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.
enlarge image. 9 hearts [plural, uncountable] one of the four sets of cards (called suits ) in a pack / deck of cards, with red heart symbols on them the queen of hearts Hearts is/are trumps. See related entries: Card games.