"Regarding your question concerning the Fast: Travellers are exempt from
fasting, but if they want to fast while they are travelling, they are free
to do so. You are exempt the whole period of your travel, not just the
hours you are in a train or car, etc. If one eats unconsciously during the
fasting hours, this is not breaking the Fast as it is an accident. The age
limit is 70 years, but if one desires to fast after the age limit is
passed, and is strong enough to, one is free to do so. If during the Fast
period a person falls ill and is unable to fast, but recovers before the
Fast period is over, he can start to fast again and continue until the
end. Of course the Fast, as you know, can only be kept during the month
set aside for that purpose."