Coffee as a sleep aid

You probably noticed more than once that sometimes drinking a cup of good coffee starts sleepy at the time, as it should occur vigor. Why it happens and what is the reason for this lethargy? Scientists have found that drunk a cup of coffee invigorates a man is a consequence of the effect 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 fact is that this drink constricts blood vessels in the brain. Therefore, if you drink too much strong coffee, is not limited to just one cup, certainly comes drowsiness, expected vigor and does not come, but a man dumped "weakness" and lethargy. Especially in the winter and spring seasons of strong coffee may be sleepy, so it is best to drink to drink milk and be limited to one cup. See also: Creativity helps a nap. How to look at the fine after a sleepless night? How to sleep for good health? Why is so nice in the morning to stretch? Why falling asleep, we experience the sensation of falling? Seven ways to stay awake on the job.

Source: otvetin.ru/another/27684-pochemu-inogda-ot-kofe-xochetsya-spat.html