Plain Facts for Old and Young by John Harvey Kellogg

3. If insufficient sleep is taken at night, sleep a few minutes just

before dinner. Half an hour's rest at this time is remarkably refreshing; and even fifteen minutes spent in sleep will be found very reviving. Do not sleep after dinner, as a pollution will be very likely to occur, and, as a rule, after-dinner naps are unrefreshing and productive of indigestion.