The CIPD is urging organisations to agree any flexibility before England's 1am World Cup last-16 tie to help minimise disruption at the start of the working week.
Nearly half of UK workers say they end most working days mentally exhausted as rising workplace pressure leaves employees and managers struggling to switch off.
Earlier this week, an employment tribunal ruled that two maintenance workers, who were sacked for raising concerns about health and safety at troubled Liverpool Prison, had been unfairly dismissed.