5 Cycles of CPR takes 2 minutes

Newly trained BLS providers were more likely to spend two minutes counting 5 cycles of 30:2 compression:ventilation than to correctly identify when two minutes had elapsed.

Using the 30 : 2 compression–ventilation ratio: five cycles is easier to follow than 2 min of cardiopulmonary resuscitation
Eur J Emerg Med. 2009 Dec;16(6):339-41