has 55mg from Earl Grey. Coffee and sleep are not enemies. They are partners with a scheduling conflict. Find your cutoff. Protect your sleep. Your morning coffee will taste better because you are actually rested enough to appreciate it. Find a specialty shop near you.

Keep reading: How Much Coffee Is Too Much, Best Time to Drink Coffee, Coffee and Anxiety.