The current norms were established by Pope Paul VI in 1964 and replace the former ruling which required one to fast from midnight.

Out of reverence for what one is to receive, we are asked, the Church says, to refrain from taking food or drink for one hour before receiving Communion (this means the time of receiving Communion itself, not the time when the Mass begins). Note that 'food and drink' does not include water, or any kind of medicine. Note also that the elderly, and those who are ill in any way, as well as those who care for them, are not bound by this one hour of fast.

The Spirit of the law is to give shape to our respect for the Eucharist. But we should use the law in an intelligent and mature fashion. There is no definition of what is, or is not, 'elderly' or 'sick'. And we should not be anxiously scanning our watches ("Is it 59 minutes? ....)