Thanks Crimson, much appreciated. I did a
google to find more info:
"Commonly, sinus bradycardia is an incidental finding in otherwise healthy individuals, particularly in young or sleeping patients. Other causes of sinus bradycardia are related to increased vagal tone.
Physiologic causes of increased vagal tone include the bradycardia seen in athletes. "
Sounds good to me (cos I really don't like the "prognosis" section on some of those pages).