Employers are being urged to allow flexible working in the coming weeks so any sports-mad staff can watch the Olympics.
The conciliation service Acas issued guidance to help firms deal with any potential problems after the Games start next month.
Bosses were advised to consider allowing staff to start later or finish early, and then agree when time could be made up.
Workers should also be allowed to swap shifts, said Acas.
Chairman Sir Brendan Barber said: "Rio 2016 will be an exciting event for many sports fans but staff should avoid getting disqualified for unreasonable demands or behaviour in the workplace during this period.
"Many businesses need to maintain a certain staffing level in order to survive and sprint to that finish line.
"Employers should have a set of simple workplace agreements in place before the starting gun goes off for the Olympic Games.
"These agreements can help ensure businesses remain productive whilst keeping staff happy too, which are key ingredients for a gold medal winning team line up.
"Our guidance can help managers get the best from their team athletes by planning for potential hurdles, arranging team relay handovers if necessary and avoiding unnecessary false starts."