Why does a 3pm coffee still wreck your sleep?

Half the caffeine in your afternoon coffee is still awake inside you five hours later.

Caffeine has a half-life of about 5 hours - your body clears only half of it in that time. So a coffee at 3pm still leaves a real dose circulating at 8pm, blocking the chemical that makes you feel sleepy.

You drink a 40k coffee at 3pm to push through work. By 8pm half of it is still in you, and even after you fall asleep your deep sleep is cut.

Stop caffeine by early afternoon - falling asleep does not mean the caffeine is gone.

Timing your last coffee earlier is the cheapest way to protect your sleep without giving up coffee.

5-hour half-life: a 3pm cup is still half-on at 8pm.

Learn the idea and practice English at the same time.