Coffee can interfere with falling asleep if the last cup is drunk less than six hours before bedtime. This warning was given by nutritionist Amanda Figueiredo from the University of São Paulo in an interview with Terra.
Caffeine is a stimulant of the central nervous system — it increases mental and physical performance and reduces feelings of fatigue. However, this substance also blocks the production of melatonin, a sleep hormone, which causes difficulty falling asleep.
According to the expert, the half-life of caffeine in the body is four to six hours — this is how long it takes for the level of the substance in the blood to decrease by half.
Figueiredo noted that the reaction to caffeine largely depends on individual characteristics. Sensitivity to the drink is influenced by genetics, age, daily biorhythms, and medication. Therefore, the “six-hour rule” is not universal for everyone — it is only a rough guideline.
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