32yo, restinghr=60. recently started biking 2 lose 60lbs. had night of bad sleep, upper body aches & panic, and now rhr is 45. scared of heart attack!?

Probably OK: I am so glad that you decided to do something to improve your health. I can't quite make out what you meant by your current resting heart rate, but the other things you describe don't sound medically serious. If you haven't done so, i would suggest you contact your doctor and get a physical exam before resuming your biking. That way you can get advice and reassurance before your start again.

No worry!: When i was a professor in ohio, i was biking 150m per week on average. My pulse rate would drop to 36-38 bpm, while sitting and reading. What happens when you do cardio, your resting rate will drop. This is because of its effect on the sino-atrial node in your heart slowing. Don't worry, your av node kicks in an dwill keep your ticker going. Elite athletes can have resting rates of 30-36!