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Afternoon caffeine stays active while you sleep

Caffeine has a multi-hour half-life in the body. An afternoon cup leaves enough active substance at bedtime to degrade your sleep quality, even if you fall asleep easily.

The principle

Half-life keeps caffeine circulating for hours

Caffeine takes roughly five to six hours to reduce by half. A quarter of the caffeine from a four o'clock coffee remains in your system at ten o'clock at night.

The mechanism

Sleep depth degrades without obvious waking

Caffeine blocks adenosine, the brain chemical signaling deep rest. You may fall asleep quickly, but residual caffeine prevents the deep sleep stages needed to feel refreshed.

The silent impact

Metabolic speed varies widely across individuals

Genetic factors cause caffeine clearance rates to differ greatly between people. Moving your final cup to morning for several days tests whether afternoon caffeine impairs your rest.

How to test

Idea

Afternoon Coffee Leaves an Invisible Trail at Bedtime

Caffeine remains active for hours, reducing sleep quality even when you fall asleep easily.

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@spot #caffeine #sleep #health #metabolism

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