Not enough sleep or disruptions to the sleep-wake cycle (such as those that may occur with shift work or travelling to a different time zone) cause the physiological state known as fatigue. Staying awake for 24 hours leads to a reduced hand-to-eye coordination that is similar to having a blood alcohol content of 0.1.
There are 13 hearts in a standard 52 card deck. There are also 13 diamonds, 13 spades and 13 clubs.
1 The Main Deck can have a minimum of 40 cards and a maximum of 60 cards.  A Duelist may not have more than three copies of any Unlimited card included in their Main Deck, Side Deck, and Extra Deck combined.