Your heartbeat has a "signature" based on your overall personality.
A German study at the Freie Universitat Berlin indicated that personality’s effect on heartbeat may be so pervasive that it could actually be used as a more reliable alternative to personality tests. The mechanism of this effect on the heart is not known, and could be direct or indirect (e.g., the brain influencing the heart directly, or personality having a broader impact on breathing patterns, which would then affect one’s heartbeat). A previous electrocardiograph study indicated to researchers that people with more emotionless personalities were more likely to have certain electrical activity patterns, and this follow-up study determined that specific patterns also exist for people who rate high in neuroticism or who experience fewer positive emotions.
The Vocal Ranges of the Greatest Singers. From Mariah Carey’s ear-piercing whistle to Barry White’s deep bassy growl, compare the vocal ranges of today’s top artists with the greatest of all time. (via ConcertHotels.com).