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 must contain only Legal cards.  The Main Deck can have a minimum of 40 cards and a maximum of 60 cards. (Only the cards in the Main Deck, not cards in the Extra Deck, count toward this total.)