Why is it sometimes from the coffee you want to sleep?

Why is it sometimes from the coffee you want to sleep?

You probably noticed more than once that sometimes drunk from the cup of strong coffee starts to get sleepy at the time, as it should occur vigor. Why it happens and what is the cause of this lethargy?

Scientists have found that drunk one cup of coffee invigorates a man is a consequence of the action of caffeine. That caffeine gives some excitement, vigor, the person feels a surge of strength and energy.

But if after a cup of drink the second and third - comes drowsiness (especially if the coffee is brewed strong). The thing is that this drink narrows the vessels of the brain. Therefore, if you drink too much strong coffee, is not limited to just one cup, surely there comes drowsiness, the expected vigor and does not come, but a man dumped "weakness" and lethargy. Especially in winter and spring seasons of strong coffee may be sleepy, so the drink is better to drink milk, and limited to one cup.

See also:

  • Creativity helps a nap.
  • How to look at the fine after a sleepless night?
  • How long should I sleep for good health?
  • Why in the morning is so nice to stretch?
  • Why is falling asleep, we experience the sensation of falling?
  • Seven Ways to do not fall asleep at the workplace.