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La caffeina, nota sostanza stimolante, non ha effetti sul sonno di chi è abituato a bere regolarmente caffè. È quanto mostra uno studio austro-svizzero condotto con la guida dell'Università di Basilea. In compenso, sono state registrate modifiche a livello cerebrale.
Il team di ricercatori ha reclutato venti giovani in salute che bevono regolarmente caffè. Sull'arco di dieci giorni i partecipanti hanno ingerito, 10 di loro, pastiglie di caffeina e per altri dieci un placebo.
Misurazioni cerebrali, effettuate nel laboratorio del sonno, hanno mostrato che i partecipanti dormivano allo stesso modo in tutti i casi. Le analisi hanno però evidenziato che, dopo dieci giorni di astinenza dalla caffeina, la materia grigia diventava più grande rispetto ai dieci giorni con la sostanza stimolante. Il fenomeno non è però preoccupante, perché sembra trattarsi di effetti temporanei.
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