The Babylonians created the concept we now call an “hour”, though they probably didn’t have 21st century business meetings in mind at the time. An hour is a nice, round number but that’s about all it has going for it as a universal time allocation for gatherings. Parkinson’s Law says “work expands to fill the time available for its completion” so if we set aside an hour for every meeting, the meeting will take that time, though we won’t necessarily get more done than if we had allocated it less time. So the advice is to either vary meeting length depending on the agenda (and of course sometimes 60 minutes will be right!) or to universally apply a shorter time, e.g. 30 or 45 minutes. This forces everyone to get the most out of the time you have.
Source: learn.filtered.com