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.
Fifty-two cards correspond to fifty-two weeks in a year. Hearts correspond to the element of water, and signify love, friendship, happiness, and domestic concerns. Generally speaking, they are âhappyâ cards. Clubs correspond to the element of fire, and generally signify business, ambition, and achievement issues.