Paul McCartney wrote this as Hey Jules, a song meant to comfort John Lennon's 5-year-old son Julian as his parents were getting a divorce. The change to Jude was inspired by the character Jud in the musical Oklahoma! (McCartney loves show tunes)
The medical term for a slow heart rate is bradycardia; generally defined as a heart rate below 60 bpm (beats per minute). In contrast, tachycardia means fast heart rate above 100 bpm.
Bradycardia, also known as bradyarrhythmia, is a slow heart rate, namely, a resting heart rate of under 60 beats per minute (BPM) in adults. It is a type of cardiac arrhythmia. It seldom results in symptoms until the rate drops below 50 BPM. It sometimes results in fatigue, weakness, dizziness, and at very low rates fainting. During sleep, a slow heartbeat with rates around 40â50 BPM is common, and is considered normal.