Relaxation during work day is essential and standard times fixed by industrial engineers have relaxation time built into them. Managers have to allow the employees to relax within the planned relaxation time.
It is important to note that F.W. Taylor improved productivity by even 100% by giving rest of more than 50% to a person loading pigs. That experiment and the theory based on that shows that relaxation during the work day is very important and essential. That is why a tea break is normal part of work day. Similarly toilet break and water break are also normal.